diff options
Diffstat (limited to 'drivers/block/null_blk/main.c')
| -rw-r--r-- | drivers/block/null_blk/main.c | 2214 |
1 files changed, 2214 insertions, 0 deletions
diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c new file mode 100644 index 000000000000..c7c0fb79a6bf --- /dev/null +++ b/drivers/block/null_blk/main.c @@ -0,0 +1,2214 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Add configfs and memory store: Kyungchan Koh <kkc6196@fb.com> and + * Shaohua Li <shli@fb.com> + */ +#include <linux/module.h> + +#include <linux/moduleparam.h> +#include <linux/sched.h> +#include <linux/fs.h> +#include <linux/init.h> +#include "null_blk.h" + +#undef pr_fmt +#define pr_fmt(fmt) "null_blk: " fmt + +#define FREE_BATCH 16 + +#define TICKS_PER_SEC 50ULL +#define TIMER_INTERVAL (NSEC_PER_SEC / TICKS_PER_SEC) + +#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION +static DECLARE_FAULT_ATTR(null_timeout_attr); +static DECLARE_FAULT_ATTR(null_requeue_attr); +static DECLARE_FAULT_ATTR(null_init_hctx_attr); +#endif + +static inline u64 mb_per_tick(int mbps) +{ + return (1 << 20) / TICKS_PER_SEC * ((u64) mbps); +} + +/* + * Status flags for nullb_device. + * + * CONFIGURED: Device has been configured and turned on. Cannot reconfigure. + * UP: Device is currently on and visible in userspace. + * THROTTLED: Device is being throttled. + * CACHE: Device is using a write-back cache. + */ +enum nullb_device_flags { + NULLB_DEV_FL_CONFIGURED = 0, + NULLB_DEV_FL_UP = 1, + NULLB_DEV_FL_THROTTLED = 2, + NULLB_DEV_FL_CACHE = 3, +}; + +#define MAP_SZ ((PAGE_SIZE >> SECTOR_SHIFT) + 2) +/* + * nullb_page is a page in memory for nullb devices. + * + * @page: The page holding the data. + * @bitmap: The bitmap represents which sector in the page has data. + * Each bit represents one block size. For example, sector 8 + * will use the 7th bit + * The highest 2 bits of bitmap are for special purpose. LOCK means the cache + * page is being flushing to storage. FREE means the cache page is freed and + * should be skipped from flushing to storage. Please see + * null_make_cache_space + */ +struct nullb_page { + struct page *page; + DECLARE_BITMAP(bitmap, MAP_SZ); +}; +#define NULLB_PAGE_LOCK (MAP_SZ - 1) +#define NULLB_PAGE_FREE (MAP_SZ - 2) + +static LIST_HEAD(nullb_list); +static struct mutex lock; +static int null_major; +static DEFINE_IDA(nullb_indexes); +static struct blk_mq_tag_set tag_set; + +enum { + NULL_IRQ_NONE = 0, + NULL_IRQ_SOFTIRQ = 1, + NULL_IRQ_TIMER = 2, +}; + +static bool g_virt_boundary; +module_param_named(virt_boundary, g_virt_boundary, bool, 0444); +MODULE_PARM_DESC(virt_boundary, "Require a virtual boundary for the device. Default: False"); + +static int g_no_sched; +module_param_named(no_sched, g_no_sched, int, 0444); +MODULE_PARM_DESC(no_sched, "No io scheduler"); + +static int g_submit_queues = 1; +module_param_named(submit_queues, g_submit_queues, int, 0444); +MODULE_PARM_DESC(submit_queues, "Number of submission queues"); + +static int g_poll_queues = 1; +module_param_named(poll_queues, g_poll_queues, int, 0444); +MODULE_PARM_DESC(poll_queues, "Number of IOPOLL submission queues"); + +static int g_home_node = NUMA_NO_NODE; +module_param_named(home_node, g_home_node, int, 0444); +MODULE_PARM_DESC(home_node, "Home node for the device"); + +#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION +/* + * For more details about fault injection, please refer to + * Documentation/fault-injection/fault-injection.rst. + */ +static char g_timeout_str[80]; +module_param_string(timeout, g_timeout_str, sizeof(g_timeout_str), 0444); +MODULE_PARM_DESC(timeout, "Fault injection. timeout=<interval>,<probability>,<space>,<times>"); + +static char g_requeue_str[80]; +module_param_string(requeue, g_requeue_str, sizeof(g_requeue_str), 0444); +MODULE_PARM_DESC(requeue, "Fault injection. requeue=<interval>,<probability>,<space>,<times>"); + +static char g_init_hctx_str[80]; +module_param_string(init_hctx, g_init_hctx_str, sizeof(g_init_hctx_str), 0444); +MODULE_PARM_DESC(init_hctx, "Fault injection to fail hctx init. init_hctx=<interval>,<probability>,<space>,<times>"); +#endif + +/* + * Historic queue modes. + * + * These days nothing but NULL_Q_MQ is actually supported, but we keep it the + * enum for error reporting. + */ +enum { + NULL_Q_BIO = 0, + NULL_Q_RQ = 1, + NULL_Q_MQ = 2, +}; + +static int g_queue_mode = NULL_Q_MQ; + +static int null_param_store_val(const char *str, int *val, int min, int max) +{ + int ret, new_val; + + ret = kstrtoint(str, 10, &new_val); + if (ret) + return -EINVAL; + + if (new_val < min || new_val > max) + return -EINVAL; + + *val = new_val; + return 0; +} + +static int null_set_queue_mode(const char *str, const struct kernel_param *kp) +{ + return null_param_store_val(str, &g_queue_mode, NULL_Q_BIO, NULL_Q_MQ); +} + +static const struct kernel_param_ops null_queue_mode_param_ops = { + .set = null_set_queue_mode, + .get = param_get_int, +}; + +device_param_cb(queue_mode, &null_queue_mode_param_ops, &g_queue_mode, 0444); +MODULE_PARM_DESC(queue_mode, "Block interface to use (0=bio,1=rq,2=multiqueue)"); + +static int g_gb = 250; +module_param_named(gb, g_gb, int, 0444); +MODULE_PARM_DESC(gb, "Size in GB"); + +static int g_bs = 512; +module_param_named(bs, g_bs, int, 0444); +MODULE_PARM_DESC(bs, "Block size (in bytes)"); + +static int g_max_sectors; +module_param_named(max_sectors, g_max_sectors, int, 0444); +MODULE_PARM_DESC(max_sectors, "Maximum size of a command (in 512B sectors)"); + +static unsigned int nr_devices = 1; +module_param(nr_devices, uint, 0444); +MODULE_PARM_DESC(nr_devices, "Number of devices to register"); + +static bool g_blocking; +module_param_named(blocking, g_blocking, bool, 0444); +MODULE_PARM_DESC(blocking, "Register as a blocking blk-mq driver device"); + +static bool g_shared_tags; +module_param_named(shared_tags, g_shared_tags, bool, 0444); +MODULE_PARM_DESC(shared_tags, "Share tag set between devices for blk-mq"); + +static bool g_shared_tag_bitmap; +module_param_named(shared_tag_bitmap, g_shared_tag_bitmap, bool, 0444); +MODULE_PARM_DESC(shared_tag_bitmap, "Use shared tag bitmap for all submission queues for blk-mq"); + +static int g_irqmode = NULL_IRQ_SOFTIRQ; + +static int null_set_irqmode(const char *str, const struct kernel_param *kp) +{ + return null_param_store_val(str, &g_irqmode, NULL_IRQ_NONE, + NULL_IRQ_TIMER); +} + +static const struct kernel_param_ops null_irqmode_param_ops = { + .set = null_set_irqmode, + .get = param_get_int, +}; + +device_param_cb(irqmode, &null_irqmode_param_ops, &g_irqmode, 0444); +MODULE_PARM_DESC(irqmode, "IRQ completion handler. 0-none, 1-softirq, 2-timer"); + +static unsigned long g_completion_nsec = 10000; +module_param_named(completion_nsec, g_completion_nsec, ulong, 0444); +MODULE_PARM_DESC(completion_nsec, "Time in ns to complete a request in hardware. Default: 10,000ns"); + +static int g_hw_queue_depth = 64; +module_param_named(hw_queue_depth, g_hw_queue_depth, int, 0444); +MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: 64"); + +static bool g_use_per_node_hctx; +module_param_named(use_per_node_hctx, g_use_per_node_hctx, bool, 0444); +MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. Default: false"); + +static bool g_memory_backed; +module_param_named(memory_backed, g_memory_backed, bool, 0444); +MODULE_PARM_DESC(memory_backed, "Create a memory-backed block device. Default: false"); + +static bool g_discard; +module_param_named(discard, g_discard, bool, 0444); +MODULE_PARM_DESC(discard, "Support discard operations (requires memory-backed null_blk device). Default: false"); + +static unsigned long g_cache_size; +module_param_named(cache_size, g_cache_size, ulong, 0444); +MODULE_PARM_DESC(cache_size, "Cache size in MiB for memory-backed device. Default: 0 (none)"); + +static bool g_fua = true; +module_param_named(fua, g_fua, bool, 0444); +MODULE_PARM_DESC(fua, "Enable/disable FUA support when cache_size is used. Default: true"); + +static unsigned int g_mbps; +module_param_named(mbps, g_mbps, uint, 0444); +MODULE_PARM_DESC(mbps, "Limit maximum bandwidth (in MiB/s). Default: 0 (no limit)"); + +static bool g_zoned; +module_param_named(zoned, g_zoned, bool, S_IRUGO); +MODULE_PARM_DESC(zoned, "Make device as a host-managed zoned block device. Default: false"); + +static unsigned long g_zone_size = 256; +module_param_named(zone_size, g_zone_size, ulong, S_IRUGO); +MODULE_PARM_DESC(zone_size, "Zone size in MB when block device is zoned. Must be power-of-two: Default: 256"); + +static unsigned long g_zone_capacity; +module_param_named(zone_capacity, g_zone_capacity, ulong, 0444); +MODULE_PARM_DESC(zone_capacity, "Zone capacity in MB when block device is zoned. Can be less than or equal to zone size. Default: Zone size"); + +static unsigned int g_zone_nr_conv; +module_param_named(zone_nr_conv, g_zone_nr_conv, uint, 0444); +MODULE_PARM_DESC(zone_nr_conv, "Number of conventional zones when block device is zoned. Default: 0"); + +static unsigned int g_zone_max_open; +module_param_named(zone_max_open, g_zone_max_open, uint, 0444); +MODULE_PARM_DESC(zone_max_open, "Maximum number of open zones when block device is zoned. Default: 0 (no limit)"); + +static unsigned int g_zone_max_active; +module_param_named(zone_max_active, g_zone_max_active, uint, 0444); +MODULE_PARM_DESC(zone_max_active, "Maximum number of active zones when block device is zoned. Default: 0 (no limit)"); + +static int g_zone_append_max_sectors = INT_MAX; +module_param_named(zone_append_max_sectors, g_zone_append_max_sectors, int, 0444); +MODULE_PARM_DESC(zone_append_max_sectors, + "Maximum size of a zone append command (in 512B sectors). Specify 0 for zone append emulation"); + +static bool g_zone_full; +module_param_named(zone_full, g_zone_full, bool, S_IRUGO); +MODULE_PARM_DESC(zone_full, "Initialize the sequential write required zones of a zoned device to be full. Default: false"); + +static bool g_rotational; +module_param_named(rotational, g_rotational, bool, S_IRUGO); +MODULE_PARM_DESC(rotational, "Set the rotational feature for the device. Default: false"); + +static struct nullb_device *null_alloc_dev(void); +static void null_free_dev(struct nullb_device *dev); +static void null_del_dev(struct nullb *nullb); +static int null_add_dev(struct nullb_device *dev); +static struct nullb *null_find_dev_by_name(const char *name); +static void null_free_device_storage(struct nullb_device *dev, bool is_cache); + +static inline struct nullb_device *to_nullb_device(struct config_item *item) +{ + return item ? container_of(to_config_group(item), struct nullb_device, group) : NULL; +} + +static inline ssize_t nullb_device_uint_attr_show(unsigned int val, char *page) +{ + return snprintf(page, PAGE_SIZE, "%u\n", val); +} + +static inline ssize_t nullb_device_ulong_attr_show(unsigned long val, + char *page) +{ + return snprintf(page, PAGE_SIZE, "%lu\n", val); +} + +static inline ssize_t nullb_device_bool_attr_show(bool val, char *page) +{ + return snprintf(page, PAGE_SIZE, "%u\n", val); +} + +static ssize_t nullb_device_uint_attr_store(unsigned int *val, + const char *page, size_t count) +{ + unsigned int tmp; + int result; + + result = kstrtouint(page, 0, &tmp); + if (result < 0) + return result; + + *val = tmp; + return count; +} + +static ssize_t nullb_device_ulong_attr_store(unsigned long *val, + const char *page, size_t count) +{ + int result; + unsigned long tmp; + + result = kstrtoul(page, 0, &tmp); + if (result < 0) + return result; + + *val = tmp; + return count; +} + +static ssize_t nullb_device_bool_attr_store(bool *val, const char *page, + size_t count) +{ + bool tmp; + int result; + + result = kstrtobool(page, &tmp); + if (result < 0) + return result; + + *val = tmp; + return count; +} + +/* The following macro should only be used with TYPE = {uint, ulong, bool}. */ +#define NULLB_DEVICE_ATTR(NAME, TYPE, APPLY) \ +static ssize_t \ +nullb_device_##NAME##_show(struct config_item *item, char *page) \ +{ \ + return nullb_device_##TYPE##_attr_show( \ + to_nullb_device(item)->NAME, page); \ +} \ +static ssize_t \ +nullb_device_##NAME##_store(struct config_item *item, const char *page, \ + size_t count) \ +{ \ + int (*apply_fn)(struct nullb_device *dev, TYPE new_value) = APPLY;\ + struct nullb_device *dev = to_nullb_device(item); \ + TYPE new_value = 0; \ + int ret; \ + \ + ret = nullb_device_##TYPE##_attr_store(&new_value, page, count);\ + if (ret < 0) \ + return ret; \ + if (apply_fn) \ + ret = apply_fn(dev, new_value); \ + else if (test_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags)) \ + ret = -EBUSY; \ + if (ret < 0) \ + return ret; \ + dev->NAME = new_value; \ + return count; \ +} \ +CONFIGFS_ATTR(nullb_device_, NAME); + +static int nullb_update_nr_hw_queues(struct nullb_device *dev, + unsigned int submit_queues, + unsigned int poll_queues) + +{ + struct blk_mq_tag_set *set; + int ret, nr_hw_queues; + + if (!dev->nullb) + return 0; + + /* + * Make sure at least one submit queue exists. + */ + if (!submit_queues) + return -EINVAL; + + /* + * Make sure that null_init_hctx() does not access nullb->queues[] past + * the end of that array. + */ + if (submit_queues > nr_cpu_ids || poll_queues > g_poll_queues) + return -EINVAL; + + /* + * Keep previous and new queue numbers in nullb_device for reference in + * the call back function null_map_queues(). + */ + dev->prev_submit_queues = dev->submit_queues; + dev->prev_poll_queues = dev->poll_queues; + dev->submit_queues = submit_queues; + dev->poll_queues = poll_queues; + + set = dev->nullb->tag_set; + nr_hw_queues = submit_queues + poll_queues; + blk_mq_update_nr_hw_queues(set, nr_hw_queues); + ret = set->nr_hw_queues == nr_hw_queues ? 0 : -ENOMEM; + + if (ret) { + /* on error, revert the queue numbers */ + dev->submit_queues = dev->prev_submit_queues; + dev->poll_queues = dev->prev_poll_queues; + } + + return ret; +} + +static int nullb_apply_submit_queues(struct nullb_device *dev, + unsigned int submit_queues) +{ + int ret; + + mutex_lock(&lock); + ret = nullb_update_nr_hw_queues(dev, submit_queues, dev->poll_queues); + mutex_unlock(&lock); + + return ret; +} + +static int nullb_apply_poll_queues(struct nullb_device *dev, + unsigned int poll_queues) +{ + int ret; + + mutex_lock(&lock); + ret = nullb_update_nr_hw_queues(dev, dev->submit_queues, poll_queues); + mutex_unlock(&lock); + + return ret; +} + +NULLB_DEVICE_ATTR(size, ulong, NULL); +NULLB_DEVICE_ATTR(completion_nsec, ulong, NULL); +NULLB_DEVICE_ATTR(submit_queues, uint, nullb_apply_submit_queues); +NULLB_DEVICE_ATTR(poll_queues, uint, nullb_apply_poll_queues); +NULLB_DEVICE_ATTR(home_node, uint, NULL); +NULLB_DEVICE_ATTR(queue_mode, uint, NULL); +NULLB_DEVICE_ATTR(blocksize, uint, NULL); +NULLB_DEVICE_ATTR(max_sectors, uint, NULL); +NULLB_DEVICE_ATTR(irqmode, uint, NULL); +NULLB_DEVICE_ATTR(hw_queue_depth, uint, NULL); +NULLB_DEVICE_ATTR(index, uint, NULL); +NULLB_DEVICE_ATTR(blocking, bool, NULL); +NULLB_DEVICE_ATTR(use_per_node_hctx, bool, NULL); +NULLB_DEVICE_ATTR(memory_backed, bool, NULL); +NULLB_DEVICE_ATTR(discard, bool, NULL); +NULLB_DEVICE_ATTR(mbps, uint, NULL); +NULLB_DEVICE_ATTR(cache_size, ulong, NULL); +NULLB_DEVICE_ATTR(zoned, bool, NULL); +NULLB_DEVICE_ATTR(zone_size, ulong, NULL); +NULLB_DEVICE_ATTR(zone_capacity, ulong, NULL); +NULLB_DEVICE_ATTR(zone_nr_conv, uint, NULL); +NULLB_DEVICE_ATTR(zone_max_open, uint, NULL); +NULLB_DEVICE_ATTR(zone_max_active, uint, NULL); +NULLB_DEVICE_ATTR(zone_append_max_sectors, uint, NULL); +NULLB_DEVICE_ATTR(zone_full, bool, NULL); +NULLB_DEVICE_ATTR(virt_boundary, bool, NULL); +NULLB_DEVICE_ATTR(no_sched, bool, NULL); +NULLB_DEVICE_ATTR(shared_tags, bool, NULL); +NULLB_DEVICE_ATTR(shared_tag_bitmap, bool, NULL); +NULLB_DEVICE_ATTR(fua, bool, NULL); +NULLB_DEVICE_ATTR(rotational, bool, NULL); +NULLB_DEVICE_ATTR(badblocks_once, bool, NULL); +NULLB_DEVICE_ATTR(badblocks_partial_io, bool, NULL); + +static ssize_t nullb_device_power_show(struct config_item *item, char *page) +{ + return nullb_device_bool_attr_show(to_nullb_device(item)->power, page); +} + +static ssize_t nullb_device_power_store(struct config_item *item, + const char *page, size_t count) +{ + struct nullb_device *dev = to_nullb_device(item); + bool newp = false; + ssize_t ret; + + ret = nullb_device_bool_attr_store(&newp, page, count); + if (ret < 0) + return ret; + + ret = count; + mutex_lock(&lock); + if (!dev->power && newp) { + if (test_and_set_bit(NULLB_DEV_FL_UP, &dev->flags)) + goto out; + + ret = null_add_dev(dev); + if (ret) { + clear_bit(NULLB_DEV_FL_UP, &dev->flags); + goto out; + } + + set_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags); + dev->power = newp; + ret = count; + } else if (dev->power && !newp) { + if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) { + dev->power = newp; + null_del_dev(dev->nullb); + } + clear_bit(NULLB_DEV_FL_CONFIGURED, &dev->flags); + } + +out: + mutex_unlock(&lock); + return ret; +} + +CONFIGFS_ATTR(nullb_device_, power); + +static ssize_t nullb_device_badblocks_show(struct config_item *item, char *page) +{ + struct nullb_device *t_dev = to_nullb_device(item); + + return badblocks_show(&t_dev->badblocks, page, 0); +} + +static ssize_t nullb_device_badblocks_store(struct config_item *item, + const char *page, size_t count) +{ + struct nullb_device *t_dev = to_nullb_device(item); + char *orig, *buf, *tmp; + u64 start, end; + int ret; + + orig = kstrndup(page, count, GFP_KERNEL); + if (!orig) + return -ENOMEM; + + buf = strstrip(orig); + + ret = -EINVAL; + if (buf[0] != '+' && buf[0] != '-') + goto out; + tmp = strchr(&buf[1], '-'); + if (!tmp) + goto out; + *tmp = '\0'; + ret = kstrtoull(buf + 1, 0, &start); + if (ret) + goto out; + ret = kstrtoull(tmp + 1, 0, &end); + if (ret) + goto out; + ret = -EINVAL; + if (start > end) + goto out; + /* enable badblocks */ + cmpxchg(&t_dev->badblocks.shift, -1, 0); + if (buf[0] == '+') { + if (badblocks_set(&t_dev->badblocks, start, + end - start + 1, 1)) + ret = count; + } else if (badblocks_clear(&t_dev->badblocks, start, + end - start + 1)) { + ret = count; + } +out: + kfree(orig); + return ret; +} +CONFIGFS_ATTR(nullb_device_, badblocks); + +static ssize_t nullb_device_zone_readonly_store(struct config_item *item, + const char *page, size_t count) +{ + struct nullb_device *dev = to_nullb_device(item); + + return zone_cond_store(dev, page, count, BLK_ZONE_COND_READONLY); +} +CONFIGFS_ATTR_WO(nullb_device_, zone_readonly); + +static ssize_t nullb_device_zone_offline_store(struct config_item *item, + const char *page, size_t count) +{ + struct nullb_device *dev = to_nullb_device(item); + + return zone_cond_store(dev, page, count, BLK_ZONE_COND_OFFLINE); +} +CONFIGFS_ATTR_WO(nullb_device_, zone_offline); + +static struct configfs_attribute *nullb_device_attrs[] = { + &nullb_device_attr_badblocks, + &nullb_device_attr_badblocks_once, + &nullb_device_attr_badblocks_partial_io, + &nullb_device_attr_blocking, + &nullb_device_attr_blocksize, + &nullb_device_attr_cache_size, + &nullb_device_attr_completion_nsec, + &nullb_device_attr_discard, + &nullb_device_attr_fua, + &nullb_device_attr_home_node, + &nullb_device_attr_hw_queue_depth, + &nullb_device_attr_index, + &nullb_device_attr_irqmode, + &nullb_device_attr_max_sectors, + &nullb_device_attr_mbps, + &nullb_device_attr_memory_backed, + &nullb_device_attr_no_sched, + &nullb_device_attr_poll_queues, + &nullb_device_attr_power, + &nullb_device_attr_queue_mode, + &nullb_device_attr_rotational, + &nullb_device_attr_shared_tag_bitmap, + &nullb_device_attr_shared_tags, + &nullb_device_attr_size, + &nullb_device_attr_submit_queues, + &nullb_device_attr_use_per_node_hctx, + &nullb_device_attr_virt_boundary, + &nullb_device_attr_zone_append_max_sectors, + &nullb_device_attr_zone_capacity, + &nullb_device_attr_zone_full, + &nullb_device_attr_zone_max_active, + &nullb_device_attr_zone_max_open, + &nullb_device_attr_zone_nr_conv, + &nullb_device_attr_zone_offline, + &nullb_device_attr_zone_readonly, + &nullb_device_attr_zone_size, + &nullb_device_attr_zoned, + NULL, +}; + +static void nullb_device_release(struct config_item *item) +{ + struct nullb_device *dev = to_nullb_device(item); + + null_free_device_storage(dev, false); + null_free_dev(dev); +} + +static struct configfs_item_operations nullb_device_ops = { + .release = nullb_device_release, +}; + +static const struct config_item_type nullb_device_type = { + .ct_item_ops = &nullb_device_ops, + .ct_attrs = nullb_device_attrs, + .ct_owner = THIS_MODULE, +}; + +#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION + +static void nullb_add_fault_config(struct nullb_device *dev) +{ + fault_config_init(&dev->timeout_config, "timeout_inject"); + fault_config_init(&dev->requeue_config, "requeue_inject"); + fault_config_init(&dev->init_hctx_fault_config, "init_hctx_fault_inject"); + + configfs_add_default_group(&dev->timeout_config.group, &dev->group); + configfs_add_default_group(&dev->requeue_config.group, &dev->group); + configfs_add_default_group(&dev->init_hctx_fault_config.group, &dev->group); +} + +#else + +static void nullb_add_fault_config(struct nullb_device *dev) +{ +} + +#endif + +static struct +config_group *nullb_group_make_group(struct config_group *group, const char *name) +{ + struct nullb_device *dev; + + if (null_find_dev_by_name(name)) + return ERR_PTR(-EEXIST); + + dev = null_alloc_dev(); + if (!dev) + return ERR_PTR(-ENOMEM); + + config_group_init_type_name(&dev->group, name, &nullb_device_type); + nullb_add_fault_config(dev); + + return &dev->group; +} + +static void +nullb_group_drop_item(struct config_group *group, struct config_item *item) +{ + struct nullb_device *dev = to_nullb_device(item); + + if (test_and_clear_bit(NULLB_DEV_FL_UP, &dev->flags)) { + mutex_lock(&lock); + dev->power = false; + null_del_dev(dev->nullb); + mutex_unlock(&lock); + } + + config_item_put(item); +} + +static ssize_t memb_group_features_show(struct config_item *item, char *page) +{ + + struct configfs_attribute **entry; + char delimiter = ','; + size_t left = PAGE_SIZE; + size_t written = 0; + int ret; + + for (entry = &nullb_device_attrs[0]; *entry && left > 0; entry++) { + if (!*(entry + 1)) + delimiter = '\n'; + ret = snprintf(page + written, left, "%s%c", (*entry)->ca_name, + delimiter); + if (ret >= left) { + WARN_ONCE(1, "Too many null_blk features to print\n"); + memzero_explicit(page, PAGE_SIZE); + return -ENOBUFS; + } + left -= ret; + written += ret; + } + + return written; +} + +CONFIGFS_ATTR_RO(memb_group_, features); + +static struct configfs_attribute *nullb_group_attrs[] = { + &memb_group_attr_features, + NULL, +}; + +static struct configfs_group_operations nullb_group_ops = { + .make_group = nullb_group_make_group, + .drop_item = nullb_group_drop_item, +}; + +static const struct config_item_type nullb_group_type = { + .ct_group_ops = &nullb_group_ops, + .ct_attrs = nullb_group_attrs, + .ct_owner = THIS_MODULE, +}; + +static struct configfs_subsystem nullb_subsys = { + .su_group = { + .cg_item = { + .ci_namebuf = "nullb", + .ci_type = &nullb_group_type, + }, + }, +}; + +static inline int null_cache_active(struct nullb *nullb) +{ + return test_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags); +} + +static struct nullb_device *null_alloc_dev(void) +{ + struct nullb_device *dev; + + dev = kzalloc(sizeof(*dev), GFP_KERNEL); + if (!dev) + return NULL; + +#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION + dev->timeout_config.attr = null_timeout_attr; + dev->requeue_config.attr = null_requeue_attr; + dev->init_hctx_fault_config.attr = null_init_hctx_attr; +#endif + + INIT_RADIX_TREE(&dev->data, GFP_ATOMIC); + INIT_RADIX_TREE(&dev->cache, GFP_ATOMIC); + if (badblocks_init(&dev->badblocks, 0)) { + kfree(dev); + return NULL; + } + + dev->size = g_gb * 1024; + dev->completion_nsec = g_completion_nsec; + dev->submit_queues = g_submit_queues; + dev->prev_submit_queues = g_submit_queues; + dev->poll_queues = g_poll_queues; + dev->prev_poll_queues = g_poll_queues; + dev->home_node = g_home_node; + dev->queue_mode = g_queue_mode; + dev->blocksize = g_bs; + dev->max_sectors = g_max_sectors; + dev->irqmode = g_irqmode; + dev->hw_queue_depth = g_hw_queue_depth; + dev->blocking = g_blocking; + dev->memory_backed = g_memory_backed; + dev->discard = g_discard; + dev->cache_size = g_cache_size; + dev->mbps = g_mbps; + dev->use_per_node_hctx = g_use_per_node_hctx; + dev->zoned = g_zoned; + dev->zone_size = g_zone_size; + dev->zone_capacity = g_zone_capacity; + dev->zone_nr_conv = g_zone_nr_conv; + dev->zone_max_open = g_zone_max_open; + dev->zone_max_active = g_zone_max_active; + dev->zone_append_max_sectors = g_zone_append_max_sectors; + dev->zone_full = g_zone_full; + dev->virt_boundary = g_virt_boundary; + dev->no_sched = g_no_sched; + dev->shared_tags = g_shared_tags; + dev->shared_tag_bitmap = g_shared_tag_bitmap; + dev->fua = g_fua; + dev->rotational = g_rotational; + + return dev; +} + +static void null_free_dev(struct nullb_device *dev) +{ + if (!dev) + return; + + null_free_zoned_dev(dev); + badblocks_exit(&dev->badblocks); + kfree(dev); +} + +static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer) +{ + struct nullb_cmd *cmd = container_of(timer, struct nullb_cmd, timer); + + blk_mq_end_request(blk_mq_rq_from_pdu(cmd), cmd->error); + return HRTIMER_NORESTART; +} + +static void null_cmd_end_timer(struct nullb_cmd *cmd) +{ + ktime_t kt = cmd->nq->dev->completion_nsec; + + hrtimer_start(&cmd->timer, kt, HRTIMER_MODE_REL); +} + +static void null_complete_rq(struct request *rq) +{ + struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq); + + blk_mq_end_request(rq, cmd->error); +} + +static struct nullb_page *null_alloc_page(void) +{ + struct nullb_page *t_page; + + t_page = kmalloc(sizeof(struct nullb_page), GFP_NOIO); + if (!t_page) + return NULL; + + t_page->page = alloc_pages(GFP_NOIO, 0); + if (!t_page->page) { + kfree(t_page); + return NULL; + } + + memset(t_page->bitmap, 0, sizeof(t_page->bitmap)); + return t_page; +} + +static void null_free_page(struct nullb_page *t_page) +{ + __set_bit(NULLB_PAGE_FREE, t_page->bitmap); + if (test_bit(NULLB_PAGE_LOCK, t_page->bitmap)) + return; + __free_page(t_page->page); + kfree(t_page); +} + +static bool null_page_empty(struct nullb_page *page) +{ + int size = MAP_SZ - 2; + + return find_first_bit(page->bitmap, size) == size; +} + +static void null_free_sector(struct nullb *nullb, sector_t sector, + bool is_cache) +{ + unsigned int sector_bit; + u64 idx; + struct nullb_page *t_page, *ret; + struct radix_tree_root *root; + + root = is_cache ? &nullb->dev->cache : &nullb->dev->data; + idx = sector >> PAGE_SECTORS_SHIFT; + sector_bit = (sector & SECTOR_MASK); + + t_page = radix_tree_lookup(root, idx); + if (t_page) { + __clear_bit(sector_bit, t_page->bitmap); + + if (null_page_empty(t_page)) { + ret = radix_tree_delete_item(root, idx, t_page); + WARN_ON(ret != t_page); + null_free_page(ret); + if (is_cache) + nullb->dev->curr_cache -= PAGE_SIZE; + } + } +} + +static struct nullb_page *null_radix_tree_insert(struct nullb *nullb, u64 idx, + struct nullb_page *t_page, bool is_cache) +{ + struct radix_tree_root *root; + + root = is_cache ? &nullb->dev->cache : &nullb->dev->data; + + if (radix_tree_insert(root, idx, t_page)) { + null_free_page(t_page); + t_page = radix_tree_lookup(root, idx); + WARN_ON(!t_page || t_page->page->private != idx); + } else if (is_cache) + nullb->dev->curr_cache += PAGE_SIZE; + + return t_page; +} + +static void null_free_device_storage(struct nullb_device *dev, bool is_cache) +{ + unsigned long pos = 0; + int nr_pages; + struct nullb_page *ret, *t_pages[FREE_BATCH]; + struct radix_tree_root *root; + + root = is_cache ? &dev->cache : &dev->data; + + do { + int i; + + nr_pages = radix_tree_gang_lookup(root, + (void **)t_pages, pos, FREE_BATCH); + + for (i = 0; i < nr_pages; i++) { + pos = t_pages[i]->page->private; + ret = radix_tree_delete_item(root, pos, t_pages[i]); + WARN_ON(ret != t_pages[i]); + null_free_page(ret); + } + + pos++; + } while (nr_pages == FREE_BATCH); + + if (is_cache) + dev->curr_cache = 0; +} + +static struct nullb_page *__null_lookup_page(struct nullb *nullb, + sector_t sector, bool for_write, bool is_cache) +{ + unsigned int sector_bit; + u64 idx; + struct nullb_page *t_page; + struct radix_tree_root *root; + + idx = sector >> PAGE_SECTORS_SHIFT; + sector_bit = (sector & SECTOR_MASK); + + root = is_cache ? &nullb->dev->cache : &nullb->dev->data; + t_page = radix_tree_lookup(root, idx); + WARN_ON(t_page && t_page->page->private != idx); + + if (t_page && (for_write || test_bit(sector_bit, t_page->bitmap))) + return t_page; + + return NULL; +} + +static struct nullb_page *null_lookup_page(struct nullb *nullb, + sector_t sector, bool for_write, bool ignore_cache) +{ + struct nullb_page *page = NULL; + + if (!ignore_cache) + page = __null_lookup_page(nullb, sector, for_write, true); + if (page) + return page; + return __null_lookup_page(nullb, sector, for_write, false); +} + +static struct nullb_page *null_insert_page(struct nullb *nullb, + sector_t sector, bool ignore_cache) + __releases(&nullb->lock) + __acquires(&nullb->lock) +{ + u64 idx; + struct nullb_page *t_page; + + t_page = null_lookup_page(nullb, sector, true, ignore_cache); + if (t_page) + return t_page; + + spin_unlock_irq(&nullb->lock); + + t_page = null_alloc_page(); + if (!t_page) + goto out_lock; + + if (radix_tree_preload(GFP_NOIO)) + goto out_freepage; + + spin_lock_irq(&nullb->lock); + idx = sector >> PAGE_SECTORS_SHIFT; + t_page->page->private = idx; + t_page = null_radix_tree_insert(nullb, idx, t_page, !ignore_cache); + radix_tree_preload_end(); + + return t_page; +out_freepage: + null_free_page(t_page); +out_lock: + spin_lock_irq(&nullb->lock); + return null_lookup_page(nullb, sector, true, ignore_cache); +} + +static int null_flush_cache_page(struct nullb *nullb, struct nullb_page *c_page) +{ + int i; + unsigned int offset; + u64 idx; + struct nullb_page *t_page, *ret; + void *dst, *src; + + idx = c_page->page->private; + + t_page = null_insert_page(nullb, idx << PAGE_SECTORS_SHIFT, true); + + __clear_bit(NULLB_PAGE_LOCK, c_page->bitmap); + if (test_bit(NULLB_PAGE_FREE, c_page->bitmap)) { + null_free_page(c_page); + if (t_page && null_page_empty(t_page)) { + ret = radix_tree_delete_item(&nullb->dev->data, + idx, t_page); + null_free_page(t_page); + } + return 0; + } + + if (!t_page) + return -ENOMEM; + + src = kmap_local_page(c_page->page); + dst = kmap_local_page(t_page->page); + + for (i = 0; i < PAGE_SECTORS; + i += (nullb->dev->blocksize >> SECTOR_SHIFT)) { + if (test_bit(i, c_page->bitmap)) { + offset = (i << SECTOR_SHIFT); + memcpy(dst + offset, src + offset, + nullb->dev->blocksize); + __set_bit(i, t_page->bitmap); + } + } + + kunmap_local(dst); + kunmap_local(src); + + ret = radix_tree_delete_item(&nullb->dev->cache, idx, c_page); + null_free_page(ret); + nullb->dev->curr_cache -= PAGE_SIZE; + + return 0; +} + +static int null_make_cache_space(struct nullb *nullb, unsigned long n) +{ + int i, err, nr_pages; + struct nullb_page *c_pages[FREE_BATCH]; + unsigned long flushed = 0, one_round; + +again: + if ((nullb->dev->cache_size * 1024 * 1024) > + nullb->dev->curr_cache + n || nullb->dev->curr_cache == 0) + return 0; + + nr_pages = radix_tree_gang_lookup(&nullb->dev->cache, + (void **)c_pages, nullb->cache_flush_pos, FREE_BATCH); + /* + * nullb_flush_cache_page could unlock before using the c_pages. To + * avoid race, we don't allow page free + */ + for (i = 0; i < nr_pages; i++) { + nullb->cache_flush_pos = c_pages[i]->page->private; + /* + * We found the page which is being flushed to disk by other + * threads + */ + if (test_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap)) + c_pages[i] = NULL; + else + __set_bit(NULLB_PAGE_LOCK, c_pages[i]->bitmap); + } + + one_round = 0; + for (i = 0; i < nr_pages; i++) { + if (c_pages[i] == NULL) + continue; + err = null_flush_cache_page(nullb, c_pages[i]); + if (err) + return err; + one_round++; + } + flushed += one_round << PAGE_SHIFT; + + if (n > flushed) { + if (nr_pages == 0) + nullb->cache_flush_pos = 0; + if (one_round == 0) { + /* give other threads a chance */ + spin_unlock_irq(&nullb->lock); + spin_lock_irq(&nullb->lock); + } + goto again; + } + return 0; +} + +static blk_status_t copy_to_nullb(struct nullb *nullb, void *source, + loff_t pos, size_t n, bool is_fua) +{ + size_t temp, count = 0; + struct nullb_page *t_page; + sector_t sector; + + while (count < n) { + temp = min3(nullb->dev->blocksize, n - count, + PAGE_SIZE - offset_in_page(pos)); + sector = pos >> SECTOR_SHIFT; + + if (null_cache_active(nullb) && !is_fua) + null_make_cache_space(nullb, PAGE_SIZE); + + t_page = null_insert_page(nullb, sector, + !null_cache_active(nullb) || is_fua); + if (!t_page) + return BLK_STS_NOSPC; + + memcpy_to_page(t_page->page, offset_in_page(pos), + source + count, temp); + + __set_bit(sector & SECTOR_MASK, t_page->bitmap); + + if (is_fua) + null_free_sector(nullb, sector, true); + + count += temp; + pos += temp; + } + return BLK_STS_OK; +} + +static void copy_from_nullb(struct nullb *nullb, void *dest, loff_t pos, + size_t n) +{ + size_t temp, count = 0; + struct nullb_page *t_page; + sector_t sector; + + while (count < n) { + temp = min3(nullb->dev->blocksize, n - count, + PAGE_SIZE - offset_in_page(pos)); + sector = pos >> SECTOR_SHIFT; + + t_page = null_lookup_page(nullb, sector, false, + !null_cache_active(nullb)); + if (t_page) + memcpy_from_page(dest + count, t_page->page, + offset_in_page(pos), temp); + else + memset(dest + count, 0, temp); + + count += temp; + pos += temp; + } +} + +blk_status_t null_handle_discard(struct nullb_device *dev, + sector_t sector, sector_t nr_sectors) +{ + struct nullb *nullb = dev->nullb; + size_t n = nr_sectors << SECTOR_SHIFT; + size_t temp; + + spin_lock_irq(&nullb->lock); + while (n > 0) { + temp = min_t(size_t, n, dev->blocksize); + null_free_sector(nullb, sector, false); + if (null_cache_active(nullb)) + null_free_sector(nullb, sector, true); + sector += temp >> SECTOR_SHIFT; + n -= temp; + } + spin_unlock_irq(&nullb->lock); + + return BLK_STS_OK; +} + +static blk_status_t null_handle_flush(struct nullb *nullb) +{ + int err; + + if (!null_cache_active(nullb)) + return 0; + + spin_lock_irq(&nullb->lock); + while (true) { + err = null_make_cache_space(nullb, + nullb->dev->cache_size * 1024 * 1024); + if (err || nullb->dev->curr_cache == 0) + break; + } + + WARN_ON(!radix_tree_empty(&nullb->dev->cache)); + spin_unlock_irq(&nullb->lock); + return errno_to_blk_status(err); +} + +static blk_status_t null_transfer(struct nullb *nullb, struct page *page, + unsigned int len, unsigned int off, bool is_write, loff_t pos, + bool is_fua) +{ + struct nullb_device *dev = nullb->dev; + blk_status_t err = BLK_STS_OK; + unsigned int valid_len = len; + void *p; + + p = kmap_local_page(page) + off; + if (!is_write) { + if (dev->zoned) { + valid_len = null_zone_valid_read_len(nullb, + pos >> SECTOR_SHIFT, len); + if (valid_len && valid_len != len) + valid_len -= pos & (SECTOR_SIZE - 1); + } + + if (valid_len) { + copy_from_nullb(nullb, p, pos, valid_len); + off += valid_len; + len -= valid_len; + } + + if (len) + memset(p + valid_len, 0xff, len); + flush_dcache_page(page); + } else { + flush_dcache_page(page); + err = copy_to_nullb(nullb, p, pos, len, is_fua); + } + + kunmap_local(p); + return err; +} + +/* + * Transfer data for the given request. The transfer size is capped with the + * nr_sectors argument. + */ +static blk_status_t null_handle_data_transfer(struct nullb_cmd *cmd, + sector_t nr_sectors) +{ + struct request *rq = blk_mq_rq_from_pdu(cmd); + struct nullb *nullb = cmd->nq->dev->nullb; + blk_status_t err = BLK_STS_OK; + unsigned int len; + loff_t pos = blk_rq_pos(rq) << SECTOR_SHIFT; + unsigned int max_bytes = nr_sectors << SECTOR_SHIFT; + unsigned int transferred_bytes = 0; + struct req_iterator iter; + struct bio_vec bvec; + + spin_lock_irq(&nullb->lock); + rq_for_each_segment(bvec, rq, iter) { + len = bvec.bv_len; + if (transferred_bytes + len > max_bytes) + len = max_bytes - transferred_bytes; + err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset, + op_is_write(req_op(rq)), pos, + rq->cmd_flags & REQ_FUA); + if (err) + break; + pos += len; + transferred_bytes += len; + if (transferred_bytes >= max_bytes) + break; + } + spin_unlock_irq(&nullb->lock); + + return err; +} + +static inline blk_status_t null_handle_throttled(struct nullb_cmd *cmd) +{ + struct nullb_device *dev = cmd->nq->dev; + struct nullb *nullb = dev->nullb; + blk_status_t sts = BLK_STS_OK; + struct request *rq = blk_mq_rq_from_pdu(cmd); + + if (!hrtimer_active(&nullb->bw_timer)) + hrtimer_restart(&nullb->bw_timer); + + if (atomic_long_sub_return(blk_rq_bytes(rq), &nullb->cur_bytes) < 0) { + blk_mq_stop_hw_queues(nullb->q); + /* race with timer */ + if (atomic_long_read(&nullb->cur_bytes) > 0) + blk_mq_start_stopped_hw_queues(nullb->q, true); + /* requeue request */ + sts = BLK_STS_DEV_RESOURCE; + } + return sts; +} + +/* + * Check if the command should fail for the badblocks. If so, return + * BLK_STS_IOERR and return number of partial I/O sectors to be written or read, + * which may be less than the requested number of sectors. + * + * @cmd: The command to handle. + * @sector: The start sector for I/O. + * @nr_sectors: Specifies number of sectors to write or read, and returns the + * number of sectors to be written or read. + */ +blk_status_t null_handle_badblocks(struct nullb_cmd *cmd, sector_t sector, + unsigned int *nr_sectors) +{ + struct badblocks *bb = &cmd->nq->dev->badblocks; + struct nullb_device *dev = cmd->nq->dev; + unsigned int block_sectors = dev->blocksize >> SECTOR_SHIFT; + sector_t first_bad, bad_sectors; + unsigned int partial_io_sectors = 0; + + if (!badblocks_check(bb, sector, *nr_sectors, &first_bad, &bad_sectors)) + return BLK_STS_OK; + + if (cmd->nq->dev->badblocks_once) + badblocks_clear(bb, first_bad, bad_sectors); + + if (cmd->nq->dev->badblocks_partial_io) { + if (!IS_ALIGNED(first_bad, block_sectors)) + first_bad = ALIGN_DOWN(first_bad, block_sectors); + if (sector < first_bad) + partial_io_sectors = first_bad - sector; + } + *nr_sectors = partial_io_sectors; + + return BLK_STS_IOERR; +} + +blk_status_t null_handle_memory_backed(struct nullb_cmd *cmd, enum req_op op, + sector_t sector, sector_t nr_sectors) +{ + struct nullb_device *dev = cmd->nq->dev; + + if (op == REQ_OP_DISCARD) + return null_handle_discard(dev, sector, nr_sectors); + + return null_handle_data_transfer(cmd, nr_sectors); +} + +static void nullb_zero_read_cmd_buffer(struct nullb_cmd *cmd) +{ + struct request *rq = blk_mq_rq_from_pdu(cmd); + struct nullb_device *dev = cmd->nq->dev; + struct bio *bio; + + if (!dev->memory_backed && req_op(rq) == REQ_OP_READ) { + __rq_for_each_bio(bio, rq) + zero_fill_bio(bio); + } +} + +static inline void nullb_complete_cmd(struct nullb_cmd *cmd) +{ + struct request *rq = blk_mq_rq_from_pdu(cmd); + + /* + * Since root privileges are required to configure the null_blk + * driver, it is fine that this driver does not initialize the + * data buffers of read commands. Zero-initialize these buffers + * anyway if KMSAN is enabled to prevent that KMSAN complains + * about null_blk not initializing read data buffers. + */ + if (IS_ENABLED(CONFIG_KMSAN)) + nullb_zero_read_cmd_buffer(cmd); + + /* Complete IO by inline, softirq or timer */ + switch (cmd->nq->dev->irqmode) { + case NULL_IRQ_SOFTIRQ: + blk_mq_complete_request(rq); + break; + case NULL_IRQ_NONE: + blk_mq_end_request(rq, cmd->error); + break; + case NULL_IRQ_TIMER: + null_cmd_end_timer(cmd); + break; + } +} + +blk_status_t null_process_cmd(struct nullb_cmd *cmd, enum req_op op, + sector_t sector, unsigned int nr_sectors) +{ + struct nullb_device *dev = cmd->nq->dev; + blk_status_t badblocks_ret = BLK_STS_OK; + blk_status_t ret; + + if (dev->badblocks.shift != -1) + badblocks_ret = null_handle_badblocks(cmd, sector, &nr_sectors); + + if (dev->memory_backed && nr_sectors) { + ret = null_handle_memory_backed(cmd, op, sector, nr_sectors); + if (ret != BLK_STS_OK) + return ret; + } + + return badblocks_ret; +} + +static void null_handle_cmd(struct nullb_cmd *cmd, sector_t sector, + sector_t nr_sectors, enum req_op op) +{ + struct nullb_device *dev = cmd->nq->dev; + struct nullb *nullb = dev->nullb; + blk_status_t sts; + + if (op == REQ_OP_FLUSH) { + cmd->error = null_handle_flush(nullb); + goto out; + } + + if (dev->zoned) + sts = null_process_zoned_cmd(cmd, op, sector, nr_sectors); + else + sts = null_process_cmd(cmd, op, sector, nr_sectors); + + /* Do not overwrite errors (e.g. timeout errors) */ + if (cmd->error == BLK_STS_OK) + cmd->error = sts; + +out: + nullb_complete_cmd(cmd); +} + +static enum hrtimer_restart nullb_bwtimer_fn(struct hrtimer *timer) +{ + struct nullb *nullb = container_of(timer, struct nullb, bw_timer); + ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL); + unsigned int mbps = nullb->dev->mbps; + + if (atomic_long_read(&nullb->cur_bytes) == mb_per_tick(mbps)) + return HRTIMER_NORESTART; + + atomic_long_set(&nullb->cur_bytes, mb_per_tick(mbps)); + blk_mq_start_stopped_hw_queues(nullb->q, true); + + hrtimer_forward_now(&nullb->bw_timer, timer_interval); + + return HRTIMER_RESTART; +} + +static void nullb_setup_bwtimer(struct nullb *nullb) +{ + ktime_t timer_interval = ktime_set(0, TIMER_INTERVAL); + + hrtimer_setup(&nullb->bw_timer, nullb_bwtimer_fn, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + atomic_long_set(&nullb->cur_bytes, mb_per_tick(nullb->dev->mbps)); + hrtimer_start(&nullb->bw_timer, timer_interval, HRTIMER_MODE_REL); +} + +#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION + +static bool should_timeout_request(struct request *rq) +{ + struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq); + struct nullb_device *dev = cmd->nq->dev; + + return should_fail(&dev->timeout_config.attr, 1); +} + +static bool should_requeue_request(struct request *rq) +{ + struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq); + struct nullb_device *dev = cmd->nq->dev; + + return should_fail(&dev->requeue_config.attr, 1); +} + +static bool should_init_hctx_fail(struct nullb_device *dev) +{ + return should_fail(&dev->init_hctx_fault_config.attr, 1); +} + +#else + +static bool should_timeout_request(struct request *rq) +{ + return false; +} + +static bool should_requeue_request(struct request *rq) +{ + return false; +} + +static bool should_init_hctx_fail(struct nullb_device *dev) +{ + return false; +} + +#endif + +static void null_map_queues(struct blk_mq_tag_set *set) +{ + struct nullb *nullb = set->driver_data; + int i, qoff; + unsigned int submit_queues = g_submit_queues; + unsigned int poll_queues = g_poll_queues; + + if (nullb) { + struct nullb_device *dev = nullb->dev; + + /* + * Refer nr_hw_queues of the tag set to check if the expected + * number of hardware queues are prepared. If block layer failed + * to prepare them, use previous numbers of submit queues and + * poll queues to map queues. + */ + if (set->nr_hw_queues == + dev->submit_queues + dev->poll_queues) { + submit_queues = dev->submit_queues; + poll_queues = dev->poll_queues; + } else if (set->nr_hw_queues == + dev->prev_submit_queues + dev->prev_poll_queues) { + submit_queues = dev->prev_submit_queues; + poll_queues = dev->prev_poll_queues; + } else { + pr_warn("tag set has unexpected nr_hw_queues: %d\n", + set->nr_hw_queues); + WARN_ON_ONCE(true); + submit_queues = 1; + poll_queues = 0; + } + } + + for (i = 0, qoff = 0; i < set->nr_maps; i++) { + struct blk_mq_queue_map *map = &set->map[i]; + + switch (i) { + case HCTX_TYPE_DEFAULT: + map->nr_queues = submit_queues; + break; + case HCTX_TYPE_READ: + map->nr_queues = 0; + continue; + case HCTX_TYPE_POLL: + map->nr_queues = poll_queues; + break; + } + map->queue_offset = qoff; + qoff += map->nr_queues; + blk_mq_map_queues(map); + } +} + +static int null_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob) +{ + struct nullb_queue *nq = hctx->driver_data; + LIST_HEAD(list); + int nr = 0; + struct request *rq; + + spin_lock(&nq->poll_lock); + list_splice_init(&nq->poll_list, &list); + list_for_each_entry(rq, &list, queuelist) + blk_mq_set_request_complete(rq); + spin_unlock(&nq->poll_lock); + + while (!list_empty(&list)) { + struct nullb_cmd *cmd; + struct request *req; + + req = list_first_entry(&list, struct request, queuelist); + list_del_init(&req->queuelist); + cmd = blk_mq_rq_to_pdu(req); + cmd->error = null_process_cmd(cmd, req_op(req), blk_rq_pos(req), + blk_rq_sectors(req)); + if (!blk_mq_add_to_batch(req, iob, cmd->error != BLK_STS_OK, + blk_mq_end_request_batch)) + blk_mq_end_request(req, cmd->error); + nr++; + } + + return nr; +} + +static enum blk_eh_timer_return null_timeout_rq(struct request *rq) +{ + struct blk_mq_hw_ctx *hctx = rq->mq_hctx; + struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq); + + if (hctx->type == HCTX_TYPE_POLL) { + struct nullb_queue *nq = hctx->driver_data; + + spin_lock(&nq->poll_lock); + /* The request may have completed meanwhile. */ + if (blk_mq_request_completed(rq)) { + spin_unlock(&nq->poll_lock); + return BLK_EH_DONE; + } + list_del_init(&rq->queuelist); + spin_unlock(&nq->poll_lock); + } + + pr_info("rq %p timed out\n", rq); + + /* + * If the device is marked as blocking (i.e. memory backed or zoned + * device), the submission path may be blocked waiting for resources + * and cause real timeouts. For these real timeouts, the submission + * path will complete the request using blk_mq_complete_request(). + * Only fake timeouts need to execute blk_mq_complete_request() here. + */ + cmd->error = BLK_STS_TIMEOUT; + if (cmd->fake_timeout || hctx->type == HCTX_TYPE_POLL) + blk_mq_complete_request(rq); + return BLK_EH_DONE; +} + +static blk_status_t null_queue_rq(struct blk_mq_hw_ctx *hctx, + const struct blk_mq_queue_data *bd) +{ + struct request *rq = bd->rq; + struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq); + struct nullb_queue *nq = hctx->driver_data; + sector_t nr_sectors = blk_rq_sectors(rq); + sector_t sector = blk_rq_pos(rq); + const bool is_poll = hctx->type == HCTX_TYPE_POLL; + + might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING); + + if (!is_poll && nq->dev->irqmode == NULL_IRQ_TIMER) { + hrtimer_setup(&cmd->timer, null_cmd_timer_expired, CLOCK_MONOTONIC, + HRTIMER_MODE_REL); + } + cmd->error = BLK_STS_OK; + cmd->nq = nq; + cmd->fake_timeout = should_timeout_request(rq) || + blk_should_fake_timeout(rq->q); + + if (should_requeue_request(rq)) { + /* + * Alternate between hitting the core BUSY path, and the + * driver driven requeue path + */ + nq->requeue_selection++; + if (nq->requeue_selection & 1) + return BLK_STS_RESOURCE; + blk_mq_requeue_request(rq, true); + return BLK_STS_OK; + } + + if (test_bit(NULLB_DEV_FL_THROTTLED, &nq->dev->flags)) { + blk_status_t sts = null_handle_throttled(cmd); + + if (sts != BLK_STS_OK) + return sts; + } + + blk_mq_start_request(rq); + + if (is_poll) { + spin_lock(&nq->poll_lock); + list_add_tail(&rq->queuelist, &nq->poll_list); + spin_unlock(&nq->poll_lock); + return BLK_STS_OK; + } + if (cmd->fake_timeout) + return BLK_STS_OK; + + null_handle_cmd(cmd, sector, nr_sectors, req_op(rq)); + return BLK_STS_OK; +} + +static void null_queue_rqs(struct rq_list *rqlist) +{ + struct rq_list requeue_list = {}; + struct blk_mq_queue_data bd = { }; + blk_status_t ret; + + do { + struct request *rq = rq_list_pop(rqlist); + + bd.rq = rq; + ret = null_queue_rq(rq->mq_hctx, &bd); + if (ret != BLK_STS_OK) + rq_list_add_tail(&requeue_list, rq); + } while (!rq_list_empty(rqlist)); + + *rqlist = requeue_list; +} + +static void null_init_queue(struct nullb *nullb, struct nullb_queue *nq) +{ + nq->dev = nullb->dev; + INIT_LIST_HEAD(&nq->poll_list); + spin_lock_init(&nq->poll_lock); +} + +static int null_init_hctx(struct blk_mq_hw_ctx *hctx, void *driver_data, + unsigned int hctx_idx) +{ + struct nullb *nullb = hctx->queue->queuedata; + struct nullb_queue *nq; + + if (should_init_hctx_fail(nullb->dev)) + return -EFAULT; + + nq = &nullb->queues[hctx_idx]; + hctx->driver_data = nq; + null_init_queue(nullb, nq); + + return 0; +} + +static const struct blk_mq_ops null_mq_ops = { + .queue_rq = null_queue_rq, + .queue_rqs = null_queue_rqs, + .complete = null_complete_rq, + .timeout = null_timeout_rq, + .poll = null_poll, + .map_queues = null_map_queues, + .init_hctx = null_init_hctx, +}; + +static void null_del_dev(struct nullb *nullb) +{ + struct nullb_device *dev; + + if (!nullb) + return; + + dev = nullb->dev; + + ida_free(&nullb_indexes, nullb->index); + + list_del_init(&nullb->list); + + del_gendisk(nullb->disk); + + if (test_bit(NULLB_DEV_FL_THROTTLED, &nullb->dev->flags)) { + hrtimer_cancel(&nullb->bw_timer); + atomic_long_set(&nullb->cur_bytes, LONG_MAX); + blk_mq_start_stopped_hw_queues(nullb->q, true); + } + + put_disk(nullb->disk); + if (nullb->tag_set == &nullb->__tag_set) + blk_mq_free_tag_set(nullb->tag_set); + kfree(nullb->queues); + if (null_cache_active(nullb)) + null_free_device_storage(nullb->dev, true); + kfree(nullb); + dev->nullb = NULL; +} + +static void null_config_discard(struct nullb *nullb, struct queue_limits *lim) +{ + if (nullb->dev->discard == false) + return; + + if (!nullb->dev->memory_backed) { + nullb->dev->discard = false; + pr_info("discard option is ignored without memory backing\n"); + return; + } + + if (nullb->dev->zoned) { + nullb->dev->discard = false; + pr_info("discard option is ignored in zoned mode\n"); + return; + } + + lim->max_hw_discard_sectors = UINT_MAX >> 9; +} + +static const struct block_device_operations null_ops = { + .owner = THIS_MODULE, + .report_zones = null_report_zones, +}; + +static int setup_queues(struct nullb *nullb) +{ + int nqueues = nr_cpu_ids; + + if (g_poll_queues) + nqueues += g_poll_queues; + + nullb->queues = kcalloc(nqueues, sizeof(struct nullb_queue), + GFP_KERNEL); + if (!nullb->queues) + return -ENOMEM; + + return 0; +} + +static int null_init_tag_set(struct blk_mq_tag_set *set, int poll_queues) +{ + set->ops = &null_mq_ops; + set->cmd_size = sizeof(struct nullb_cmd); + set->timeout = 5 * HZ; + set->nr_maps = 1; + if (poll_queues) { + set->nr_hw_queues += poll_queues; + set->nr_maps += 2; + } + return blk_mq_alloc_tag_set(set); +} + +static int null_init_global_tag_set(void) +{ + int error; + + if (tag_set.ops) + return 0; + + tag_set.nr_hw_queues = g_submit_queues; + tag_set.queue_depth = g_hw_queue_depth; + tag_set.numa_node = g_home_node; + if (g_no_sched) + tag_set.flags |= BLK_MQ_F_NO_SCHED_BY_DEFAULT; + if (g_shared_tag_bitmap) + tag_set.flags |= BLK_MQ_F_TAG_HCTX_SHARED; + if (g_blocking) + tag_set.flags |= BLK_MQ_F_BLOCKING; + + error = null_init_tag_set(&tag_set, g_poll_queues); + if (error) + tag_set.ops = NULL; + return error; +} + +static int null_setup_tagset(struct nullb *nullb) +{ + if (nullb->dev->shared_tags) { + nullb->tag_set = &tag_set; + return null_init_global_tag_set(); + } + + nullb->tag_set = &nullb->__tag_set; + nullb->tag_set->driver_data = nullb; + nullb->tag_set->nr_hw_queues = nullb->dev->submit_queues; + nullb->tag_set->queue_depth = nullb->dev->hw_queue_depth; + nullb->tag_set->numa_node = nullb->dev->home_node; + if (nullb->dev->no_sched) + nullb->tag_set->flags |= BLK_MQ_F_NO_SCHED_BY_DEFAULT; + if (nullb->dev->shared_tag_bitmap) + nullb->tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED; + if (nullb->dev->blocking) + nullb->tag_set->flags |= BLK_MQ_F_BLOCKING; + return null_init_tag_set(nullb->tag_set, nullb->dev->poll_queues); +} + +static int null_validate_conf(struct nullb_device *dev) +{ + if (dev->queue_mode == NULL_Q_RQ) { + pr_err("legacy IO path is no longer available\n"); + return -EINVAL; + } + if (dev->queue_mode == NULL_Q_BIO) { + pr_err("BIO-based IO path is no longer available, using blk-mq instead.\n"); + dev->queue_mode = NULL_Q_MQ; + } + + if (dev->use_per_node_hctx) { + if (dev->submit_queues != nr_online_nodes) + dev->submit_queues = nr_online_nodes; + } else if (dev->submit_queues > nr_cpu_ids) + dev->submit_queues = nr_cpu_ids; + else if (dev->submit_queues == 0) + dev->submit_queues = 1; + dev->prev_submit_queues = dev->submit_queues; + + if (dev->poll_queues > g_poll_queues) + dev->poll_queues = g_poll_queues; + dev->prev_poll_queues = dev->poll_queues; + dev->irqmode = min_t(unsigned int, dev->irqmode, NULL_IRQ_TIMER); + + /* Do memory allocation, so set blocking */ + if (dev->memory_backed) + dev->blocking = true; + else /* cache is meaningless */ + dev->cache_size = 0; + dev->cache_size = min_t(unsigned long, ULONG_MAX / 1024 / 1024, + dev->cache_size); + dev->mbps = min_t(unsigned int, 1024 * 40, dev->mbps); + + if (dev->zoned && + (!dev->zone_size || !is_power_of_2(dev->zone_size))) { + pr_err("zone_size must be power-of-two\n"); + return -EINVAL; + } + + return 0; +} + +#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION +static bool __null_setup_fault(struct fault_attr *attr, char *str) +{ + if (!str[0]) + return true; + + if (!setup_fault_attr(attr, str)) + return false; + + attr->verbose = 0; + return true; +} +#endif + +static bool null_setup_fault(void) +{ +#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION + if (!__null_setup_fault(&null_timeout_attr, g_timeout_str)) + return false; + if (!__null_setup_fault(&null_requeue_attr, g_requeue_str)) + return false; + if (!__null_setup_fault(&null_init_hctx_attr, g_init_hctx_str)) + return false; +#endif + return true; +} + +static int null_add_dev(struct nullb_device *dev) +{ + struct queue_limits lim = { + .logical_block_size = dev->blocksize, + .physical_block_size = dev->blocksize, + .max_hw_sectors = dev->max_sectors, + .dma_alignment = 1, + }; + + struct nullb *nullb; + int rv; + + rv = null_validate_conf(dev); + if (rv) + return rv; + + nullb = kzalloc_node(sizeof(*nullb), GFP_KERNEL, dev->home_node); + if (!nullb) { + rv = -ENOMEM; + goto out; + } + nullb->dev = dev; + dev->nullb = nullb; + + spin_lock_init(&nullb->lock); + + rv = setup_queues(nullb); + if (rv) + goto out_free_nullb; + + rv = null_setup_tagset(nullb); + if (rv) + goto out_cleanup_queues; + + if (dev->virt_boundary) + lim.virt_boundary_mask = PAGE_SIZE - 1; + null_config_discard(nullb, &lim); + if (dev->zoned) { + rv = null_init_zoned_dev(dev, &lim); + if (rv) + goto out_cleanup_tags; + } + + if (dev->cache_size > 0) { + set_bit(NULLB_DEV_FL_CACHE, &nullb->dev->flags); + lim.features |= BLK_FEAT_WRITE_CACHE; + if (dev->fua) + lim.features |= BLK_FEAT_FUA; + } + + if (dev->rotational) + lim.features |= BLK_FEAT_ROTATIONAL; + + nullb->disk = blk_mq_alloc_disk(nullb->tag_set, &lim, nullb); + if (IS_ERR(nullb->disk)) { + rv = PTR_ERR(nullb->disk); + goto out_cleanup_zone; + } + nullb->q = nullb->disk->queue; + + if (dev->mbps) { + set_bit(NULLB_DEV_FL_THROTTLED, &dev->flags); + nullb_setup_bwtimer(nullb); + } + + nullb->q->queuedata = nullb; + + rv = ida_alloc(&nullb_indexes, GFP_KERNEL); + if (rv < 0) + goto out_cleanup_disk; + + nullb->index = rv; + dev->index = rv; + + if (config_item_name(&dev->group.cg_item)) { + /* Use configfs dir name as the device name */ + snprintf(nullb->disk_name, sizeof(nullb->disk_name), + "%s", config_item_name(&dev->group.cg_item)); + } else { + sprintf(nullb->disk_name, "nullb%d", nullb->index); + } + + set_capacity(nullb->disk, + ((sector_t)nullb->dev->size * SZ_1M) >> SECTOR_SHIFT); + nullb->disk->major = null_major; + nullb->disk->first_minor = nullb->index; + nullb->disk->minors = 1; + nullb->disk->fops = &null_ops; + nullb->disk->private_data = nullb; + strscpy(nullb->disk->disk_name, nullb->disk_name); + + if (nullb->dev->zoned) { + rv = null_register_zoned_dev(nullb); + if (rv) + goto out_ida_free; + } + + rv = add_disk(nullb->disk); + if (rv) + goto out_ida_free; + + list_add_tail(&nullb->list, &nullb_list); + + pr_info("disk %s created\n", nullb->disk_name); + + return 0; + +out_ida_free: + ida_free(&nullb_indexes, nullb->index); +out_cleanup_disk: + put_disk(nullb->disk); +out_cleanup_zone: + null_free_zoned_dev(dev); +out_cleanup_tags: + if (nullb->tag_set == &nullb->__tag_set) + blk_mq_free_tag_set(nullb->tag_set); +out_cleanup_queues: + kfree(nullb->queues); +out_free_nullb: + kfree(nullb); + dev->nullb = NULL; +out: + return rv; +} + +static struct nullb *null_find_dev_by_name(const char *name) +{ + struct nullb *nullb = NULL, *nb; + + mutex_lock(&lock); + list_for_each_entry(nb, &nullb_list, list) { + if (strcmp(nb->disk_name, name) == 0) { + nullb = nb; + break; + } + } + mutex_unlock(&lock); + + return nullb; +} + +static int null_create_dev(void) +{ + struct nullb_device *dev; + int ret; + + dev = null_alloc_dev(); + if (!dev) + return -ENOMEM; + + mutex_lock(&lock); + ret = null_add_dev(dev); + mutex_unlock(&lock); + if (ret) { + null_free_dev(dev); + return ret; + } + + return 0; +} + +static void null_destroy_dev(struct nullb *nullb) +{ + struct nullb_device *dev = nullb->dev; + + null_del_dev(nullb); + null_free_device_storage(dev, false); + null_free_dev(dev); +} + +static int __init null_init(void) +{ + int ret = 0; + unsigned int i; + struct nullb *nullb; + + if (g_bs > PAGE_SIZE) { + pr_warn("invalid block size\n"); + pr_warn("defaults block size to %lu\n", PAGE_SIZE); + g_bs = PAGE_SIZE; + } + + if (g_home_node != NUMA_NO_NODE && g_home_node >= nr_online_nodes) { + pr_err("invalid home_node value\n"); + g_home_node = NUMA_NO_NODE; + } + + if (!null_setup_fault()) + return -EINVAL; + + if (g_queue_mode == NULL_Q_RQ) { + pr_err("legacy IO path is no longer available\n"); + return -EINVAL; + } + + if (g_use_per_node_hctx) { + if (g_submit_queues != nr_online_nodes) { + pr_warn("submit_queues param is set to %u.\n", + nr_online_nodes); + g_submit_queues = nr_online_nodes; + } + } else if (g_submit_queues > nr_cpu_ids) { + g_submit_queues = nr_cpu_ids; + } else if (g_submit_queues <= 0) { + g_submit_queues = 1; + } + + config_group_init(&nullb_subsys.su_group); + mutex_init(&nullb_subsys.su_mutex); + + ret = configfs_register_subsystem(&nullb_subsys); + if (ret) + return ret; + + mutex_init(&lock); + + null_major = register_blkdev(0, "nullb"); + if (null_major < 0) { + ret = null_major; + goto err_conf; + } + + for (i = 0; i < nr_devices; i++) { + ret = null_create_dev(); + if (ret) + goto err_dev; + } + + pr_info("module loaded\n"); + return 0; + +err_dev: + while (!list_empty(&nullb_list)) { + nullb = list_entry(nullb_list.next, struct nullb, list); + null_destroy_dev(nullb); + } + unregister_blkdev(null_major, "nullb"); +err_conf: + configfs_unregister_subsystem(&nullb_subsys); + return ret; +} + +static void __exit null_exit(void) +{ + struct nullb *nullb; + + configfs_unregister_subsystem(&nullb_subsys); + + unregister_blkdev(null_major, "nullb"); + + mutex_lock(&lock); + while (!list_empty(&nullb_list)) { + nullb = list_entry(nullb_list.next, struct nullb, list); + null_destroy_dev(nullb); + } + mutex_unlock(&lock); + + if (tag_set.ops) + blk_mq_free_tag_set(&tag_set); + + mutex_destroy(&lock); +} + +module_init(null_init); +module_exit(null_exit); + +MODULE_AUTHOR("Jens Axboe <axboe@kernel.dk>"); +MODULE_DESCRIPTION("multi queue aware block test driver"); +MODULE_LICENSE("GPL"); |