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path: root/drivers/block/xen-blkback/xenbus.c
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Diffstat (limited to 'drivers/block/xen-blkback/xenbus.c')
-rw-r--r--drivers/block/xen-blkback/xenbus.c310
1 files changed, 186 insertions, 124 deletions
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index a4bc74e72c39..0621878940ae 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -1,24 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
/* Xenbus code for blkif backend
Copyright (C) 2005 Rusty Russell <rusty@rustcorp.com.au>
Copyright (C) 2005 XenSource Ltd
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
- (at your option) any later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
*/
#define pr_fmt(fmt) "xen-blkback: " fmt
-#include <stdarg.h>
#include <linux/module.h>
#include <linux/kthread.h>
+#include <linux/pagemap.h>
#include <xen/events.h>
#include <xen/grant_table.h>
#include "common.h"
@@ -89,7 +81,7 @@ static void xen_update_blkif_status(struct xen_blkif *blkif)
int i;
/* Not ready to connect? */
- if (!blkif->rings || !blkif->rings[0].irq || !blkif->vbd.bdev)
+ if (!blkif->rings || !blkif->rings[0].irq || !blkif->vbd.bdev_file)
return;
/* Already connected? */
@@ -107,12 +99,12 @@ static void xen_update_blkif_status(struct xen_blkif *blkif)
return;
}
- err = filemap_write_and_wait(blkif->vbd.bdev->bd_inode->i_mapping);
+ err = sync_blockdev(file_bdev(blkif->vbd.bdev_file));
if (err) {
xenbus_dev_error(blkif->be->dev, err, "block flush");
return;
}
- invalidate_inode_pages2(blkif->vbd.bdev->bd_inode->i_mapping);
+ invalidate_inode_pages2(blkif->vbd.bdev_file->f_mapping);
for (i = 0; i < blkif->nr_rings; i++) {
ring = &blkif->rings[i];
@@ -152,8 +144,7 @@ static int xen_blkif_alloc_rings(struct xen_blkif *blkif)
INIT_LIST_HEAD(&ring->pending_free);
INIT_LIST_HEAD(&ring->persistent_purge_list);
INIT_WORK(&ring->persistent_purge_work, xen_blkbk_unmap_purged_grants);
- spin_lock_init(&ring->free_pages_lock);
- INIT_LIST_HEAD(&ring->free_pages);
+ gnttab_page_cache_init(&ring->free_pages);
spin_lock_init(&ring->pending_free_lock);
init_waitqueue_head(&ring->pending_free_wq);
@@ -166,6 +157,11 @@ static int xen_blkif_alloc_rings(struct xen_blkif *blkif)
return 0;
}
+/* Enable the persistent grants feature. */
+static bool feature_persistent = true;
+module_param(feature_persistent, bool, 0644);
+MODULE_PARM_DESC(feature_persistent, "Enables the persistent grants feature");
+
static struct xen_blkif *xen_blkif_alloc(domid_t domid)
{
struct xen_blkif *blkif;
@@ -179,6 +175,15 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid)
blkif->domid = domid;
atomic_set(&blkif->refcnt, 1);
init_completion(&blkif->drain_complete);
+
+ /*
+ * Because freeing back to the cache may be deferred, it is not
+ * safe to unload the module (and hence destroy the cache) until
+ * this has completed. To prevent premature unloading, take an
+ * extra module reference here and release only when the object
+ * has been freed back to the cache.
+ */
+ __module_get(THIS_MODULE);
INIT_WORK(&blkif->free_work, xen_blkif_deferred_free);
return blkif;
@@ -189,6 +194,9 @@ static int xen_blkif_map(struct xen_blkif_ring *ring, grant_ref_t *gref,
{
int err;
struct xen_blkif *blkif = ring->blkif;
+ const struct blkif_common_sring *sring_common;
+ RING_IDX rsp_prod, req_prod;
+ unsigned int size;
/* Already connected through? */
if (ring->irq)
@@ -199,46 +207,61 @@ static int xen_blkif_map(struct xen_blkif_ring *ring, grant_ref_t *gref,
if (err < 0)
return err;
+ sring_common = (struct blkif_common_sring *)ring->blk_ring;
+ rsp_prod = READ_ONCE(sring_common->rsp_prod);
+ req_prod = READ_ONCE(sring_common->req_prod);
+
switch (blkif->blk_protocol) {
case BLKIF_PROTOCOL_NATIVE:
{
- struct blkif_sring *sring;
- sring = (struct blkif_sring *)ring->blk_ring;
- BACK_RING_INIT(&ring->blk_rings.native, sring,
- XEN_PAGE_SIZE * nr_grefs);
+ struct blkif_sring *sring_native =
+ (struct blkif_sring *)ring->blk_ring;
+
+ BACK_RING_ATTACH(&ring->blk_rings.native, sring_native,
+ rsp_prod, XEN_PAGE_SIZE * nr_grefs);
+ size = __RING_SIZE(sring_native, XEN_PAGE_SIZE * nr_grefs);
break;
}
case BLKIF_PROTOCOL_X86_32:
{
- struct blkif_x86_32_sring *sring_x86_32;
- sring_x86_32 = (struct blkif_x86_32_sring *)ring->blk_ring;
- BACK_RING_INIT(&ring->blk_rings.x86_32, sring_x86_32,
- XEN_PAGE_SIZE * nr_grefs);
+ struct blkif_x86_32_sring *sring_x86_32 =
+ (struct blkif_x86_32_sring *)ring->blk_ring;
+
+ BACK_RING_ATTACH(&ring->blk_rings.x86_32, sring_x86_32,
+ rsp_prod, XEN_PAGE_SIZE * nr_grefs);
+ size = __RING_SIZE(sring_x86_32, XEN_PAGE_SIZE * nr_grefs);
break;
}
case BLKIF_PROTOCOL_X86_64:
{
- struct blkif_x86_64_sring *sring_x86_64;
- sring_x86_64 = (struct blkif_x86_64_sring *)ring->blk_ring;
- BACK_RING_INIT(&ring->blk_rings.x86_64, sring_x86_64,
- XEN_PAGE_SIZE * nr_grefs);
+ struct blkif_x86_64_sring *sring_x86_64 =
+ (struct blkif_x86_64_sring *)ring->blk_ring;
+
+ BACK_RING_ATTACH(&ring->blk_rings.x86_64, sring_x86_64,
+ rsp_prod, XEN_PAGE_SIZE * nr_grefs);
+ size = __RING_SIZE(sring_x86_64, XEN_PAGE_SIZE * nr_grefs);
break;
}
default:
BUG();
}
- err = bind_interdomain_evtchn_to_irqhandler(blkif->domid, evtchn,
- xen_blkif_be_int, 0,
- "blkif-backend", ring);
- if (err < 0) {
- xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring);
- ring->blk_rings.common.sring = NULL;
- return err;
- }
+ err = -EIO;
+ if (req_prod - rsp_prod > size)
+ goto fail;
+
+ err = bind_interdomain_evtchn_to_irqhandler_lateeoi(blkif->be->dev,
+ evtchn, xen_blkif_be_int, 0, "blkif-backend", ring);
+ if (err < 0)
+ goto fail;
ring->irq = err;
return 0;
+
+fail:
+ xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring);
+ ring->blk_rings.common.sring = NULL;
+ return err;
}
static int xen_blkif_disconnect(struct xen_blkif *blkif)
@@ -256,6 +279,7 @@ static int xen_blkif_disconnect(struct xen_blkif *blkif)
if (ring->xenblkd) {
kthread_stop(ring->xenblkd);
+ ring->xenblkd = NULL;
wake_up(&ring->shutdown_wq);
}
@@ -298,8 +322,7 @@ static int xen_blkif_disconnect(struct xen_blkif *blkif)
BUG_ON(atomic_read(&ring->persistent_gnt_in_use) != 0);
BUG_ON(!list_empty(&ring->persistent_purge_list));
BUG_ON(!RB_EMPTY_ROOT(&ring->persistent_gnts));
- BUG_ON(!list_empty(&ring->free_pages));
- BUG_ON(ring->free_pages_num != 0);
+ BUG_ON(ring->free_pages.num_pages != 0);
BUG_ON(ring->persistent_gnt_c != 0);
WARN_ON(i != (XEN_BLKIF_REQS_PER_PAGE * blkif->nr_ring_pages));
ring->active = false;
@@ -328,6 +351,7 @@ static void xen_blkif_free(struct xen_blkif *blkif)
/* Make sure everything is drained before shutting down */
kmem_cache_free(xen_blkif_cachep, blkif);
+ module_put(THIS_MODULE);
}
int __init xen_blkif_interface_init(void)
@@ -341,6 +365,12 @@ int __init xen_blkif_interface_init(void)
return 0;
}
+void xen_blkif_interface_fini(void)
+{
+ kmem_cache_destroy(xen_blkif_cachep);
+ xen_blkif_cachep = NULL;
+}
+
/*
* sysfs interface for VBD I/O requests
*/
@@ -440,12 +470,11 @@ static void xenvbd_sysfs_delif(struct xenbus_device *dev)
device_remove_file(&dev->dev, &dev_attr_physical_device);
}
-
static void xen_vbd_free(struct xen_vbd *vbd)
{
- if (vbd->bdev)
- blkdev_put(vbd->bdev, vbd->readonly ? FMODE_READ : FMODE_WRITE);
- vbd->bdev = NULL;
+ if (vbd->bdev_file)
+ fput(vbd->bdev_file);
+ vbd->bdev_file = NULL;
}
static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
@@ -453,8 +482,7 @@ static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
int cdrom)
{
struct xen_vbd *vbd;
- struct block_device *bdev;
- struct request_queue *q;
+ struct file *bdev_file;
vbd = &blkif->vbd;
vbd->handle = handle;
@@ -463,17 +491,17 @@ static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
vbd->pdevice = MKDEV(major, minor);
- bdev = blkdev_get_by_dev(vbd->pdevice, vbd->readonly ?
- FMODE_READ : FMODE_WRITE, NULL);
+ bdev_file = bdev_file_open_by_dev(vbd->pdevice, vbd->readonly ?
+ BLK_OPEN_READ : BLK_OPEN_WRITE, NULL, NULL);
- if (IS_ERR(bdev)) {
+ if (IS_ERR(bdev_file)) {
pr_warn("xen_vbd_create: device %08x could not be opened\n",
vbd->pdevice);
return -ENOENT;
}
- vbd->bdev = bdev;
- if (vbd->bdev->bd_disk == NULL) {
+ vbd->bdev_file = bdev_file;
+ if (file_bdev(vbd->bdev_file)->bd_disk == NULL) {
pr_warn("xen_vbd_create: device %08x doesn't exist\n",
vbd->pdevice);
xen_vbd_free(vbd);
@@ -481,23 +509,22 @@ static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
}
vbd->size = vbd_sz(vbd);
- if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom)
+ if (cdrom || disk_to_cdi(file_bdev(vbd->bdev_file)->bd_disk))
vbd->type |= VDISK_CDROM;
- if (vbd->bdev->bd_disk->flags & GENHD_FL_REMOVABLE)
+ if (file_bdev(vbd->bdev_file)->bd_disk->flags & GENHD_FL_REMOVABLE)
vbd->type |= VDISK_REMOVABLE;
- q = bdev_get_queue(bdev);
- if (q && test_bit(QUEUE_FLAG_WC, &q->queue_flags))
+ if (bdev_write_cache(file_bdev(bdev_file)))
vbd->flush_support = true;
-
- if (q && blk_queue_secure_erase(q))
+ if (bdev_max_secure_erase_sectors(file_bdev(bdev_file)))
vbd->discard_secure = true;
pr_debug("Successful creation of handle=%04x (dom=%u)\n",
handle, blkif->domid);
return 0;
}
-static int xen_blkbk_remove(struct xenbus_device *dev)
+
+static void xen_blkbk_remove(struct xenbus_device *dev)
{
struct backend_info *be = dev_get_drvdata(&dev->dev);
@@ -520,8 +547,6 @@ static int xen_blkbk_remove(struct xenbus_device *dev)
/* Put the reference we set in xen_blkif_alloc(). */
xen_blkif_put(be->blkif);
}
-
- return 0;
}
int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
@@ -544,23 +569,22 @@ static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info
struct xen_blkif *blkif = be->blkif;
int err;
int state = 0;
- struct block_device *bdev = be->blkif->vbd.bdev;
- struct request_queue *q = bdev_get_queue(bdev);
+ struct block_device *bdev = file_bdev(be->blkif->vbd.bdev_file);
if (!xenbus_read_unsigned(dev->nodename, "discard-enable", 1))
return;
- if (blk_queue_discard(q)) {
+ if (bdev_max_discard_sectors(bdev)) {
err = xenbus_printf(xbt, dev->nodename,
"discard-granularity", "%u",
- q->limits.discard_granularity);
+ bdev_discard_granularity(bdev));
if (err) {
dev_warn(&dev->dev, "writing discard-granularity (%d)", err);
return;
}
err = xenbus_printf(xbt, dev->nodename,
"discard-alignment", "%u",
- q->limits.discard_alignment);
+ bdev_discard_alignment(bdev));
if (err) {
dev_warn(&dev->dev, "writing discard-alignment (%d)", err);
return;
@@ -580,6 +604,7 @@ static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info
if (err)
dev_warn(&dev->dev, "writing feature-discard (%d)", err);
}
+
int xen_blkbk_barrier(struct xenbus_transaction xbt,
struct backend_info *be, int state)
{
@@ -642,7 +667,8 @@ static int xen_blkbk_probe(struct xenbus_device *dev,
/* setup back pointer */
be->blkif->be = be;
- err = xenbus_watch_pathfmt(dev, &be->backend_watch, backend_changed,
+ err = xenbus_watch_pathfmt(dev, &be->backend_watch, NULL,
+ backend_changed,
"%s/%s", dev->nodename, "physical-device");
if (err)
goto fail;
@@ -664,7 +690,6 @@ fail:
return err;
}
-
/*
* Callback received when the hotplug scripts have placed the physical-device
* node. Read it and the mode node, and create a vbd. If the frontend is
@@ -756,7 +781,6 @@ static void backend_changed(struct xenbus_watch *watch,
}
}
-
/*
* Callback received when the frontend's state changes.
*/
@@ -817,7 +841,7 @@ static void frontend_changed(struct xenbus_device *dev,
xenbus_switch_state(dev, XenbusStateClosed);
if (xenbus_dev_is_online(dev))
break;
- /* fall through */
+ fallthrough;
/* if not online */
case XenbusStateUnknown:
/* implies xen_blkif_disconnect() via xen_blkbk_remove() */
@@ -831,9 +855,27 @@ static void frontend_changed(struct xenbus_device *dev,
}
}
+/* Once a memory pressure is detected, squeeze free page pools for a while. */
+static unsigned int buffer_squeeze_duration_ms = 10;
+module_param_named(buffer_squeeze_duration_ms,
+ buffer_squeeze_duration_ms, int, 0644);
+MODULE_PARM_DESC(buffer_squeeze_duration_ms,
+"Duration in ms to squeeze pages buffer when a memory pressure is detected");
-/* ** Connection ** */
+/*
+ * Callback received when the memory pressure is detected.
+ */
+static void reclaim_memory(struct xenbus_device *dev)
+{
+ struct backend_info *be = dev_get_drvdata(&dev->dev);
+
+ if (!be)
+ return;
+ be->blkif->buffer_squeeze_end = jiffies +
+ msecs_to_jiffies(buffer_squeeze_duration_ms);
+}
+/* ** Connection ** */
/*
* Write the physical details regarding the block device to the store, and
@@ -862,7 +904,8 @@ again:
xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support);
- err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", 1);
+ err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u",
+ be->blkif->vbd.feature_gnt_persistent_parm);
if (err) {
xenbus_dev_fatal(dev, err, "writing %s/feature-persistent",
dev->nodename);
@@ -887,15 +930,16 @@ again:
goto abort;
}
err = xenbus_printf(xbt, dev->nodename, "sector-size", "%lu",
- (unsigned long)
- bdev_logical_block_size(be->blkif->vbd.bdev));
+ (unsigned long)bdev_logical_block_size(
+ file_bdev(be->blkif->vbd.bdev_file)));
if (err) {
xenbus_dev_fatal(dev, err, "writing %s/sector-size",
dev->nodename);
goto abort;
}
err = xenbus_printf(xbt, dev->nodename, "physical-sector-size", "%u",
- bdev_physical_block_size(be->blkif->vbd.bdev));
+ bdev_physical_block_size(
+ file_bdev(be->blkif->vbd.bdev_file)));
if (err)
xenbus_dev_error(dev, err, "writing %s/physical-sector-size",
dev->nodename);
@@ -926,7 +970,7 @@ static int read_per_ring_refs(struct xen_blkif_ring *ring, const char *dir)
int err, i, j;
struct xen_blkif *blkif = ring->blkif;
struct xenbus_device *dev = blkif->be->dev;
- unsigned int ring_page_order, nr_grefs, evtchn;
+ unsigned int nr_grefs, evtchn;
err = xenbus_scanf(XBT_NIL, dir, "event-channel", "%u",
&evtchn);
@@ -936,44 +980,35 @@ static int read_per_ring_refs(struct xen_blkif_ring *ring, const char *dir)
return err;
}
- err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-page-order", "%u",
- &ring_page_order);
- if (err != 1) {
- err = xenbus_scanf(XBT_NIL, dir, "ring-ref", "%u", &ring_ref[0]);
- if (err != 1) {
- err = -EINVAL;
- xenbus_dev_fatal(dev, err, "reading %s/ring-ref", dir);
- return err;
- }
- nr_grefs = 1;
- } else {
- unsigned int i;
+ nr_grefs = blkif->nr_ring_pages;
- if (ring_page_order > xen_blkif_max_ring_order) {
- err = -EINVAL;
- xenbus_dev_fatal(dev, err, "%s/request %d ring page order exceed max:%d",
- dir, ring_page_order,
- xen_blkif_max_ring_order);
- return err;
- }
+ if (unlikely(!nr_grefs)) {
+ WARN_ON(true);
+ return -EINVAL;
+ }
- nr_grefs = 1 << ring_page_order;
- for (i = 0; i < nr_grefs; i++) {
- char ring_ref_name[RINGREF_NAME_LEN];
+ for (i = 0; i < nr_grefs; i++) {
+ char ring_ref_name[RINGREF_NAME_LEN];
+ if (blkif->multi_ref)
snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i);
- err = xenbus_scanf(XBT_NIL, dir, ring_ref_name,
- "%u", &ring_ref[i]);
- if (err != 1) {
- err = -EINVAL;
- xenbus_dev_fatal(dev, err, "reading %s/%s",
- dir, ring_ref_name);
- return err;
- }
+ else {
+ WARN_ON(i != 0);
+ snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref");
+ }
+
+ err = xenbus_scanf(XBT_NIL, dir, ring_ref_name,
+ "%u", &ring_ref[i]);
+
+ if (err != 1) {
+ err = -EINVAL;
+ xenbus_dev_fatal(dev, err, "reading %s/%s",
+ dir, ring_ref_name);
+ return err;
}
}
- blkif->nr_ring_pages = nr_grefs;
+ err = -ENOMEM;
for (i = 0; i < nr_grefs * XEN_BLKIF_REQS_PER_PAGE; i++) {
req = kzalloc(sizeof(*req), GFP_KERNEL);
if (!req)
@@ -996,7 +1031,7 @@ static int read_per_ring_refs(struct xen_blkif_ring *ring, const char *dir)
err = xen_blkif_map(ring, ring_ref, nr_grefs, evtchn);
if (err) {
xenbus_dev_fatal(dev, err, "mapping ring-ref port %u", evtchn);
- return err;
+ goto fail;
}
return 0;
@@ -1016,42 +1051,45 @@ fail:
}
kfree(req);
}
- return -ENOMEM;
-
+ return err;
}
static int connect_ring(struct backend_info *be)
{
struct xenbus_device *dev = be->dev;
- unsigned int pers_grants;
+ struct xen_blkif *blkif = be->blkif;
char protocol[64] = "";
int err, i;
char *xspath;
size_t xspathsize;
const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */
unsigned int requested_num_queues = 0;
+ unsigned int ring_page_order;
pr_debug("%s %s\n", __func__, dev->otherend);
- be->blkif->blk_protocol = BLKIF_PROTOCOL_DEFAULT;
+ blkif->blk_protocol = BLKIF_PROTOCOL_DEFAULT;
err = xenbus_scanf(XBT_NIL, dev->otherend, "protocol",
"%63s", protocol);
if (err <= 0)
strcpy(protocol, "unspecified, assuming default");
else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE))
- be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
+ blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32))
- be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_32;
+ blkif->blk_protocol = BLKIF_PROTOCOL_X86_32;
else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64))
- be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_64;
+ blkif->blk_protocol = BLKIF_PROTOCOL_X86_64;
else {
xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol);
return -ENOSYS;
}
- pers_grants = xenbus_read_unsigned(dev->otherend, "feature-persistent",
- 0);
- be->blkif->vbd.feature_gnt_persistent = pers_grants;
- be->blkif->vbd.overflow_max_grants = 0;
+
+ blkif->vbd.feature_gnt_persistent_parm = feature_persistent;
+ blkif->vbd.feature_gnt_persistent =
+ blkif->vbd.feature_gnt_persistent_parm &&
+ xenbus_read_unsigned(dev->otherend, "feature-persistent", 0);
+
+ blkif->vbd.overflow_max_grants = 0;
/*
* Read the number of hardware queues from frontend.
@@ -1067,16 +1105,33 @@ static int connect_ring(struct backend_info *be)
requested_num_queues, xenblk_max_queues);
return -ENOSYS;
}
- be->blkif->nr_rings = requested_num_queues;
- if (xen_blkif_alloc_rings(be->blkif))
+ blkif->nr_rings = requested_num_queues;
+ if (xen_blkif_alloc_rings(blkif))
return -ENOMEM;
pr_info("%s: using %d queues, protocol %d (%s) %s\n", dev->nodename,
- be->blkif->nr_rings, be->blkif->blk_protocol, protocol,
- pers_grants ? "persistent grants" : "");
+ blkif->nr_rings, blkif->blk_protocol, protocol,
+ blkif->vbd.feature_gnt_persistent ? "persistent grants" : "");
- if (be->blkif->nr_rings == 1)
- return read_per_ring_refs(&be->blkif->rings[0], dev->otherend);
+ err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-page-order", "%u",
+ &ring_page_order);
+ if (err != 1) {
+ blkif->nr_ring_pages = 1;
+ blkif->multi_ref = false;
+ } else if (ring_page_order <= xen_blkif_max_ring_order) {
+ blkif->nr_ring_pages = 1 << ring_page_order;
+ blkif->multi_ref = true;
+ } else {
+ err = -EINVAL;
+ xenbus_dev_fatal(dev, err,
+ "requested ring page order %d exceed max:%d",
+ ring_page_order,
+ xen_blkif_max_ring_order);
+ return err;
+ }
+
+ if (blkif->nr_rings == 1)
+ return read_per_ring_refs(&blkif->rings[0], dev->otherend);
else {
xspathsize = strlen(dev->otherend) + xenstore_path_ext_size;
xspath = kmalloc(xspathsize, GFP_KERNEL);
@@ -1085,10 +1140,10 @@ static int connect_ring(struct backend_info *be)
return -ENOMEM;
}
- for (i = 0; i < be->blkif->nr_rings; i++) {
+ for (i = 0; i < blkif->nr_rings; i++) {
memset(xspath, 0, xspathsize);
snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend, i);
- err = read_per_ring_refs(&be->blkif->rings[i], xspath);
+ err = read_per_ring_refs(&blkif->rings[i], xspath);
if (err) {
kfree(xspath);
return err;
@@ -1108,10 +1163,17 @@ static struct xenbus_driver xen_blkbk_driver = {
.ids = xen_blkbk_ids,
.probe = xen_blkbk_probe,
.remove = xen_blkbk_remove,
- .otherend_changed = frontend_changed
+ .otherend_changed = frontend_changed,
+ .allow_rebind = true,
+ .reclaim_memory = reclaim_memory,
};
int xen_blkif_xenbus_init(void)
{
return xenbus_register_backend(&xen_blkbk_driver);
}
+
+void xen_blkif_xenbus_fini(void)
+{
+ xenbus_unregister_driver(&xen_blkbk_driver);
+}
generated by cgit (git 2.34.1) at 2025-12-27 19:06:50 +0000