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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.c416
1 files changed, 272 insertions, 144 deletions
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index f53cff42f8da..876763f7f13e 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -86,9 +86,11 @@ static void xen_update_blkif_status(struct xen_blkif *blkif)
{
int err;
char name[BLKBACK_NAME_LEN];
+ struct xen_blkif_ring *ring;
+ int i;
/* Not ready to connect? */
- if (!blkif->irq || !blkif->vbd.bdev)
+ if (!blkif->rings || !blkif->rings[0].irq || !blkif->vbd.bdev)
return;
/* Already connected? */
@@ -113,13 +115,55 @@ static void xen_update_blkif_status(struct xen_blkif *blkif)
}
invalidate_inode_pages2(blkif->vbd.bdev->bd_inode->i_mapping);
- blkif->xenblkd = kthread_run(xen_blkif_schedule, blkif, "%s", name);
- if (IS_ERR(blkif->xenblkd)) {
- err = PTR_ERR(blkif->xenblkd);
- blkif->xenblkd = NULL;
- xenbus_dev_error(blkif->be->dev, err, "start xenblkd");
- return;
+ for (i = 0; i < blkif->nr_rings; i++) {
+ ring = &blkif->rings[i];
+ ring->xenblkd = kthread_run(xen_blkif_schedule, ring, "%s-%d", name, i);
+ if (IS_ERR(ring->xenblkd)) {
+ err = PTR_ERR(ring->xenblkd);
+ ring->xenblkd = NULL;
+ xenbus_dev_fatal(blkif->be->dev, err,
+ "start %s-%d xenblkd", name, i);
+ goto out;
+ }
+ }
+ return;
+
+out:
+ while (--i >= 0) {
+ ring = &blkif->rings[i];
+ kthread_stop(ring->xenblkd);
+ }
+ return;
+}
+
+static int xen_blkif_alloc_rings(struct xen_blkif *blkif)
+{
+ unsigned int r;
+
+ blkif->rings = kzalloc(blkif->nr_rings * sizeof(struct xen_blkif_ring), GFP_KERNEL);
+ if (!blkif->rings)
+ return -ENOMEM;
+
+ for (r = 0; r < blkif->nr_rings; r++) {
+ struct xen_blkif_ring *ring = &blkif->rings[r];
+
+ spin_lock_init(&ring->blk_ring_lock);
+ init_waitqueue_head(&ring->wq);
+ 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);
+
+ spin_lock_init(&ring->pending_free_lock);
+ init_waitqueue_head(&ring->pending_free_wq);
+ init_waitqueue_head(&ring->shutdown_wq);
+ ring->blkif = blkif;
+ ring->st_print = jiffies;
+ xen_blkif_get(blkif);
}
+
+ return 0;
}
static struct xen_blkif *xen_blkif_alloc(domid_t domid)
@@ -133,41 +177,25 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid)
return ERR_PTR(-ENOMEM);
blkif->domid = domid;
- spin_lock_init(&blkif->blk_ring_lock);
atomic_set(&blkif->refcnt, 1);
- init_waitqueue_head(&blkif->wq);
init_completion(&blkif->drain_complete);
- atomic_set(&blkif->drain, 0);
- blkif->st_print = jiffies;
- blkif->persistent_gnts.rb_node = NULL;
- spin_lock_init(&blkif->free_pages_lock);
- INIT_LIST_HEAD(&blkif->free_pages);
- INIT_LIST_HEAD(&blkif->persistent_purge_list);
- blkif->free_pages_num = 0;
- atomic_set(&blkif->persistent_gnt_in_use, 0);
- atomic_set(&blkif->inflight, 0);
- INIT_WORK(&blkif->persistent_purge_work, xen_blkbk_unmap_purged_grants);
-
- INIT_LIST_HEAD(&blkif->pending_free);
INIT_WORK(&blkif->free_work, xen_blkif_deferred_free);
- spin_lock_init(&blkif->pending_free_lock);
- init_waitqueue_head(&blkif->pending_free_wq);
- init_waitqueue_head(&blkif->shutdown_wq);
return blkif;
}
-static int xen_blkif_map(struct xen_blkif *blkif, grant_ref_t *gref,
+static int xen_blkif_map(struct xen_blkif_ring *ring, grant_ref_t *gref,
unsigned int nr_grefs, unsigned int evtchn)
{
int err;
+ struct xen_blkif *blkif = ring->blkif;
/* Already connected through? */
- if (blkif->irq)
+ if (ring->irq)
return 0;
err = xenbus_map_ring_valloc(blkif->be->dev, gref, nr_grefs,
- &blkif->blk_ring);
+ &ring->blk_ring);
if (err < 0)
return err;
@@ -175,24 +203,24 @@ static int xen_blkif_map(struct xen_blkif *blkif, grant_ref_t *gref,
case BLKIF_PROTOCOL_NATIVE:
{
struct blkif_sring *sring;
- sring = (struct blkif_sring *)blkif->blk_ring;
- BACK_RING_INIT(&blkif->blk_rings.native, sring,
+ sring = (struct blkif_sring *)ring->blk_ring;
+ BACK_RING_INIT(&ring->blk_rings.native, sring,
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 *)blkif->blk_ring;
- BACK_RING_INIT(&blkif->blk_rings.x86_32, 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);
break;
}
case BLKIF_PROTOCOL_X86_64:
{
struct blkif_x86_64_sring *sring_x86_64;
- sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring;
- BACK_RING_INIT(&blkif->blk_rings.x86_64, 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);
break;
}
@@ -202,13 +230,13 @@ static int xen_blkif_map(struct xen_blkif *blkif, grant_ref_t *gref,
err = bind_interdomain_evtchn_to_irqhandler(blkif->domid, evtchn,
xen_blkif_be_int, 0,
- "blkif-backend", blkif);
+ "blkif-backend", ring);
if (err < 0) {
- xenbus_unmap_ring_vfree(blkif->be->dev, blkif->blk_ring);
- blkif->blk_rings.common.sring = NULL;
+ xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring);
+ ring->blk_rings.common.sring = NULL;
return err;
}
- blkif->irq = err;
+ ring->irq = err;
return 0;
}
@@ -216,50 +244,69 @@ static int xen_blkif_map(struct xen_blkif *blkif, grant_ref_t *gref,
static int xen_blkif_disconnect(struct xen_blkif *blkif)
{
struct pending_req *req, *n;
- int i = 0, j;
+ unsigned int j, r;
- if (blkif->xenblkd) {
- kthread_stop(blkif->xenblkd);
- wake_up(&blkif->shutdown_wq);
- blkif->xenblkd = NULL;
- }
+ for (r = 0; r < blkif->nr_rings; r++) {
+ struct xen_blkif_ring *ring = &blkif->rings[r];
+ unsigned int i = 0;
- /* The above kthread_stop() guarantees that at this point we
- * don't have any discard_io or other_io requests. So, checking
- * for inflight IO is enough.
- */
- if (atomic_read(&blkif->inflight) > 0)
- return -EBUSY;
+ if (ring->xenblkd) {
+ kthread_stop(ring->xenblkd);
+ wake_up(&ring->shutdown_wq);
+ ring->xenblkd = NULL;
+ }
- if (blkif->irq) {
- unbind_from_irqhandler(blkif->irq, blkif);
- blkif->irq = 0;
- }
+ /* The above kthread_stop() guarantees that at this point we
+ * don't have any discard_io or other_io requests. So, checking
+ * for inflight IO is enough.
+ */
+ if (atomic_read(&ring->inflight) > 0)
+ return -EBUSY;
- if (blkif->blk_rings.common.sring) {
- xenbus_unmap_ring_vfree(blkif->be->dev, blkif->blk_ring);
- blkif->blk_rings.common.sring = NULL;
- }
+ if (ring->irq) {
+ unbind_from_irqhandler(ring->irq, ring);
+ ring->irq = 0;
+ }
- /* Remove all persistent grants and the cache of ballooned pages. */
- xen_blkbk_free_caches(blkif);
+ if (ring->blk_rings.common.sring) {
+ xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring);
+ ring->blk_rings.common.sring = NULL;
+ }
- /* Check that there is no request in use */
- list_for_each_entry_safe(req, n, &blkif->pending_free, free_list) {
- list_del(&req->free_list);
+ /* Remove all persistent grants and the cache of ballooned pages. */
+ xen_blkbk_free_caches(ring);
- for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++)
- kfree(req->segments[j]);
+ /* Check that there is no request in use */
+ list_for_each_entry_safe(req, n, &ring->pending_free, free_list) {
+ list_del(&req->free_list);
- for (j = 0; j < MAX_INDIRECT_PAGES; j++)
- kfree(req->indirect_pages[j]);
+ for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++)
+ kfree(req->segments[j]);
- kfree(req);
- i++;
- }
+ for (j = 0; j < MAX_INDIRECT_PAGES; j++)
+ kfree(req->indirect_pages[j]);
+
+ kfree(req);
+ i++;
+ }
- WARN_ON(i != (XEN_BLKIF_REQS_PER_PAGE * blkif->nr_ring_pages));
+ 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->persistent_gnt_c != 0);
+ WARN_ON(i != (XEN_BLKIF_REQS_PER_PAGE * blkif->nr_ring_pages));
+ xen_blkif_put(blkif);
+ }
blkif->nr_ring_pages = 0;
+ /*
+ * blkif->rings was allocated in connect_ring, so we should free it in
+ * here.
+ */
+ kfree(blkif->rings);
+ blkif->rings = NULL;
+ blkif->nr_rings = 0;
return 0;
}
@@ -271,13 +318,6 @@ static void xen_blkif_free(struct xen_blkif *blkif)
xen_vbd_free(&blkif->vbd);
/* Make sure everything is drained before shutting down */
- BUG_ON(blkif->persistent_gnt_c != 0);
- BUG_ON(atomic_read(&blkif->persistent_gnt_in_use) != 0);
- BUG_ON(blkif->free_pages_num != 0);
- BUG_ON(!list_empty(&blkif->persistent_purge_list));
- BUG_ON(!list_empty(&blkif->free_pages));
- BUG_ON(!RB_EMPTY_ROOT(&blkif->persistent_gnts));
-
kmem_cache_free(xen_blkif_cachep, blkif);
}
@@ -296,25 +336,38 @@ int __init xen_blkif_interface_init(void)
* sysfs interface for VBD I/O requests
*/
-#define VBD_SHOW(name, format, args...) \
+#define VBD_SHOW_ALLRING(name, format) \
static ssize_t show_##name(struct device *_dev, \
struct device_attribute *attr, \
char *buf) \
{ \
struct xenbus_device *dev = to_xenbus_device(_dev); \
struct backend_info *be = dev_get_drvdata(&dev->dev); \
+ struct xen_blkif *blkif = be->blkif; \
+ unsigned int i; \
+ unsigned long long result = 0; \
\
- return sprintf(buf, format, ##args); \
+ if (!blkif->rings) \
+ goto out; \
+ \
+ for (i = 0; i < blkif->nr_rings; i++) { \
+ struct xen_blkif_ring *ring = &blkif->rings[i]; \
+ \
+ result += ring->st_##name; \
+ } \
+ \
+out: \
+ return sprintf(buf, format, result); \
} \
static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
-VBD_SHOW(oo_req, "%llu\n", be->blkif->st_oo_req);
-VBD_SHOW(rd_req, "%llu\n", be->blkif->st_rd_req);
-VBD_SHOW(wr_req, "%llu\n", be->blkif->st_wr_req);
-VBD_SHOW(f_req, "%llu\n", be->blkif->st_f_req);
-VBD_SHOW(ds_req, "%llu\n", be->blkif->st_ds_req);
-VBD_SHOW(rd_sect, "%llu\n", be->blkif->st_rd_sect);
-VBD_SHOW(wr_sect, "%llu\n", be->blkif->st_wr_sect);
+VBD_SHOW_ALLRING(oo_req, "%llu\n");
+VBD_SHOW_ALLRING(rd_req, "%llu\n");
+VBD_SHOW_ALLRING(wr_req, "%llu\n");
+VBD_SHOW_ALLRING(f_req, "%llu\n");
+VBD_SHOW_ALLRING(ds_req, "%llu\n");
+VBD_SHOW_ALLRING(rd_sect, "%llu\n");
+VBD_SHOW_ALLRING(wr_sect, "%llu\n");
static struct attribute *xen_vbdstat_attrs[] = {
&dev_attr_oo_req.attr,
@@ -332,6 +385,18 @@ static struct attribute_group xen_vbdstat_group = {
.attrs = xen_vbdstat_attrs,
};
+#define VBD_SHOW(name, format, args...) \
+ static ssize_t show_##name(struct device *_dev, \
+ struct device_attribute *attr, \
+ char *buf) \
+ { \
+ struct xenbus_device *dev = to_xenbus_device(_dev); \
+ struct backend_info *be = dev_get_drvdata(&dev->dev); \
+ \
+ return sprintf(buf, format, ##args); \
+ } \
+ static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
+
VBD_SHOW(physical_device, "%x:%x\n", be->major, be->minor);
VBD_SHOW(mode, "%s\n", be->mode);
@@ -440,11 +505,11 @@ static int xen_blkbk_remove(struct xenbus_device *dev)
dev_set_drvdata(&dev->dev, NULL);
- if (be->blkif) {
+ if (be->blkif)
xen_blkif_disconnect(be->blkif);
- xen_blkif_put(be->blkif);
- }
+ /* Put the reference we set in xen_blkif_alloc(). */
+ xen_blkif_put(be->blkif);
kfree(be->mode);
kfree(be);
return 0;
@@ -553,6 +618,12 @@ static int xen_blkbk_probe(struct xenbus_device *dev,
goto fail;
}
+ /* Multi-queue: advertise how many queues are supported by us.*/
+ err = xenbus_printf(XBT_NIL, dev->nodename,
+ "multi-queue-max-queues", "%u", xenblk_max_queues);
+ if (err)
+ pr_warn("Error writing multi-queue-max-queues\n");
+
/* setup back pointer */
be->blkif->be = be;
@@ -708,8 +779,14 @@ static void frontend_changed(struct xenbus_device *dev,
}
err = connect_ring(be);
- if (err)
+ if (err) {
+ /*
+ * Clean up so that memory resources can be used by
+ * other devices. connect_ring reported already error.
+ */
+ xen_blkif_disconnect(be->blkif);
break;
+ }
xen_update_blkif_status(be->blkif);
break;
@@ -825,50 +902,43 @@ again:
xenbus_transaction_end(xbt, 1);
}
-
-static int connect_ring(struct backend_info *be)
+/*
+ * Each ring may have multi pages, depends on "ring-page-order".
+ */
+static int read_per_ring_refs(struct xen_blkif_ring *ring, const char *dir)
{
- struct xenbus_device *dev = be->dev;
unsigned int ring_ref[XENBUS_MAX_RING_GRANTS];
- unsigned int evtchn, nr_grefs, ring_page_order;
- unsigned int pers_grants;
- char protocol[64] = "";
struct pending_req *req, *n;
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;
- pr_debug("%s %s\n", __func__, dev->otherend);
-
- err = xenbus_scanf(XBT_NIL, dev->otherend, "event-channel", "%u",
+ err = xenbus_scanf(XBT_NIL, dir, "event-channel", "%u",
&evtchn);
if (err != 1) {
err = -EINVAL;
- xenbus_dev_fatal(dev, err, "reading %s/event-channel",
- dev->otherend);
+ xenbus_dev_fatal(dev, err, "reading %s/event-channel", dir);
return err;
}
- pr_info("event-channel %u\n", evtchn);
err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-page-order", "%u",
&ring_page_order);
if (err != 1) {
- err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref",
- "%u", &ring_ref[0]);
+ 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",
- dev->otherend);
+ xenbus_dev_fatal(dev, err, "reading %s/ring-ref", dir);
return err;
}
nr_grefs = 1;
- pr_info("%s:using single page: ring-ref %d\n", dev->otherend,
- ring_ref[0]);
} else {
unsigned int i;
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",
- dev->otherend, ring_page_order,
+ dir, ring_page_order,
xen_blkif_max_ring_order);
return err;
}
@@ -878,52 +948,23 @@ static int connect_ring(struct backend_info *be)
char ring_ref_name[RINGREF_NAME_LEN];
snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i);
- err = xenbus_scanf(XBT_NIL, dev->otherend, ring_ref_name,
+ 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",
- dev->otherend, ring_ref_name);
+ dir, ring_ref_name);
return err;
}
- pr_info("ring-ref%u: %u\n", i, ring_ref[i]);
}
}
-
- be->blkif->blk_protocol = BLKIF_PROTOCOL_DEFAULT;
- err = xenbus_gather(XBT_NIL, dev->otherend, "protocol",
- "%63s", protocol, NULL);
- if (err)
- strcpy(protocol, "unspecified, assuming default");
- else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE))
- be->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;
- else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64))
- be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_64;
- else {
- xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol);
- return -1;
- }
- err = xenbus_gather(XBT_NIL, dev->otherend,
- "feature-persistent", "%u",
- &pers_grants, NULL);
- if (err)
- pers_grants = 0;
-
- be->blkif->vbd.feature_gnt_persistent = pers_grants;
- be->blkif->vbd.overflow_max_grants = 0;
- be->blkif->nr_ring_pages = nr_grefs;
-
- pr_info("ring-pages:%d, event-channel %d, protocol %d (%s) %s\n",
- nr_grefs, evtchn, be->blkif->blk_protocol, protocol,
- pers_grants ? "persistent grants" : "");
+ blkif->nr_ring_pages = nr_grefs;
for (i = 0; i < nr_grefs * XEN_BLKIF_REQS_PER_PAGE; i++) {
req = kzalloc(sizeof(*req), GFP_KERNEL);
if (!req)
goto fail;
- list_add_tail(&req->free_list, &be->blkif->pending_free);
+ list_add_tail(&req->free_list, &ring->pending_free);
for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) {
req->segments[j] = kzalloc(sizeof(*req->segments[0]), GFP_KERNEL);
if (!req->segments[j])
@@ -938,7 +979,7 @@ static int connect_ring(struct backend_info *be)
}
/* Map the shared frame, irq etc. */
- err = xen_blkif_map(be->blkif, ring_ref, nr_grefs, evtchn);
+ 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;
@@ -947,7 +988,7 @@ static int connect_ring(struct backend_info *be)
return 0;
fail:
- list_for_each_entry_safe(req, n, &be->blkif->pending_free, free_list) {
+ list_for_each_entry_safe(req, n, &ring->pending_free, free_list) {
list_del(&req->free_list);
for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) {
if (!req->segments[j])
@@ -962,6 +1003,93 @@ fail:
kfree(req);
}
return -ENOMEM;
+
+}
+
+static int connect_ring(struct backend_info *be)
+{
+ struct xenbus_device *dev = be->dev;
+ unsigned int pers_grants;
+ 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;
+
+ pr_debug("%s %s\n", __func__, dev->otherend);
+
+ be->blkif->blk_protocol = BLKIF_PROTOCOL_DEFAULT;
+ err = xenbus_gather(XBT_NIL, dev->otherend, "protocol",
+ "%63s", protocol, NULL);
+ if (err)
+ strcpy(protocol, "unspecified, assuming default");
+ else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE))
+ be->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;
+ else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64))
+ be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_64;
+ else {
+ xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol);
+ return -ENOSYS;
+ }
+ err = xenbus_gather(XBT_NIL, dev->otherend,
+ "feature-persistent", "%u",
+ &pers_grants, NULL);
+ if (err)
+ pers_grants = 0;
+
+ be->blkif->vbd.feature_gnt_persistent = pers_grants;
+ be->blkif->vbd.overflow_max_grants = 0;
+
+ /*
+ * Read the number of hardware queues from frontend.
+ */
+ err = xenbus_scanf(XBT_NIL, dev->otherend, "multi-queue-num-queues",
+ "%u", &requested_num_queues);
+ if (err < 0) {
+ requested_num_queues = 1;
+ } else {
+ if (requested_num_queues > xenblk_max_queues
+ || requested_num_queues == 0) {
+ /* Buggy or malicious guest. */
+ xenbus_dev_fatal(dev, err,
+ "guest requested %u queues, exceeding the maximum of %u.",
+ requested_num_queues, xenblk_max_queues);
+ return -ENOSYS;
+ }
+ }
+ be->blkif->nr_rings = requested_num_queues;
+ if (xen_blkif_alloc_rings(be->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" : "");
+
+ if (be->blkif->nr_rings == 1)
+ return read_per_ring_refs(&be->blkif->rings[0], dev->otherend);
+ else {
+ xspathsize = strlen(dev->otherend) + xenstore_path_ext_size;
+ xspath = kmalloc(xspathsize, GFP_KERNEL);
+ if (!xspath) {
+ xenbus_dev_fatal(dev, -ENOMEM, "reading ring references");
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < be->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);
+ if (err) {
+ kfree(xspath);
+ return err;
+ }
+ }
+ kfree(xspath);
+ }
+ return 0;
}
static const struct xenbus_device_id xen_blkbk_ids[] = {