Prepare patch for multi hardware queues, the ring number was mandatory set to 1.

Signed-off-by: Arianna Avanzini <avanzini.aria...@gmail.com>
Signed-off-by: Bob Liu <bob....@oracle.com>
---
 drivers/block/xen-blkback/common.h |   3 +-
 drivers/block/xen-blkback/xenbus.c | 368 +++++++++++++++++++++++--------------
 2 files changed, 233 insertions(+), 138 deletions(-)

diff --git a/drivers/block/xen-blkback/common.h 
b/drivers/block/xen-blkback/common.h
index 71863d4..4565deb 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -333,7 +333,8 @@ struct xen_blkif {
        unsigned long long                      st_rd_sect;
        unsigned long long                      st_wr_sect;
        /* Rings for this device */
-       struct xen_blkif_ring ring;
+       struct xen_blkif_ring *rings;
+       unsigned int nr_rings;
 };
 
 struct seg_buf {
diff --git a/drivers/block/xen-blkback/xenbus.c 
b/drivers/block/xen-blkback/xenbus.c
index 4b7bde6..93e5f38 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -78,11 +78,14 @@ static int blkback_name(struct xen_blkif *blkif, char *buf)
 
 static void xen_update_blkif_status(struct xen_blkif *blkif)
 {
-       int err;
+       int err, i;
        char name[TASK_COMM_LEN];
+       char per_ring_name[TASK_COMM_LEN + 4];
+       struct xen_blkif_ring *ring;
 
-       /* Not ready to connect? */
-       if (!blkif->ring.irq || !blkif->vbd.bdev)
+       /* Not ready to connect? Check irq of first ring as the others
+        * should all be the same.*/
+       if (!blkif->rings || !blkif->rings[0].irq || !blkif->vbd.bdev)
                return;
 
        /* Already connected? */
@@ -107,21 +110,108 @@ static void xen_update_blkif_status(struct xen_blkif 
*blkif)
        }
        invalidate_inode_pages2(blkif->vbd.bdev->bd_inode->i_mapping);
 
-       blkif->ring.xenblkd = kthread_run(xen_blkif_schedule, &blkif->ring, 
"%s", name);
-       if (IS_ERR(blkif->ring.xenblkd)) {
-               err = PTR_ERR(blkif->ring.xenblkd);
-               blkif->ring.xenblkd = NULL;
-               xenbus_dev_error(blkif->be->dev, err, "start xenblkd");
-               return;
+       if (blkif->nr_rings == 1) {
+               blkif->rings[0].xenblkd = kthread_run(xen_blkif_schedule, 
&blkif->rings[0], "%s", name);
+               if (IS_ERR(blkif->rings[0].xenblkd)) {
+                       err = PTR_ERR(blkif->rings[0].xenblkd);
+                       blkif->rings[0].xenblkd = NULL;
+                       xenbus_dev_error(blkif->be->dev, err, "start xenblkd");
+                       return;
+               }
+       } else {
+               for (i = 0 ; i < blkif->nr_rings ; i++) {
+                       snprintf(per_ring_name, TASK_COMM_LEN + 1, "%s-%d", 
name, i);
+                       ring = &blkif->rings[i];
+                       ring->xenblkd = kthread_run(xen_blkif_schedule, ring, 
"%s", per_ring_name);
+                       if (IS_ERR(ring->xenblkd)) {
+                               err = PTR_ERR(ring->xenblkd);
+                               ring->xenblkd = NULL;
+                               xenbus_dev_error(blkif->be->dev, err,
+                                               "start %s xenblkd", 
per_ring_name);
+                               return;
+                       }
+               }
        }
 }
 
+static int xen_blkif_alloc_rings(struct xen_blkif *blkif)
+{
+       struct xen_blkif_ring *ring;
+       struct pending_req *req, *n;
+       int i, j, 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++) {
+               ring = &blkif->rings[r];
+               spin_lock_init(&ring->blk_ring_lock);
+               init_waitqueue_head(&ring->wq);
+               ring->st_print = jiffies;
+               ring->persistent_gnts.rb_node = NULL;
+               spin_lock_init(&ring->free_pages_lock);
+               INIT_LIST_HEAD(&ring->free_pages);
+               INIT_LIST_HEAD(&ring->persistent_purge_list);
+               ring->free_pages_num = 0;
+               atomic_set(&ring->persistent_gnt_in_use, 0);
+               atomic_set(&ring->inflight, 0);
+               INIT_WORK(&ring->persistent_purge_work, 
xen_blkbk_unmap_purged_grants);
+               INIT_LIST_HEAD(&ring->pending_free);
+
+               for (i = 0; i < XEN_BLKIF_REQS; i++) {
+                       req = kzalloc(sizeof(*req), GFP_KERNEL);
+                       if (!req)
+                               goto fail;
+                       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])
+                                       goto fail;
+                       }
+                       for (j = 0; j < MAX_INDIRECT_PAGES; j++) {
+                               req->indirect_pages[j] = 
kzalloc(sizeof(*req->indirect_pages[0]),
+                                               GFP_KERNEL);
+                               if (!req->indirect_pages[j])
+                                       goto fail;
+                       }
+               }
+               spin_lock_init(&ring->pending_free_lock);
+               init_waitqueue_head(&ring->pending_free_wq);
+               init_waitqueue_head(&ring->shutdown_wq);
+               ring->blkif = blkif;
+               xen_blkif_get(blkif);
+       }
+       return 0;
+
+fail:
+       while (--r >= 0) {
+               ring = &blkif->rings[r];
+               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])
+                                       break;
+                               kfree(req->segments[j]);
+                       }
+                       for (j = 0; j < MAX_INDIRECT_PAGES; j++) {
+                               if (!req->indirect_pages[j])
+                                       break;
+                               kfree(req->indirect_pages[j]);
+                       }
+                       kfree(req);
+               }
+               xen_blkif_put(blkif);
+       }
+       kfree(blkif->rings);
+       return -ENOMEM;
+}
+
 static struct xen_blkif *xen_blkif_alloc(domid_t domid)
 {
        struct xen_blkif *blkif;
-       struct pending_req *req, *n;
-       int i, j;
-       struct xen_blkif_ring *ring;
 
        BUILD_BUG_ON(MAX_INDIRECT_PAGES > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST);
 
@@ -130,68 +220,18 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid)
                return ERR_PTR(-ENOMEM);
 
        blkif->domid = domid;
-       ring = &blkif->ring;
-       spin_lock_init(&ring->blk_ring_lock);
        atomic_set(&blkif->refcnt, 1);
-       init_waitqueue_head(&ring->wq);
        init_completion(&blkif->drain_complete);
        atomic_set(&blkif->drain, 0);
-       ring->st_print = jiffies;
-       ring->persistent_gnts.rb_node = NULL;
-       spin_lock_init(&ring->free_pages_lock);
-       INIT_LIST_HEAD(&ring->free_pages);
-       INIT_LIST_HEAD(&ring->persistent_purge_list);
-       ring->free_pages_num = 0;
-       atomic_set(&ring->persistent_gnt_in_use, 0);
-       atomic_set(&ring->inflight, 0);
-       INIT_WORK(&ring->persistent_purge_work, xen_blkbk_unmap_purged_grants);
-
-       INIT_LIST_HEAD(&ring->pending_free);
        INIT_WORK(&blkif->free_work, xen_blkif_deferred_free);
 
-       for (i = 0; i < XEN_BLKIF_REQS; i++) {
-               req = kzalloc(sizeof(*req), GFP_KERNEL);
-               if (!req)
-                       goto fail;
-               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])
-                               goto fail;
-               }
-               for (j = 0; j < MAX_INDIRECT_PAGES; j++) {
-                       req->indirect_pages[j] = 
kzalloc(sizeof(*req->indirect_pages[0]),
-                                                        GFP_KERNEL);
-                       if (!req->indirect_pages[j])
-                               goto fail;
-               }
+       blkif->nr_rings = 1;
+       if (xen_blkif_alloc_rings(blkif)) {
+               kmem_cache_free(xen_blkif_cachep, blkif);
+               return ERR_PTR(-ENOMEM);
        }
-       spin_lock_init(&ring->pending_free_lock);
-       init_waitqueue_head(&ring->pending_free_wq);
-       init_waitqueue_head(&ring->shutdown_wq);
 
        return blkif;
-
-fail:
-       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])
-                               break;
-                       kfree(req->segments[j]);
-               }
-               for (j = 0; j < MAX_INDIRECT_PAGES; j++) {
-                       if (!req->indirect_pages[j])
-                               break;
-                       kfree(req->indirect_pages[j]);
-               }
-               kfree(req);
-       }
-
-       kmem_cache_free(xen_blkif_cachep, blkif);
-
-       return ERR_PTR(-ENOMEM);
 }
 
 static int xen_blkif_map(struct xen_blkif_ring *ring, unsigned long 
shared_page,
@@ -249,69 +289,76 @@ static int xen_blkif_map(struct xen_blkif_ring *ring, 
unsigned long shared_page,
 
 static int xen_blkif_disconnect(struct xen_blkif *blkif)
 {
-       struct xen_blkif_ring *ring = &blkif->ring;
+       struct xen_blkif_ring *ring;
+       int i;
+
+       for (i = 0; i < blkif->nr_rings; i++) {
+               ring = &blkif->rings[i];
+               if (ring->xenblkd) {
+                       kthread_stop(ring->xenblkd);
+                       wake_up(&ring->shutdown_wq);
+                       ring->xenblkd = NULL;
+               }
 
-       if (ring->xenblkd) {
-               kthread_stop(ring->xenblkd);
-               wake_up(&ring->shutdown_wq);
-               ring->xenblkd = NULL;
-       }
+               /* 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;
 
-       /* 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 (ring->irq) {
+                       unbind_from_irqhandler(ring->irq, ring);
+                       ring->irq = 0;
+               }
 
-       if (ring->irq) {
-               unbind_from_irqhandler(ring->irq, ring);
-               ring->irq = 0;
-       }
+               if (ring->blk_rings.common.sring) {
+                       xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring);
+                       ring->blk_rings.common.sring = NULL;
+               }
 
-       if (ring->blk_rings.common.sring) {
-               xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring);
-               ring->blk_rings.common.sring = NULL;
+               /* Remove all persistent grants and the cache of ballooned 
pages. */
+               xen_blkbk_free_caches(ring);
        }
 
-       /* Remove all persistent grants and the cache of ballooned pages. */
-       xen_blkbk_free_caches(ring);
-
        return 0;
 }
 
 static void xen_blkif_free(struct xen_blkif *blkif)
 {
        struct pending_req *req, *n;
-       int i = 0, j;
-       struct xen_blkif_ring *ring = &blkif->ring;
+       int i = 0, j, r;
+       struct xen_blkif_ring *ring;
 
        xen_blkif_disconnect(blkif);
        xen_vbd_free(&blkif->vbd);
 
-       /* Make sure everything is drained before shutting down */
-       BUG_ON(ring->persistent_gnt_c != 0);
-       BUG_ON(atomic_read(&ring->persistent_gnt_in_use) != 0);
-       BUG_ON(ring->free_pages_num != 0);
-       BUG_ON(!list_empty(&ring->persistent_purge_list));
-       BUG_ON(!list_empty(&ring->free_pages));
-       BUG_ON(!RB_EMPTY_ROOT(&ring->persistent_gnts));
+       for (r = 0; r < blkif->nr_rings; r++) {
+               ring = &blkif->rings[r];
+               /* Make sure everything is drained before shutting down */
+               BUG_ON(ring->persistent_gnt_c != 0);
+               BUG_ON(atomic_read(&ring->persistent_gnt_in_use) != 0);
+               BUG_ON(ring->free_pages_num != 0);
+               BUG_ON(!list_empty(&ring->persistent_purge_list));
+               BUG_ON(!list_empty(&ring->free_pages));
+               BUG_ON(!RB_EMPTY_ROOT(&ring->persistent_gnts));
 
-       /* 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);
+               /* 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_SEGMENTS; j++)
-                       kfree(req->segments[j]);
+                       for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++)
+                               kfree(req->segments[j]);
 
-               for (j = 0; j < MAX_INDIRECT_PAGES; j++)
-                       kfree(req->indirect_pages[j]);
+                       for (j = 0; j < MAX_INDIRECT_PAGES; j++)
+                               kfree(req->indirect_pages[j]);
 
-               kfree(req);
-               i++;
-       }
+                       kfree(req);
+                       i++;
+               }
 
-       WARN_ON(i != XEN_BLKIF_REQS);
+               WARN_ON(i != XEN_BLKIF_REQS);
+       }
 
        kmem_cache_free(xen_blkif_cachep, blkif);
 }
@@ -339,15 +386,19 @@ int __init xen_blkif_interface_init(void)
                struct xenbus_device *dev = to_xenbus_device(_dev);     \
                struct backend_info *be = dev_get_drvdata(&dev->dev);   \
                struct xen_blkif *blkif = be->blkif;                    \
-               struct xen_blkif_ring *ring = &blkif->ring;             \
+               struct xen_blkif_ring *ring;                            \
+               int i;                                                  \
                                                                        \
-               blkif->st_oo_req = ring->st_oo_req;                     \
-               blkif->st_rd_req = ring->st_rd_req;                     \
-               blkif->st_wr_req = ring->st_wr_req;                     \
-               blkif->st_f_req = ring->st_f_req;                       \
-               blkif->st_ds_req = ring->st_ds_req;                     \
-               blkif->st_rd_sect = ring->st_rd_sect;                   \
-               blkif->st_wr_sect = ring->st_wr_sect;                   \
+               for (i = 0; i < blkif->nr_rings; i++) {                 \
+                       ring = &blkif->rings[i];                        \
+                       blkif->st_oo_req += ring->st_oo_req;            \
+                       blkif->st_rd_req += ring->st_rd_req;            \
+                       blkif->st_wr_req += ring->st_wr_req;            \
+                       blkif->st_f_req += ring->st_f_req;              \
+                       blkif->st_ds_req += ring->st_ds_req;            \
+                       blkif->st_rd_sect += ring->st_rd_sect;          \
+                       blkif->st_wr_sect += ring->st_wr_sect;          \
+               }                                                       \
                                                                        \
                return sprintf(buf, format, ##args);                    \
        }                                                               \
@@ -471,6 +522,7 @@ static int xen_vbd_create(struct xen_blkif *blkif, 
blkif_vdev_t handle,
 static int xen_blkbk_remove(struct xenbus_device *dev)
 {
        struct backend_info *be = dev_get_drvdata(&dev->dev);
+       int i;
 
        DPRINTK("");
 
@@ -487,7 +539,8 @@ static int xen_blkbk_remove(struct xenbus_device *dev)
 
        if (be->blkif) {
                xen_blkif_disconnect(be->blkif);
-               xen_blkif_put(be->blkif);
+               for (i = 0; i < be->blkif->nr_rings; i++)
+                       xen_blkif_put(be->blkif);
        }
 
        kfree(be->mode);
@@ -870,19 +923,13 @@ static int connect_ring(struct backend_info *be)
        unsigned int evtchn;
        unsigned int pers_grants;
        char protocol[64] = "";
-       int err;
+       int err, i;
+       char *xspath;
+       size_t xspathsize;
+       const size_t xenstore_path_ext_size = 11; /* sufficient for 
"/queue-NNN" */
 
        DPRINTK("%s", dev->otherend);
 
-       err = xenbus_gather(XBT_NIL, dev->otherend, "ring-ref", "%lu",
-                           &ring_ref, "event-channel", "%u", &evtchn, NULL);
-       if (err) {
-               xenbus_dev_fatal(dev, err,
-                                "reading %s/ring-ref and event-channel",
-                                dev->otherend);
-               return err;
-       }
-
        be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
        err = xenbus_gather(XBT_NIL, dev->otherend, "protocol",
                            "%63s", protocol, NULL);
@@ -907,19 +954,66 @@ static int connect_ring(struct backend_info *be)
        be->blkif->vbd.feature_gnt_persistent = pers_grants;
        be->blkif->vbd.overflow_max_grants = 0;
 
-       pr_info(DRV_PFX "ring-ref %ld, event-channel %d, protocol %d (%s) %s\n",
-               ring_ref, evtchn, be->blkif->blk_protocol, protocol,
-               pers_grants ? "persistent grants" : "");
+       if (be->blkif->nr_rings == 1) {
+               err = xenbus_gather(XBT_NIL, dev->otherend, "ring-ref", "%lu",
+                               &ring_ref, "event-channel", "%u", &evtchn, 
NULL);
+               if (err) {
+                       xenbus_dev_fatal(dev, err,
+                                       "reading %s/ring-ref and event-channel",
+                                       dev->otherend);
+                       goto out;
+               }
 
-       /* Map the shared frame, irq etc. */
-       err = xen_blkif_map(&be->blkif->ring, ring_ref, evtchn);
-       if (err) {
-               xenbus_dev_fatal(dev, err, "mapping ring-ref %lu port %u",
-                                ring_ref, evtchn);
-               return err;
-       }
+               pr_info(DRV_PFX "ring-ref %ld, event-channel %d, protocol %d 
(%s) %s\n",
+                               ring_ref, evtchn, be->blkif->blk_protocol, 
protocol,
+                               pers_grants ? "persistent grants" : "");
 
+               /* Map the shared frame, irq etc. */
+               err = xen_blkif_map(&be->blkif->rings[0], ring_ref, evtchn);
+               if (err) {
+                       xenbus_dev_fatal(dev, err, "mapping ring-ref %lu port 
%u",
+                                       ring_ref, evtchn);
+                       goto out;
+               }
+       } else {
+               xspathsize = strlen(dev->otherend) + xenstore_path_ext_size;
+               xspath = kzalloc(xspathsize, GFP_KERNEL);
+               if (!xspath) {
+                       xenbus_dev_fatal(dev, -ENOMEM, "reading ring 
references");
+                       err = -ENOMEM;
+                       goto out;
+               }
+
+               for (i = 0; i < be->blkif->nr_rings; i++) {
+                       memset(xspath, 0, xspathsize);
+                       snprintf(xspath, xspathsize, "%s/queue-%u", 
dev->otherend, i);
+                       err = xenbus_gather(XBT_NIL, xspath, "ring-ref", "%lu",
+                                       &ring_ref, "event-channel", "%u", 
&evtchn, NULL);
+                       if (err) {
+                               xenbus_dev_fatal(dev, err,
+                                               "reading %s %d/ring-ref and 
event-channel",
+                                               xspath, i);
+                               kfree(xspath);
+                               goto out;
+                       }
+
+                       pr_info(DRV_PFX "ring-ref %ld, event-channel %d, 
protocol %d (%s) %s\n",
+                                       ring_ref, evtchn, 
be->blkif->blk_protocol, protocol,
+                                       pers_grants ? "persistent grants" : "");
+                       /* Map the shared frame, irq etc. */
+                       err = xen_blkif_map(&be->blkif->rings[i], ring_ref, 
evtchn);
+                       if (err) {
+                               xenbus_dev_fatal(dev, err, "mapping ring-ref 
%lu port %u",
+                                               ring_ref, evtchn);
+                               kfree(xspath);
+                               goto out;
+                       }
+               }
+               kfree(xspath);
+       }
        return 0;
+out:
+       return err;
 }
 
 static const struct xenbus_device_id xen_blkbk_ids[] = {
-- 
1.8.3.1


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