diff options
Diffstat (limited to 'drivers/dma-buf/dma-buf.c')
| -rw-r--r-- | drivers/dma-buf/dma-buf.c | 1179 |
1 files changed, 753 insertions, 426 deletions
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 01ce125f8e8d..edaa9e4ee4ae 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -15,11 +15,15 @@ #include <linux/slab.h> #include <linux/dma-buf.h> #include <linux/dma-fence.h> +#include <linux/dma-fence-unwrap.h> #include <linux/anon_inodes.h> #include <linux/export.h> #include <linux/debugfs.h> +#include <linux/list.h> #include <linux/module.h> +#include <linux/mutex.h> #include <linux/seq_file.h> +#include <linux/sync_file.h> #include <linux/poll.h> #include <linux/dma-resv.h> #include <linux/mm.h> @@ -29,33 +33,154 @@ #include <uapi/linux/dma-buf.h> #include <uapi/linux/magic.h> +#include "dma-buf-sysfs-stats.h" + static inline int is_dma_buf_file(struct file *); -struct dma_buf_list { - struct list_head head; - struct mutex lock; -}; +static DEFINE_MUTEX(dmabuf_list_mutex); +static LIST_HEAD(dmabuf_list); + +static void __dma_buf_list_add(struct dma_buf *dmabuf) +{ + mutex_lock(&dmabuf_list_mutex); + list_add(&dmabuf->list_node, &dmabuf_list); + mutex_unlock(&dmabuf_list_mutex); +} + +static void __dma_buf_list_del(struct dma_buf *dmabuf) +{ + if (!dmabuf) + return; + + mutex_lock(&dmabuf_list_mutex); + list_del(&dmabuf->list_node); + mutex_unlock(&dmabuf_list_mutex); +} + +/** + * dma_buf_iter_begin - begin iteration through global list of all DMA buffers + * + * Returns the first buffer in the global list of DMA-bufs that's not in the + * process of being destroyed. Increments that buffer's reference count to + * prevent buffer destruction. Callers must release the reference, either by + * continuing iteration with dma_buf_iter_next(), or with dma_buf_put(). + * + * Return: + * * First buffer from global list, with refcount elevated + * * NULL if no active buffers are present + */ +struct dma_buf *dma_buf_iter_begin(void) +{ + struct dma_buf *ret = NULL, *dmabuf; -static struct dma_buf_list db_list; + /* + * The list mutex does not protect a dmabuf's refcount, so it can be + * zeroed while we are iterating. We cannot call get_dma_buf() since the + * caller may not already own a reference to the buffer. + */ + mutex_lock(&dmabuf_list_mutex); + list_for_each_entry(dmabuf, &dmabuf_list, list_node) { + if (file_ref_get(&dmabuf->file->f_ref)) { + ret = dmabuf; + break; + } + } + mutex_unlock(&dmabuf_list_mutex); + return ret; +} + +/** + * dma_buf_iter_next - continue iteration through global list of all DMA buffers + * @dmabuf: [in] pointer to dma_buf + * + * Decrements the reference count on the provided buffer. Returns the next + * buffer from the remainder of the global list of DMA-bufs with its reference + * count incremented. Callers must release the reference, either by continuing + * iteration with dma_buf_iter_next(), or with dma_buf_put(). + * + * Return: + * * Next buffer from global list, with refcount elevated + * * NULL if no additional active buffers are present + */ +struct dma_buf *dma_buf_iter_next(struct dma_buf *dmabuf) +{ + struct dma_buf *ret = NULL; + + /* + * The list mutex does not protect a dmabuf's refcount, so it can be + * zeroed while we are iterating. We cannot call get_dma_buf() since the + * caller may not already own a reference to the buffer. + */ + mutex_lock(&dmabuf_list_mutex); + dma_buf_put(dmabuf); + list_for_each_entry_continue(dmabuf, &dmabuf_list, list_node) { + if (file_ref_get(&dmabuf->file->f_ref)) { + ret = dmabuf; + break; + } + } + mutex_unlock(&dmabuf_list_mutex); + return ret; +} static char *dmabuffs_dname(struct dentry *dentry, char *buffer, int buflen) { struct dma_buf *dmabuf; char name[DMA_BUF_NAME_LEN]; - size_t ret = 0; + ssize_t ret = 0; dmabuf = dentry->d_fsdata; - dma_resv_lock(dmabuf->resv, NULL); + spin_lock(&dmabuf->name_lock); if (dmabuf->name) - ret = strlcpy(name, dmabuf->name, DMA_BUF_NAME_LEN); - dma_resv_unlock(dmabuf->resv); + ret = strscpy(name, dmabuf->name, sizeof(name)); + spin_unlock(&dmabuf->name_lock); - return dynamic_dname(dentry, buffer, buflen, "/%s:%s", + return dynamic_dname(buffer, buflen, "/%s:%s", dentry->d_name.name, ret > 0 ? name : ""); } +static void dma_buf_release(struct dentry *dentry) +{ + struct dma_buf *dmabuf; + + dmabuf = dentry->d_fsdata; + if (unlikely(!dmabuf)) + return; + + BUG_ON(dmabuf->vmapping_counter); + + /* + * If you hit this BUG() it could mean: + * * There's a file reference imbalance in dma_buf_poll / dma_buf_poll_cb or somewhere else + * * dmabuf->cb_in/out.active are non-0 despite no pending fence callback + */ + BUG_ON(dmabuf->cb_in.active || dmabuf->cb_out.active); + + dma_buf_stats_teardown(dmabuf); + dmabuf->ops->release(dmabuf); + + if (dmabuf->resv == (struct dma_resv *)&dmabuf[1]) + dma_resv_fini(dmabuf->resv); + + WARN_ON(!list_empty(&dmabuf->attachments)); + module_put(dmabuf->owner); + kfree(dmabuf->name); + kfree(dmabuf); +} + +static int dma_buf_file_release(struct inode *inode, struct file *file) +{ + if (!is_dma_buf_file(file)) + return -EINVAL; + + __dma_buf_list_del(file->private_data); + + return 0; +} + static const struct dentry_operations dma_buf_dentry_ops = { .d_dname = dmabuffs_dname, + .d_release = dma_buf_release, }; static struct vfsmount *dma_buf_mnt; @@ -77,42 +202,6 @@ static struct file_system_type dma_buf_fs_type = { .kill_sb = kill_anon_super, }; -static int dma_buf_release(struct inode *inode, struct file *file) -{ - struct dma_buf *dmabuf; - - if (!is_dma_buf_file(file)) - return -EINVAL; - - dmabuf = file->private_data; - - BUG_ON(dmabuf->vmapping_counter); - - /* - * Any fences that a dma-buf poll can wait on should be signaled - * before releasing dma-buf. This is the responsibility of each - * driver that uses the reservation objects. - * - * If you hit this BUG() it means someone dropped their ref to the - * dma-buf while still having pending operation to the buffer. - */ - BUG_ON(dmabuf->cb_shared.active || dmabuf->cb_excl.active); - - dmabuf->ops->release(dmabuf); - - mutex_lock(&db_list.lock); - list_del(&dmabuf->list_node); - mutex_unlock(&db_list.lock); - - if (dmabuf->resv == (struct dma_resv *)&dmabuf[1]) - dma_resv_fini(dmabuf->resv); - - module_put(dmabuf->owner); - kfree(dmabuf->name); - kfree(dmabuf); - return 0; -} - static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma) { struct dma_buf *dmabuf; @@ -145,8 +234,9 @@ static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence) dmabuf = file->private_data; /* only support discovering the end of the buffer, - but also allow SEEK_SET to maintain the idiomatic - SEEK_END(0), SEEK_CUR(0) pattern */ + * but also allow SEEK_SET to maintain the idiomatic + * SEEK_END(0), SEEK_CUR(0) pattern. + */ if (whence == SEEK_END) base = dmabuf->size; else if (whence == SEEK_SET) @@ -161,11 +251,11 @@ static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence) } /** - * DOC: fence polling + * DOC: implicit fence polling * * To support cross-device and cross-driver synchronization of buffer access - * implicit fences (represented internally in the kernel with &struct fence) can - * be attached to a &dma_buf. The glue for that and a few related things are + * implicit fences (represented internally in the kernel with &struct dma_fence) + * can be attached to a &dma_buf. The glue for that and a few related things are * provided in the &dma_resv structure. * * Userspace can query the state of these implicitly tracked fences using poll() @@ -180,27 +270,50 @@ static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence) * Note that this only signals the completion of the respective fences, i.e. the * DMA transfers are complete. Cache flushing and any other necessary * preparations before CPU access can begin still need to happen. + * + * As an alternative to poll(), the set of fences on DMA buffer can be + * exported as a &sync_file using &dma_buf_sync_file_export. */ static void dma_buf_poll_cb(struct dma_fence *fence, struct dma_fence_cb *cb) { struct dma_buf_poll_cb_t *dcb = (struct dma_buf_poll_cb_t *)cb; + struct dma_buf *dmabuf = container_of(dcb->poll, struct dma_buf, poll); unsigned long flags; spin_lock_irqsave(&dcb->poll->lock, flags); wake_up_locked_poll(dcb->poll, dcb->active); dcb->active = 0; spin_unlock_irqrestore(&dcb->poll->lock, flags); + dma_fence_put(fence); + /* Paired with get_file in dma_buf_poll */ + fput(dmabuf->file); +} + +static bool dma_buf_poll_add_cb(struct dma_resv *resv, bool write, + struct dma_buf_poll_cb_t *dcb) +{ + struct dma_resv_iter cursor; + struct dma_fence *fence; + int r; + + dma_resv_for_each_fence(&cursor, resv, dma_resv_usage_rw(write), + fence) { + dma_fence_get(fence); + r = dma_fence_add_callback(fence, &dcb->cb, dma_buf_poll_cb); + if (!r) + return true; + dma_fence_put(fence); + } + + return false; } static __poll_t dma_buf_poll(struct file *file, poll_table *poll) { struct dma_buf *dmabuf; struct dma_resv *resv; - struct dma_resv_list *fobj; - struct dma_fence *fence_excl; __poll_t events; - unsigned shared_count, seq; dmabuf = file->private_data; if (!dmabuf || !dmabuf->resv) @@ -214,114 +327,66 @@ static __poll_t dma_buf_poll(struct file *file, poll_table *poll) if (!events) return 0; -retry: - seq = read_seqcount_begin(&resv->seq); - rcu_read_lock(); + dma_resv_lock(resv, NULL); - fobj = rcu_dereference(resv->fence); - if (fobj) - shared_count = fobj->shared_count; - else - shared_count = 0; - fence_excl = rcu_dereference(resv->fence_excl); - if (read_seqcount_retry(&resv->seq, seq)) { - rcu_read_unlock(); - goto retry; - } - - if (fence_excl && (!(events & EPOLLOUT) || shared_count == 0)) { - struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_excl; - __poll_t pevents = EPOLLIN; - - if (shared_count == 0) - pevents |= EPOLLOUT; + if (events & EPOLLOUT) { + struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_out; + /* Check that callback isn't busy */ spin_lock_irq(&dmabuf->poll.lock); - if (dcb->active) { - dcb->active |= pevents; - events &= ~pevents; - } else - dcb->active = pevents; + if (dcb->active) + events &= ~EPOLLOUT; + else + dcb->active = EPOLLOUT; spin_unlock_irq(&dmabuf->poll.lock); - if (events & pevents) { - if (!dma_fence_get_rcu(fence_excl)) { - /* force a recheck */ - events &= ~pevents; - dma_buf_poll_cb(NULL, &dcb->cb); - } else if (!dma_fence_add_callback(fence_excl, &dcb->cb, - dma_buf_poll_cb)) { - events &= ~pevents; - dma_fence_put(fence_excl); - } else { - /* - * No callback queued, wake up any additional - * waiters. - */ - dma_fence_put(fence_excl); + if (events & EPOLLOUT) { + /* Paired with fput in dma_buf_poll_cb */ + get_file(dmabuf->file); + + if (!dma_buf_poll_add_cb(resv, true, dcb)) + /* No callback queued, wake up any other waiters */ dma_buf_poll_cb(NULL, &dcb->cb); - } + else + events &= ~EPOLLOUT; } } - if ((events & EPOLLOUT) && shared_count > 0) { - struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_shared; - int i; + if (events & EPOLLIN) { + struct dma_buf_poll_cb_t *dcb = &dmabuf->cb_in; - /* Only queue a new callback if no event has fired yet */ + /* Check that callback isn't busy */ spin_lock_irq(&dmabuf->poll.lock); if (dcb->active) - events &= ~EPOLLOUT; + events &= ~EPOLLIN; else - dcb->active = EPOLLOUT; + dcb->active = EPOLLIN; spin_unlock_irq(&dmabuf->poll.lock); - if (!(events & EPOLLOUT)) - goto out; - - for (i = 0; i < shared_count; ++i) { - struct dma_fence *fence = rcu_dereference(fobj->shared[i]); + if (events & EPOLLIN) { + /* Paired with fput in dma_buf_poll_cb */ + get_file(dmabuf->file); - if (!dma_fence_get_rcu(fence)) { - /* - * fence refcount dropped to zero, this means - * that fobj has been freed - * - * call dma_buf_poll_cb and force a recheck! - */ - events &= ~EPOLLOUT; + if (!dma_buf_poll_add_cb(resv, false, dcb)) + /* No callback queued, wake up any other waiters */ dma_buf_poll_cb(NULL, &dcb->cb); - break; - } - if (!dma_fence_add_callback(fence, &dcb->cb, - dma_buf_poll_cb)) { - dma_fence_put(fence); - events &= ~EPOLLOUT; - break; - } - dma_fence_put(fence); + else + events &= ~EPOLLIN; } - - /* No callback queued, wake up any additional waiters. */ - if (i == shared_count) - dma_buf_poll_cb(NULL, &dcb->cb); } -out: - rcu_read_unlock(); + dma_resv_unlock(resv); return events; } /** * dma_buf_set_name - Set a name to a specific dma_buf to track the usage. - * The name of the dma-buf buffer can only be set when the dma-buf is not - * attached to any devices. It could theoritically support changing the - * name of the dma-buf if the same piece of memory is used for multiple - * purpose between different devices. + * It could support changing the name of the dma-buf if the same + * piece of memory is used for multiple purpose between different devices. * - * @dmabuf [in] dmabuf buffer that will be renamed. - * @buf: [in] A piece of userspace memory that contains the name of - * the dma-buf. + * @dmabuf: [in] dmabuf buffer that will be renamed. + * @buf: [in] A piece of userspace memory that contains the name of + * the dma-buf. * * Returns 0 on success. If the dma-buf buffer is already attached to * devices, return -EBUSY. @@ -330,24 +395,122 @@ out: static long dma_buf_set_name(struct dma_buf *dmabuf, const char __user *buf) { char *name = strndup_user(buf, DMA_BUF_NAME_LEN); - long ret = 0; if (IS_ERR(name)) return PTR_ERR(name); - dma_resv_lock(dmabuf->resv, NULL); - if (!list_empty(&dmabuf->attachments)) { - ret = -EBUSY; - kfree(name); - goto out_unlock; - } + spin_lock(&dmabuf->name_lock); kfree(dmabuf->name); dmabuf->name = name; + spin_unlock(&dmabuf->name_lock); + + return 0; +} + +#if IS_ENABLED(CONFIG_SYNC_FILE) +static long dma_buf_export_sync_file(struct dma_buf *dmabuf, + void __user *user_data) +{ + struct dma_buf_export_sync_file arg; + enum dma_resv_usage usage; + struct dma_fence *fence = NULL; + struct sync_file *sync_file; + int fd, ret; + + if (copy_from_user(&arg, user_data, sizeof(arg))) + return -EFAULT; + + if (arg.flags & ~DMA_BUF_SYNC_RW) + return -EINVAL; + + if ((arg.flags & DMA_BUF_SYNC_RW) == 0) + return -EINVAL; + + fd = get_unused_fd_flags(O_CLOEXEC); + if (fd < 0) + return fd; + + usage = dma_resv_usage_rw(arg.flags & DMA_BUF_SYNC_WRITE); + ret = dma_resv_get_singleton(dmabuf->resv, usage, &fence); + if (ret) + goto err_put_fd; + + if (!fence) + fence = dma_fence_get_stub(); + + sync_file = sync_file_create(fence); + + dma_fence_put(fence); + + if (!sync_file) { + ret = -ENOMEM; + goto err_put_fd; + } + + arg.fd = fd; + if (copy_to_user(user_data, &arg, sizeof(arg))) { + ret = -EFAULT; + goto err_put_file; + } + + fd_install(fd, sync_file->file); + + return 0; + +err_put_file: + fput(sync_file->file); +err_put_fd: + put_unused_fd(fd); + return ret; +} + +static long dma_buf_import_sync_file(struct dma_buf *dmabuf, + const void __user *user_data) +{ + struct dma_buf_import_sync_file arg; + struct dma_fence *fence, *f; + enum dma_resv_usage usage; + struct dma_fence_unwrap iter; + unsigned int num_fences; + int ret = 0; + + if (copy_from_user(&arg, user_data, sizeof(arg))) + return -EFAULT; + + if (arg.flags & ~DMA_BUF_SYNC_RW) + return -EINVAL; + + if ((arg.flags & DMA_BUF_SYNC_RW) == 0) + return -EINVAL; + + fence = sync_file_get_fence(arg.fd); + if (!fence) + return -EINVAL; + + usage = (arg.flags & DMA_BUF_SYNC_WRITE) ? DMA_RESV_USAGE_WRITE : + DMA_RESV_USAGE_READ; + + num_fences = 0; + dma_fence_unwrap_for_each(f, &iter, fence) + ++num_fences; + + if (num_fences > 0) { + dma_resv_lock(dmabuf->resv, NULL); + + ret = dma_resv_reserve_fences(dmabuf->resv, num_fences); + if (!ret) { + dma_fence_unwrap_for_each(f, &iter, fence) + dma_resv_add_fence(dmabuf->resv, f, usage); + } + + dma_resv_unlock(dmabuf->resv); + } + + dma_fence_put(fence); -out_unlock: - dma_resv_unlock(dmabuf->resv); return ret; } +#endif static long dma_buf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) @@ -392,6 +555,13 @@ static long dma_buf_ioctl(struct file *file, case DMA_BUF_SET_NAME_B: return dma_buf_set_name(dmabuf, (const char __user *)arg); +#if IS_ENABLED(CONFIG_SYNC_FILE) + case DMA_BUF_IOCTL_EXPORT_SYNC_FILE: + return dma_buf_export_sync_file(dmabuf, (void __user *)arg); + case DMA_BUF_IOCTL_IMPORT_SYNC_FILE: + return dma_buf_import_sync_file(dmabuf, (const void __user *)arg); +#endif + default: return -ENOTTY; } @@ -405,14 +575,14 @@ static void dma_buf_show_fdinfo(struct seq_file *m, struct file *file) /* Don't count the temporary reference taken inside procfs seq_show */ seq_printf(m, "count:\t%ld\n", file_count(dmabuf->file) - 1); seq_printf(m, "exp_name:\t%s\n", dmabuf->exp_name); - dma_resv_lock(dmabuf->resv, NULL); + spin_lock(&dmabuf->name_lock); if (dmabuf->name) seq_printf(m, "name:\t%s\n", dmabuf->name); - dma_resv_unlock(dmabuf->resv); + spin_unlock(&dmabuf->name_lock); } static const struct file_operations dma_buf_fops = { - .release = dma_buf_release, + .release = dma_buf_file_release, .mmap = dma_buf_mmap_internal, .llseek = dma_buf_llseek, .poll = dma_buf_poll, @@ -429,24 +599,30 @@ static inline int is_dma_buf_file(struct file *file) return file->f_op == &dma_buf_fops; } -static struct file *dma_buf_getfile(struct dma_buf *dmabuf, int flags) +static struct file *dma_buf_getfile(size_t size, int flags) { - struct file *file; + static atomic64_t dmabuf_inode = ATOMIC64_INIT(0); struct inode *inode = alloc_anon_inode(dma_buf_mnt->mnt_sb); + struct file *file; if (IS_ERR(inode)) return ERR_CAST(inode); - inode->i_size = dmabuf->size; - inode_set_bytes(inode, dmabuf->size); + inode->i_size = size; + inode_set_bytes(inode, size); + /* + * The ->i_ino acquired from get_next_ino() is not unique thus + * not suitable for using it as dentry name by dmabuf stats. + * Override ->i_ino with the unique and dmabuffs specific + * value. + */ + inode->i_ino = atomic64_inc_return(&dmabuf_inode); + flags &= O_ACCMODE | O_NONBLOCK; file = alloc_file_pseudo(inode, dma_buf_mnt, "dmabuf", flags, &dma_buf_fops); if (IS_ERR(file)) goto err_alloc_file; - file->f_flags = flags & (O_ACCMODE | O_NONBLOCK); - file->private_data = dmabuf; - file->f_path.dentry->d_fsdata = dmabuf; return file; @@ -467,7 +643,7 @@ err_alloc_file: * as a file descriptor by calling dma_buf_fd(). * * 2. Userspace passes this file-descriptors to all drivers it wants this buffer - * to share with: First the filedescriptor is converted to a &dma_buf using + * to share with: First the file descriptor is converted to a &dma_buf using * dma_buf_get(). Then the buffer is attached to the device using * dma_buf_attach(). * @@ -480,7 +656,7 @@ err_alloc_file: * * 4. Once a driver is done with a shared buffer it needs to call * dma_buf_detach() (after cleaning up any mappings) and then release the - * reference acquired with dma_buf_get by calling dma_buf_put(). + * reference acquired with dma_buf_get() by calling dma_buf_put(). * * For the detailed semantics exporters are expected to implement see * &dma_buf_ops. @@ -496,9 +672,10 @@ err_alloc_file: * by the exporter. see &struct dma_buf_export_info * for further details. * - * Returns, on success, a newly created dma_buf object, which wraps the - * supplied private data and operations for dma_buf_ops. On either missing - * ops, or error in allocating struct dma_buf, will return negative error. + * Returns, on success, a newly created struct dma_buf object, which wraps the + * supplied private data and operations for struct dma_buf_ops. On either + * missing ops, or error in allocating struct dma_buf, will return negative + * error. * * For most cases the easiest way to create @exp_info is through the * %DEFINE_DMA_BUF_EXPORT_INFO macro. @@ -511,22 +688,10 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) size_t alloc_size = sizeof(struct dma_buf); int ret; - if (!exp_info->resv) - alloc_size += sizeof(struct dma_resv); - else - /* prevent &dma_buf[1] == dma_buf->resv */ - alloc_size += 1; - - if (WARN_ON(!exp_info->priv - || !exp_info->ops - || !exp_info->ops->map_dma_buf - || !exp_info->ops->unmap_dma_buf - || !exp_info->ops->release)) { - return ERR_PTR(-EINVAL); - } - - if (WARN_ON(exp_info->ops->cache_sgt_mapping && - (exp_info->ops->pin || exp_info->ops->unpin))) + if (WARN_ON(!exp_info->priv || !exp_info->ops + || !exp_info->ops->map_dma_buf + || !exp_info->ops->unmap_dma_buf + || !exp_info->ops->release)) return ERR_PTR(-EINVAL); if (WARN_ON(!exp_info->ops->pin != !exp_info->ops->unpin)) @@ -535,10 +700,21 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) if (!try_module_get(exp_info->owner)) return ERR_PTR(-ENOENT); + file = dma_buf_getfile(exp_info->size, exp_info->flags); + if (IS_ERR(file)) { + ret = PTR_ERR(file); + goto err_module; + } + + if (!exp_info->resv) + alloc_size += sizeof(struct dma_resv); + else + /* prevent &dma_buf[1] == dma_buf->resv */ + alloc_size += 1; dmabuf = kzalloc(alloc_size, GFP_KERNEL); if (!dmabuf) { ret = -ENOMEM; - goto err_module; + goto err_file; } dmabuf->priv = exp_info->priv; @@ -546,44 +722,45 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) dmabuf->size = exp_info->size; dmabuf->exp_name = exp_info->exp_name; dmabuf->owner = exp_info->owner; + spin_lock_init(&dmabuf->name_lock); init_waitqueue_head(&dmabuf->poll); - dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll; - dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0; + dmabuf->cb_in.poll = dmabuf->cb_out.poll = &dmabuf->poll; + dmabuf->cb_in.active = dmabuf->cb_out.active = 0; + INIT_LIST_HEAD(&dmabuf->attachments); if (!resv) { - resv = (struct dma_resv *)&dmabuf[1]; - dma_resv_init(resv); + dmabuf->resv = (struct dma_resv *)&dmabuf[1]; + dma_resv_init(dmabuf->resv); + } else { + dmabuf->resv = resv; } - dmabuf->resv = resv; - file = dma_buf_getfile(dmabuf, exp_info->flags); - if (IS_ERR(file)) { - ret = PTR_ERR(file); + ret = dma_buf_stats_setup(dmabuf, file); + if (ret) goto err_dmabuf; - } - file->f_mode |= FMODE_LSEEK; + file->private_data = dmabuf; + file->f_path.dentry->d_fsdata = dmabuf; dmabuf->file = file; - mutex_init(&dmabuf->lock); - INIT_LIST_HEAD(&dmabuf->attachments); - - mutex_lock(&db_list.lock); - list_add(&dmabuf->list_node, &db_list.head); - mutex_unlock(&db_list.lock); + __dma_buf_list_add(dmabuf); return dmabuf; err_dmabuf: + if (!resv) + dma_resv_fini(dmabuf->resv); kfree(dmabuf); +err_file: + fput(file); err_module: module_put(exp_info->owner); return ERR_PTR(ret); } -EXPORT_SYMBOL_GPL(dma_buf_export); +EXPORT_SYMBOL_NS_GPL(dma_buf_export, "DMA_BUF"); /** - * dma_buf_fd - returns a file descriptor for the given dma_buf + * dma_buf_fd - returns a file descriptor for the given struct dma_buf * @dmabuf: [in] pointer to dma_buf for which fd is required. * @flags: [in] flags to give to fd * @@ -591,26 +768,18 @@ EXPORT_SYMBOL_GPL(dma_buf_export); */ int dma_buf_fd(struct dma_buf *dmabuf, int flags) { - int fd; - if (!dmabuf || !dmabuf->file) return -EINVAL; - fd = get_unused_fd_flags(flags); - if (fd < 0) - return fd; - - fd_install(fd, dmabuf->file); - - return fd; + return FD_ADD(flags, dmabuf->file); } -EXPORT_SYMBOL_GPL(dma_buf_fd); +EXPORT_SYMBOL_NS_GPL(dma_buf_fd, "DMA_BUF"); /** - * dma_buf_get - returns the dma_buf structure related to an fd - * @fd: [in] fd associated with the dma_buf to be returned + * dma_buf_get - returns the struct dma_buf related to an fd + * @fd: [in] fd associated with the struct dma_buf to be returned * - * On success, returns the dma_buf structure associated with an fd; uses + * On success, returns the struct dma_buf associated with an fd; uses * file's refcounting done by fget to increase refcount. returns ERR_PTR * otherwise. */ @@ -630,7 +799,7 @@ struct dma_buf *dma_buf_get(int fd) return file->private_data; } -EXPORT_SYMBOL_GPL(dma_buf_get); +EXPORT_SYMBOL_NS_GPL(dma_buf_get, "DMA_BUF"); /** * dma_buf_put - decreases refcount of the buffer @@ -649,11 +818,105 @@ void dma_buf_put(struct dma_buf *dmabuf) fput(dmabuf->file); } -EXPORT_SYMBOL_GPL(dma_buf_put); +EXPORT_SYMBOL_NS_GPL(dma_buf_put, "DMA_BUF"); + +static void mangle_sg_table(struct sg_table *sg_table) +{ +#ifdef CONFIG_DMABUF_DEBUG + int i; + struct scatterlist *sg; + + /* To catch abuse of the underlying struct page by importers mix + * up the bits, but take care to preserve the low SG_ bits to + * not corrupt the sgt. The mixing is undone on unmap + * before passing the sgt back to the exporter. + */ + for_each_sgtable_sg(sg_table, sg, i) + sg->page_link ^= ~0xffUL; +#endif + +} + +static inline bool +dma_buf_attachment_is_dynamic(struct dma_buf_attachment *attach) +{ + return !!attach->importer_ops; +} + +static bool +dma_buf_pin_on_map(struct dma_buf_attachment *attach) +{ + return attach->dmabuf->ops->pin && + (!dma_buf_attachment_is_dynamic(attach) || + !IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY)); +} + +/** + * DOC: locking convention + * + * In order to avoid deadlock situations between dma-buf exports and importers, + * all dma-buf API users must follow the common dma-buf locking convention. + * + * Convention for importers + * + * 1. Importers must hold the dma-buf reservation lock when calling these + * functions: + * + * - dma_buf_pin() + * - dma_buf_unpin() + * - dma_buf_map_attachment() + * - dma_buf_unmap_attachment() + * - dma_buf_vmap() + * - dma_buf_vunmap() + * + * 2. Importers must not hold the dma-buf reservation lock when calling these + * functions: + * + * - dma_buf_attach() + * - dma_buf_dynamic_attach() + * - dma_buf_detach() + * - dma_buf_export() + * - dma_buf_fd() + * - dma_buf_get() + * - dma_buf_put() + * - dma_buf_mmap() + * - dma_buf_begin_cpu_access() + * - dma_buf_end_cpu_access() + * - dma_buf_map_attachment_unlocked() + * - dma_buf_unmap_attachment_unlocked() + * - dma_buf_vmap_unlocked() + * - dma_buf_vunmap_unlocked() + * + * Convention for exporters + * + * 1. These &dma_buf_ops callbacks are invoked with unlocked dma-buf + * reservation and exporter can take the lock: + * + * - &dma_buf_ops.attach() + * - &dma_buf_ops.detach() + * - &dma_buf_ops.release() + * - &dma_buf_ops.begin_cpu_access() + * - &dma_buf_ops.end_cpu_access() + * - &dma_buf_ops.mmap() + * + * 2. These &dma_buf_ops callbacks are invoked with locked dma-buf + * reservation and exporter can't take the lock: + * + * - &dma_buf_ops.pin() + * - &dma_buf_ops.unpin() + * - &dma_buf_ops.map_dma_buf() + * - &dma_buf_ops.unmap_dma_buf() + * - &dma_buf_ops.vmap() + * - &dma_buf_ops.vunmap() + * + * 3. Exporters must hold the dma-buf reservation lock when calling these + * functions: + * + * - dma_buf_move_notify() + */ /** - * dma_buf_dynamic_attach - Add the device to dma_buf's attachments list; optionally, - * calls attach() of dma_buf_ops to allow device-specific attach functionality + * dma_buf_dynamic_attach - Add the device to dma_buf's attachments list * @dmabuf: [in] buffer to attach device to. * @dev: [in] device to be attached. * @importer_ops: [in] importer operations for the attachment @@ -662,6 +925,9 @@ EXPORT_SYMBOL_GPL(dma_buf_put); * Returns struct dma_buf_attachment pointer for this attachment. Attachments * must be cleaned up by calling dma_buf_detach(). * + * Optionally this calls &dma_buf_ops.attach to allow device-specific attach + * functionality. + * * Returns: * * A pointer to newly created &dma_buf_attachment on success, or a negative @@ -705,52 +971,13 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, list_add(&attach->node, &dmabuf->attachments); dma_resv_unlock(dmabuf->resv); - /* When either the importer or the exporter can't handle dynamic - * mappings we cache the mapping here to avoid issues with the - * reservation object lock. - */ - if (dma_buf_attachment_is_dynamic(attach) != - dma_buf_is_dynamic(dmabuf)) { - struct sg_table *sgt; - - if (dma_buf_is_dynamic(attach->dmabuf)) { - dma_resv_lock(attach->dmabuf->resv, NULL); - ret = dma_buf_pin(attach); - if (ret) - goto err_unlock; - } - - sgt = dmabuf->ops->map_dma_buf(attach, DMA_BIDIRECTIONAL); - if (!sgt) - sgt = ERR_PTR(-ENOMEM); - if (IS_ERR(sgt)) { - ret = PTR_ERR(sgt); - goto err_unpin; - } - if (dma_buf_is_dynamic(attach->dmabuf)) - dma_resv_unlock(attach->dmabuf->resv); - attach->sgt = sgt; - attach->dir = DMA_BIDIRECTIONAL; - } - return attach; err_attach: kfree(attach); return ERR_PTR(ret); - -err_unpin: - if (dma_buf_is_dynamic(attach->dmabuf)) - dma_buf_unpin(attach); - -err_unlock: - if (dma_buf_is_dynamic(attach->dmabuf)) - dma_resv_unlock(attach->dmabuf->resv); - - dma_buf_detach(dmabuf, attach); - return ERR_PTR(ret); } -EXPORT_SYMBOL_GPL(dma_buf_dynamic_attach); +EXPORT_SYMBOL_NS_GPL(dma_buf_dynamic_attach, "DMA_BUF"); /** * dma_buf_attach - Wrapper for dma_buf_dynamic_attach @@ -765,48 +992,44 @@ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, { return dma_buf_dynamic_attach(dmabuf, dev, NULL, NULL); } -EXPORT_SYMBOL_GPL(dma_buf_attach); +EXPORT_SYMBOL_NS_GPL(dma_buf_attach, "DMA_BUF"); /** - * dma_buf_detach - Remove the given attachment from dmabuf's attachments list; - * optionally calls detach() of dma_buf_ops for device-specific detach + * dma_buf_detach - Remove the given attachment from dmabuf's attachments list * @dmabuf: [in] buffer to detach from. * @attach: [in] attachment to be detached; is free'd after this call. * * Clean up a device attachment obtained by calling dma_buf_attach(). + * + * Optionally this calls &dma_buf_ops.detach for device-specific detach. */ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) { - if (WARN_ON(!dmabuf || !attach)) + if (WARN_ON(!dmabuf || !attach || dmabuf != attach->dmabuf)) return; - if (attach->sgt) { - if (dma_buf_is_dynamic(attach->dmabuf)) - dma_resv_lock(attach->dmabuf->resv, NULL); - - dmabuf->ops->unmap_dma_buf(attach, attach->sgt, attach->dir); - - if (dma_buf_is_dynamic(attach->dmabuf)) { - dma_buf_unpin(attach); - dma_resv_unlock(attach->dmabuf->resv); - } - } - dma_resv_lock(dmabuf->resv, NULL); list_del(&attach->node); dma_resv_unlock(dmabuf->resv); + if (dmabuf->ops->detach) dmabuf->ops->detach(dmabuf, attach); kfree(attach); } -EXPORT_SYMBOL_GPL(dma_buf_detach); +EXPORT_SYMBOL_NS_GPL(dma_buf_detach, "DMA_BUF"); /** * dma_buf_pin - Lock down the DMA-buf - * * @attach: [in] attachment which should be pinned * + * Only dynamic importers (who set up @attach with dma_buf_dynamic_attach()) may + * call this, and only for limited use cases like scanout and not for temporary + * pin operations. It is not permitted to allow userspace to pin arbitrary + * amounts of buffers through this interface. + * + * Buffers must be unpinned by calling dma_buf_unpin(). + * * Returns: * 0 on success, negative error code on failure. */ @@ -815,6 +1038,8 @@ int dma_buf_pin(struct dma_buf_attachment *attach) struct dma_buf *dmabuf = attach->dmabuf; int ret = 0; + WARN_ON(!attach->importer_ops); + dma_resv_assert_held(dmabuf->resv); if (dmabuf->ops->pin) @@ -822,23 +1047,28 @@ int dma_buf_pin(struct dma_buf_attachment *attach) return ret; } -EXPORT_SYMBOL_GPL(dma_buf_pin); +EXPORT_SYMBOL_NS_GPL(dma_buf_pin, "DMA_BUF"); /** - * dma_buf_unpin - Remove lock from DMA-buf - * + * dma_buf_unpin - Unpin a DMA-buf * @attach: [in] attachment which should be unpinned + * + * This unpins a buffer pinned by dma_buf_pin() and allows the exporter to move + * any mapping of @attach again and inform the importer through + * &dma_buf_attach_ops.move_notify. */ void dma_buf_unpin(struct dma_buf_attachment *attach) { struct dma_buf *dmabuf = attach->dmabuf; + WARN_ON(!attach->importer_ops); + dma_resv_assert_held(dmabuf->resv); if (dmabuf->ops->unpin) dmabuf->ops->unpin(attach); } -EXPORT_SYMBOL_GPL(dma_buf_unpin); +EXPORT_SYMBOL_NS_GPL(dma_buf_unpin, "DMA_BUF"); /** * dma_buf_map_attachment - Returns the scatterlist table of the attachment; @@ -850,62 +1080,117 @@ EXPORT_SYMBOL_GPL(dma_buf_unpin); * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR * on error. May return -EINTR if it is interrupted by a signal. * + * On success, the DMA addresses and lengths in the returned scatterlist are + * PAGE_SIZE aligned. + * * A mapping must be unmapped by using dma_buf_unmap_attachment(). Note that * the underlying backing storage is pinned for as long as a mapping exists, * therefore users/importers should not hold onto a mapping for undue amounts of * time. + * + * Important: Dynamic importers must wait for the exclusive fence of the struct + * dma_resv attached to the DMA-BUF first. */ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, enum dma_data_direction direction) { struct sg_table *sg_table; - int r; + signed long ret; might_sleep(); if (WARN_ON(!attach || !attach->dmabuf)) return ERR_PTR(-EINVAL); - if (dma_buf_attachment_is_dynamic(attach)) - dma_resv_assert_held(attach->dmabuf->resv); + dma_resv_assert_held(attach->dmabuf->resv); - if (attach->sgt) { + if (dma_buf_pin_on_map(attach)) { + ret = attach->dmabuf->ops->pin(attach); /* - * Two mappings with different directions for the same - * attachment are not allowed. + * Catch exporters making buffers inaccessible even when + * attachments preventing that exist. */ - if (attach->dir != direction && - attach->dir != DMA_BIDIRECTIONAL) - return ERR_PTR(-EBUSY); - - return attach->sgt; - } - - if (dma_buf_is_dynamic(attach->dmabuf)) { - dma_resv_assert_held(attach->dmabuf->resv); - if (!IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY)) { - r = dma_buf_pin(attach); - if (r) - return ERR_PTR(r); - } + WARN_ON_ONCE(ret == -EBUSY); + if (ret) + return ERR_PTR(ret); } sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction); if (!sg_table) sg_table = ERR_PTR(-ENOMEM); + if (IS_ERR(sg_table)) + goto error_unpin; + + /* + * Importers with static attachments don't wait for fences. + */ + if (!dma_buf_attachment_is_dynamic(attach)) { + ret = dma_resv_wait_timeout(attach->dmabuf->resv, + DMA_RESV_USAGE_KERNEL, true, + MAX_SCHEDULE_TIMEOUT); + if (ret < 0) + goto error_unmap; + } + mangle_sg_table(sg_table); - if (IS_ERR(sg_table) && dma_buf_is_dynamic(attach->dmabuf) && - !IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY)) - dma_buf_unpin(attach); +#ifdef CONFIG_DMA_API_DEBUG + { + struct scatterlist *sg; + u64 addr; + int len; + int i; - if (!IS_ERR(sg_table) && attach->dmabuf->ops->cache_sgt_mapping) { - attach->sgt = sg_table; - attach->dir = direction; + for_each_sgtable_dma_sg(sg_table, sg, i) { + addr = sg_dma_address(sg); + len = sg_dma_len(sg); + if (!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(len)) { + pr_debug("%s: addr %llx or len %x is not page aligned!\n", + __func__, addr, len); + } + } } +#endif /* CONFIG_DMA_API_DEBUG */ + return sg_table; + +error_unmap: + attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, direction); + sg_table = ERR_PTR(ret); + +error_unpin: + if (dma_buf_pin_on_map(attach)) + attach->dmabuf->ops->unpin(attach); return sg_table; } -EXPORT_SYMBOL_GPL(dma_buf_map_attachment); +EXPORT_SYMBOL_NS_GPL(dma_buf_map_attachment, "DMA_BUF"); + +/** + * dma_buf_map_attachment_unlocked - Returns the scatterlist table of the attachment; + * mapped into _device_ address space. Is a wrapper for map_dma_buf() of the + * dma_buf_ops. + * @attach: [in] attachment whose scatterlist is to be returned + * @direction: [in] direction of DMA transfer + * + * Unlocked variant of dma_buf_map_attachment(). + */ +struct sg_table * +dma_buf_map_attachment_unlocked(struct dma_buf_attachment *attach, + enum dma_data_direction direction) +{ + struct sg_table *sg_table; + + might_sleep(); + + if (WARN_ON(!attach || !attach->dmabuf)) + return ERR_PTR(-EINVAL); + + dma_resv_lock(attach->dmabuf->resv, NULL); + sg_table = dma_buf_map_attachment(attach, direction); + dma_resv_unlock(attach->dmabuf->resv); + + return sg_table; +} +EXPORT_SYMBOL_NS_GPL(dma_buf_map_attachment_unlocked, "DMA_BUF"); /** * dma_buf_unmap_attachment - unmaps and decreases usecount of the buffer;might @@ -926,29 +1211,47 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach, if (WARN_ON(!attach || !attach->dmabuf || !sg_table)) return; - if (dma_buf_attachment_is_dynamic(attach)) - dma_resv_assert_held(attach->dmabuf->resv); + dma_resv_assert_held(attach->dmabuf->resv); - if (attach->sgt == sg_table) - return; + mangle_sg_table(sg_table); + attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, direction); - if (dma_buf_is_dynamic(attach->dmabuf)) - dma_resv_assert_held(attach->dmabuf->resv); + if (dma_buf_pin_on_map(attach)) + attach->dmabuf->ops->unpin(attach); +} +EXPORT_SYMBOL_NS_GPL(dma_buf_unmap_attachment, "DMA_BUF"); - attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, direction); +/** + * dma_buf_unmap_attachment_unlocked - unmaps and decreases usecount of the buffer;might + * deallocate the scatterlist associated. Is a wrapper for unmap_dma_buf() of + * dma_buf_ops. + * @attach: [in] attachment to unmap buffer from + * @sg_table: [in] scatterlist info of the buffer to unmap + * @direction: [in] direction of DMA transfer + * + * Unlocked variant of dma_buf_unmap_attachment(). + */ +void dma_buf_unmap_attachment_unlocked(struct dma_buf_attachment *attach, + struct sg_table *sg_table, + enum dma_data_direction direction) +{ + might_sleep(); - if (dma_buf_is_dynamic(attach->dmabuf) && - !IS_ENABLED(CONFIG_DMABUF_MOVE_NOTIFY)) - dma_buf_unpin(attach); + if (WARN_ON(!attach || !attach->dmabuf || !sg_table)) + return; + + dma_resv_lock(attach->dmabuf->resv, NULL); + dma_buf_unmap_attachment(attach, sg_table, direction); + dma_resv_unlock(attach->dmabuf->resv); } -EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment); +EXPORT_SYMBOL_NS_GPL(dma_buf_unmap_attachment_unlocked, "DMA_BUF"); /** * dma_buf_move_notify - notify attachments that DMA-buf is moving * * @dmabuf: [in] buffer which is moving * - * Informs all attachmenst that they need to destroy and recreated all their + * Informs all attachments that they need to destroy and recreate all their * mappings. */ void dma_buf_move_notify(struct dma_buf *dmabuf) @@ -961,16 +1264,16 @@ void dma_buf_move_notify(struct dma_buf *dmabuf) if (attach->importer_ops) attach->importer_ops->move_notify(attach); } -EXPORT_SYMBOL_GPL(dma_buf_move_notify); +EXPORT_SYMBOL_NS_GPL(dma_buf_move_notify, "DMA_BUF"); /** * DOC: cpu access * - * There are mutliple reasons for supporting CPU access to a dma buffer object: + * There are multiple reasons for supporting CPU access to a dma buffer object: * * - Fallback operations in the kernel, for example when a device is connected * over USB and the kernel needs to shuffle the data around first before - * sending it away. Cache coherency is handled by braketing any transactions + * sending it away. Cache coherency is handled by bracketing any transactions * with calls to dma_buf_begin_cpu_access() and dma_buf_end_cpu_access() * access. * @@ -978,16 +1281,18 @@ EXPORT_SYMBOL_GPL(dma_buf_move_notify); * vmap interface is introduced. Note that on very old 32-bit architectures * vmalloc space might be limited and result in vmap calls failing. * - * Interfaces:: - * void \*dma_buf_vmap(struct dma_buf \*dmabuf) - * void dma_buf_vunmap(struct dma_buf \*dmabuf, void \*vaddr) + * Interfaces: + * + * .. code-block:: c + * + * void *dma_buf_vmap(struct dma_buf *dmabuf, struct iosys_map *map) + * void dma_buf_vunmap(struct dma_buf *dmabuf, struct iosys_map *map) * * The vmap call can fail if there is no vmap support in the exporter, or if - * it runs out of vmalloc space. Fallback to kmap should be implemented. Note - * that the dma-buf layer keeps a reference count for all vmap access and - * calls down into the exporter's vmap function only when no vmapping exists, - * and only unmaps it once. Protection against concurrent vmap/vunmap calls is - * provided by taking the dma_buf->lock mutex. + * it runs out of vmalloc space. Note that the dma-buf layer keeps a reference + * count for all vmap access and calls down into the exporter's vmap function + * only when no vmapping exists, and only unmaps it once. Protection against + * concurrent vmap/vunmap calls is provided by taking the &dma_buf.lock mutex. * * - For full compatibility on the importer side with existing userspace * interfaces, which might already support mmap'ing buffers. This is needed in @@ -997,7 +1302,7 @@ EXPORT_SYMBOL_GPL(dma_buf_move_notify); * replace ION buffers mmap support was needed. * * There is no special interfaces, userspace simply calls mmap on the dma-buf - * fd. But like for CPU access there's a need to braket the actual access, + * fd. But like for CPU access there's a need to bracket the actual access, * which is handled by the ioctl (DMA_BUF_IOCTL_SYNC). Note that * DMA_BUF_IOCTL_SYNC can fail with -EAGAIN or -EINTR, in which case it must * be restarted. @@ -1038,12 +1343,14 @@ EXPORT_SYMBOL_GPL(dma_buf_move_notify); * enough, since adding interfaces to intercept pagefaults and allow pte * shootdowns would increase the complexity quite a bit. * - * Interface:: - * int dma_buf_mmap(struct dma_buf \*, struct vm_area_struct \*, - * unsigned long); + * Interface: + * + * .. code-block:: c + * + * int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *, unsigned long); * * If the importing subsystem simply provides a special-purpose mmap call to - * set up a mapping in userspace, calling do_mmap with dma_buf->file will + * set up a mapping in userspace, calling do_mmap with &dma_buf.file will * equally achieve that for a dma-buf object. */ @@ -1056,8 +1363,8 @@ static int __dma_buf_begin_cpu_access(struct dma_buf *dmabuf, long ret; /* Wait on any implicit rendering fences */ - ret = dma_resv_wait_timeout_rcu(resv, write, true, - MAX_SCHEDULE_TIMEOUT); + ret = dma_resv_wait_timeout(resv, dma_resv_usage_rw(write), + true, MAX_SCHEDULE_TIMEOUT); if (ret < 0) return ret; @@ -1070,12 +1377,17 @@ static int __dma_buf_begin_cpu_access(struct dma_buf *dmabuf, * preparations. Coherency is only guaranteed in the specified range for the * specified access direction. * @dmabuf: [in] buffer to prepare cpu access for. - * @direction: [in] length of range for cpu access. + * @direction: [in] direction of access. * * After the cpu access is complete the caller should call - * dma_buf_end_cpu_access(). Only when cpu access is braketed by both calls is + * dma_buf_end_cpu_access(). Only when cpu access is bracketed by both calls is * it guaranteed to be coherent with other DMA access. * + * This function will also wait for any DMA transactions tracked through + * implicit synchronization in &dma_buf.resv. For DMA transactions with explicit + * synchronization this function will only ensure cache coherency, callers must + * ensure synchronization with such DMA transactions on their own. + * * Can return negative error values, returns 0 on success. */ int dma_buf_begin_cpu_access(struct dma_buf *dmabuf, @@ -1086,6 +1398,8 @@ int dma_buf_begin_cpu_access(struct dma_buf *dmabuf, if (WARN_ON(!dmabuf)) return -EINVAL; + might_lock(&dmabuf->resv->lock.base); + if (dmabuf->ops->begin_cpu_access) ret = dmabuf->ops->begin_cpu_access(dmabuf, direction); @@ -1098,7 +1412,7 @@ int dma_buf_begin_cpu_access(struct dma_buf *dmabuf, return ret; } -EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access); +EXPORT_SYMBOL_NS_GPL(dma_buf_begin_cpu_access, "DMA_BUF"); /** * dma_buf_end_cpu_access - Must be called after accessing a dma_buf from the @@ -1106,7 +1420,7 @@ EXPORT_SYMBOL_GPL(dma_buf_begin_cpu_access); * actions. Coherency is only guaranteed in the specified range for the * specified access direction. * @dmabuf: [in] buffer to complete cpu access for. - * @direction: [in] length of range for cpu access. + * @direction: [in] direction of access. * * This terminates CPU access started with dma_buf_begin_cpu_access(). * @@ -1119,12 +1433,14 @@ int dma_buf_end_cpu_access(struct dma_buf *dmabuf, WARN_ON(!dmabuf); + might_lock(&dmabuf->resv->lock.base); + if (dmabuf->ops->end_cpu_access) ret = dmabuf->ops->end_cpu_access(dmabuf, direction); return ret; } -EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access); +EXPORT_SYMBOL_NS_GPL(dma_buf_end_cpu_access, "DMA_BUF"); /** @@ -1144,9 +1460,6 @@ EXPORT_SYMBOL_GPL(dma_buf_end_cpu_access); int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, unsigned long pgoff) { - struct file *oldfile; - int ret; - if (WARN_ON(!dmabuf || !vma)) return -EINVAL; @@ -1164,160 +1477,169 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma, return -EINVAL; /* readjust the vma */ - get_file(dmabuf->file); - oldfile = vma->vm_file; - vma->vm_file = dmabuf->file; + vma_set_file(vma, dmabuf->file); vma->vm_pgoff = pgoff; - ret = dmabuf->ops->mmap(dmabuf, vma); - if (ret) { - /* restore old parameters on failure */ - vma->vm_file = oldfile; - fput(dmabuf->file); - } else { - if (oldfile) - fput(oldfile); - } - return ret; - + return dmabuf->ops->mmap(dmabuf, vma); } -EXPORT_SYMBOL_GPL(dma_buf_mmap); +EXPORT_SYMBOL_NS_GPL(dma_buf_mmap, "DMA_BUF"); /** * dma_buf_vmap - Create virtual mapping for the buffer object into kernel * address space. Same restrictions as for vmap and friends apply. * @dmabuf: [in] buffer to vmap + * @map: [out] returns the vmap pointer * * This call may fail due to lack of virtual mapping address space. * These calls are optional in drivers. The intended use for them * is for mapping objects linear in kernel space for high use objects. - * Please attempt to use kmap/kunmap before thinking about these interfaces. * - * Returns NULL on error. + * To ensure coherency users must call dma_buf_begin_cpu_access() and + * dma_buf_end_cpu_access() around any cpu access performed through this + * mapping. + * + * Returns 0 on success, or a negative errno code otherwise. */ -void *dma_buf_vmap(struct dma_buf *dmabuf) +int dma_buf_vmap(struct dma_buf *dmabuf, struct iosys_map *map) { - void *ptr; + struct iosys_map ptr; + int ret; + + iosys_map_clear(map); if (WARN_ON(!dmabuf)) - return NULL; + return -EINVAL; + + dma_resv_assert_held(dmabuf->resv); if (!dmabuf->ops->vmap) - return NULL; + return -EINVAL; - mutex_lock(&dmabuf->lock); if (dmabuf->vmapping_counter) { dmabuf->vmapping_counter++; - BUG_ON(!dmabuf->vmap_ptr); - ptr = dmabuf->vmap_ptr; - goto out_unlock; + BUG_ON(iosys_map_is_null(&dmabuf->vmap_ptr)); + *map = dmabuf->vmap_ptr; + return 0; } - BUG_ON(dmabuf->vmap_ptr); + BUG_ON(iosys_map_is_set(&dmabuf->vmap_ptr)); - ptr = dmabuf->ops->vmap(dmabuf); - if (WARN_ON_ONCE(IS_ERR(ptr))) - ptr = NULL; - if (!ptr) - goto out_unlock; + ret = dmabuf->ops->vmap(dmabuf, &ptr); + if (WARN_ON_ONCE(ret)) + return ret; dmabuf->vmap_ptr = ptr; dmabuf->vmapping_counter = 1; -out_unlock: - mutex_unlock(&dmabuf->lock); - return ptr; + *map = dmabuf->vmap_ptr; + + return 0; +} +EXPORT_SYMBOL_NS_GPL(dma_buf_vmap, "DMA_BUF"); + +/** + * dma_buf_vmap_unlocked - Create virtual mapping for the buffer object into kernel + * address space. Same restrictions as for vmap and friends apply. + * @dmabuf: [in] buffer to vmap + * @map: [out] returns the vmap pointer + * + * Unlocked version of dma_buf_vmap() + * + * Returns 0 on success, or a negative errno code otherwise. + */ +int dma_buf_vmap_unlocked(struct dma_buf *dmabuf, struct iosys_map *map) +{ + int ret; + + iosys_map_clear(map); + + if (WARN_ON(!dmabuf)) + return -EINVAL; + + dma_resv_lock(dmabuf->resv, NULL); + ret = dma_buf_vmap(dmabuf, map); + dma_resv_unlock(dmabuf->resv); + + return ret; } -EXPORT_SYMBOL_GPL(dma_buf_vmap); +EXPORT_SYMBOL_NS_GPL(dma_buf_vmap_unlocked, "DMA_BUF"); /** * dma_buf_vunmap - Unmap a vmap obtained by dma_buf_vmap. * @dmabuf: [in] buffer to vunmap - * @vaddr: [in] vmap to vunmap + * @map: [in] vmap pointer to vunmap */ -void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr) +void dma_buf_vunmap(struct dma_buf *dmabuf, struct iosys_map *map) { if (WARN_ON(!dmabuf)) return; - BUG_ON(!dmabuf->vmap_ptr); + dma_resv_assert_held(dmabuf->resv); + + BUG_ON(iosys_map_is_null(&dmabuf->vmap_ptr)); BUG_ON(dmabuf->vmapping_counter == 0); - BUG_ON(dmabuf->vmap_ptr != vaddr); + BUG_ON(!iosys_map_is_equal(&dmabuf->vmap_ptr, map)); - mutex_lock(&dmabuf->lock); if (--dmabuf->vmapping_counter == 0) { if (dmabuf->ops->vunmap) - dmabuf->ops->vunmap(dmabuf, vaddr); - dmabuf->vmap_ptr = NULL; + dmabuf->ops->vunmap(dmabuf, map); + iosys_map_clear(&dmabuf->vmap_ptr); } - mutex_unlock(&dmabuf->lock); } -EXPORT_SYMBOL_GPL(dma_buf_vunmap); +EXPORT_SYMBOL_NS_GPL(dma_buf_vunmap, "DMA_BUF"); + +/** + * dma_buf_vunmap_unlocked - Unmap a vmap obtained by dma_buf_vmap. + * @dmabuf: [in] buffer to vunmap + * @map: [in] vmap pointer to vunmap + */ +void dma_buf_vunmap_unlocked(struct dma_buf *dmabuf, struct iosys_map *map) +{ + if (WARN_ON(!dmabuf)) + return; + + dma_resv_lock(dmabuf->resv, NULL); + dma_buf_vunmap(dmabuf, map); + dma_resv_unlock(dmabuf->resv); +} +EXPORT_SYMBOL_NS_GPL(dma_buf_vunmap_unlocked, "DMA_BUF"); #ifdef CONFIG_DEBUG_FS static int dma_buf_debug_show(struct seq_file *s, void *unused) { - int ret; struct dma_buf *buf_obj; struct dma_buf_attachment *attach_obj; - struct dma_resv *robj; - struct dma_resv_list *fobj; - struct dma_fence *fence; - unsigned seq; - int count = 0, attach_count, shared_count, i; + int count = 0, attach_count; size_t size = 0; + int ret; - ret = mutex_lock_interruptible(&db_list.lock); + ret = mutex_lock_interruptible(&dmabuf_list_mutex); if (ret) return ret; seq_puts(s, "\nDma-buf Objects:\n"); - seq_printf(s, "%-8s\t%-8s\t%-8s\t%-8s\texp_name\t%-8s\n", + seq_printf(s, "%-8s\t%-8s\t%-8s\t%-8s\texp_name\t%-8s\tname\n", "size", "flags", "mode", "count", "ino"); - list_for_each_entry(buf_obj, &db_list.head, list_node) { + list_for_each_entry(buf_obj, &dmabuf_list, list_node) { ret = dma_resv_lock_interruptible(buf_obj->resv, NULL); if (ret) goto error_unlock; + + spin_lock(&buf_obj->name_lock); seq_printf(s, "%08zu\t%08x\t%08x\t%08ld\t%s\t%08lu\t%s\n", buf_obj->size, buf_obj->file->f_flags, buf_obj->file->f_mode, file_count(buf_obj->file), buf_obj->exp_name, file_inode(buf_obj->file)->i_ino, - buf_obj->name ?: ""); - - robj = buf_obj->resv; - while (true) { - seq = read_seqcount_begin(&robj->seq); - rcu_read_lock(); - fobj = rcu_dereference(robj->fence); - shared_count = fobj ? fobj->shared_count : 0; - fence = rcu_dereference(robj->fence_excl); - if (!read_seqcount_retry(&robj->seq, seq)) - break; - rcu_read_unlock(); - } + buf_obj->name ?: "<none>"); + spin_unlock(&buf_obj->name_lock); - if (fence) - seq_printf(s, "\tExclusive fence: %s %s %ssignalled\n", - fence->ops->get_driver_name(fence), - fence->ops->get_timeline_name(fence), - dma_fence_is_signaled(fence) ? "" : "un"); - for (i = 0; i < shared_count; i++) { - fence = rcu_dereference(fobj->shared[i]); - if (!dma_fence_get_rcu(fence)) - continue; - seq_printf(s, "\tShared fence: %s %s %ssignalled\n", - fence->ops->get_driver_name(fence), - fence->ops->get_timeline_name(fence), - dma_fence_is_signaled(fence) ? "" : "un"); - dma_fence_put(fence); - } - rcu_read_unlock(); + dma_resv_describe(buf_obj->resv, s); seq_puts(s, "\tAttached Devices:\n"); attach_count = 0; @@ -1337,11 +1659,11 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused) seq_printf(s, "\nTotal %d objects, %zu bytes\n", count, size); - mutex_unlock(&db_list.lock); + mutex_unlock(&dmabuf_list_mutex); return 0; error_unlock: - mutex_unlock(&db_list.lock); + mutex_unlock(&dmabuf_list_mutex); return ret; } @@ -1360,7 +1682,7 @@ static int dma_buf_init_debugfs(void) dma_buf_debugfs_dir = d; - d = debugfs_create_file("bufinfo", S_IRUGO, dma_buf_debugfs_dir, + d = debugfs_create_file("bufinfo", 0444, dma_buf_debugfs_dir, NULL, &dma_buf_debug_fops); if (IS_ERR(d)) { pr_debug("dma_buf: debugfs: failed to create node bufinfo\n"); @@ -1388,12 +1710,16 @@ static inline void dma_buf_uninit_debugfs(void) static int __init dma_buf_init(void) { + int ret; + + ret = dma_buf_init_sysfs_statistics(); + if (ret) + return ret; + dma_buf_mnt = kern_mount(&dma_buf_fs_type); if (IS_ERR(dma_buf_mnt)) return PTR_ERR(dma_buf_mnt); - mutex_init(&db_list.lock); - INIT_LIST_HEAD(&db_list.head); dma_buf_init_debugfs(); return 0; } @@ -1403,5 +1729,6 @@ static void __exit dma_buf_deinit(void) { dma_buf_uninit_debugfs(); kern_unmount(dma_buf_mnt); + dma_buf_uninit_sysfs_statistics(); } __exitcall(dma_buf_deinit); |