xen-blkfront: introduce blkif_set_queue_limits()

blk_mq_update_nr_hw_queues() reset all queue limits to default which it's
not as xen-blkfront expected, introducing blkif_set_queue_limits() to reset
limits with initial correct values.

Signed-off-by: Bob Liu <bob.liu@oracle.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 48 insertions, 38 deletions

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 6a1756d72dcb..f84e220a26e6 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -189,6 +189,8 @@ struct blkfront_info
         struct mutex mutex;
         struct xenbus_device *xbdev;
         struct gendisk *gd;
+        u16 sector_size;
+        unsigned int physical_sector_size;
         int vdevice;
         blkif_vdev_t handle;
         enum blkif_state connected;
@@ -910,9 +912,45 @@ static struct blk_mq_ops blkfront_mq_ops = {
         .map_queue = blk_mq_map_queue,
 };
 
+static void blkif_set_queue_limits(struct blkfront_info *info)
+{
+        struct request_queue *rq = info->rq;
+        struct gendisk *gd = info->gd;
+        unsigned int segments = info->max_indirect_segments ? :
+                                BLKIF_MAX_SEGMENTS_PER_REQUEST;
+
+        queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
+
+        if (info->feature_discard) {
+                queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, rq);
+                blk_queue_max_discard_sectors(rq, get_capacity(gd));
+                rq->limits.discard_granularity = info->discard_granularity;
+                rq->limits.discard_alignment = info->discard_alignment;
+                if (info->feature_secdiscard)
+                        queue_flag_set_unlocked(QUEUE_FLAG_SECERASE, rq);
+        }
+
+        /* Hard sector size and max sectors impersonate the equiv. hardware. */
+        blk_queue_logical_block_size(rq, info->sector_size);
+        blk_queue_physical_block_size(rq, info->physical_sector_size);
+        blk_queue_max_hw_sectors(rq, (segments * XEN_PAGE_SIZE) / 512);
+
+        /* Each segment in a request is up to an aligned page in size. */
+        blk_queue_segment_boundary(rq, PAGE_SIZE - 1);
+        blk_queue_max_segment_size(rq, PAGE_SIZE);
+
+        /* Ensure a merged request will fit in a single I/O ring slot. */
+        blk_queue_max_segments(rq, segments / GRANTS_PER_PSEG);
+
+        /* Make sure buffer addresses are sector-aligned. */
+        blk_queue_dma_alignment(rq, 511);
+
+        /* Make sure we don't use bounce buffers. */
+        blk_queue_bounce_limit(rq, BLK_BOUNCE_ANY);
+}
+
 static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size,
-                                unsigned int physical_sector_size,
-                                unsigned int segments)
+                                unsigned int physical_sector_size)
 {
         struct request_queue *rq;
         struct blkfront_info *info = gd->private_data;
@@ -944,36 +982,11 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size,
         }
 
         rq->queuedata = info;
-        queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
-
-        if (info->feature_discard) {
-                queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, rq);
-                blk_queue_max_discard_sectors(rq, get_capacity(gd));
-                rq->limits.discard_granularity = info->discard_granularity;
-                rq->limits.discard_alignment = info->discard_alignment;
-                if (info->feature_secdiscard)
-                        queue_flag_set_unlocked(QUEUE_FLAG_SECERASE, rq);
-        }
-
-        /* Hard sector size and max sectors impersonate the equiv. hardware. */
-        blk_queue_logical_block_size(rq, sector_size);
-        blk_queue_physical_block_size(rq, physical_sector_size);
-        blk_queue_max_hw_sectors(rq, (segments * XEN_PAGE_SIZE) / 512);
-
-        /* Each segment in a request is up to an aligned page in size. */
-        blk_queue_segment_boundary(rq, PAGE_SIZE - 1);
-        blk_queue_max_segment_size(rq, PAGE_SIZE);
-
-        /* Ensure a merged request will fit in a single I/O ring slot. */
-        blk_queue_max_segments(rq, segments / GRANTS_PER_PSEG);
-
-        /* Make sure buffer addresses are sector-aligned. */
-        blk_queue_dma_alignment(rq, 511);
-
-        /* Make sure we don't use bounce buffers. */
-        blk_queue_bounce_limit(rq, BLK_BOUNCE_ANY);
-
-        gd->queue = rq;
+        info->rq = gd->queue = rq;
+        info->gd = gd;
+        info->sector_size = sector_size;
+        info->physical_sector_size = physical_sector_size;
+        blkif_set_queue_limits(info);
 
         return 0;
 }
@@ -1136,16 +1149,11 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
         gd->private_data = info;
         set_capacity(gd, capacity);
 
-        if (xlvbd_init_blk_queue(gd, sector_size, physical_sector_size,
-                                 info->max_indirect_segments ? :
-                                 BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
+        if (xlvbd_init_blk_queue(gd, sector_size, physical_sector_size)) {
                 del_gendisk(gd);
                 goto release;
         }
 
-        info->rq = gd->queue;
-        info->gd = gd;
-
         xlvbd_flush(info);
 
         if (vdisk_info & VDISK_READONLY)
@@ -2007,6 +2015,8 @@ static int blkif_recover(struct blkfront_info *info)
         struct split_bio *split_bio;
 
         blkfront_gather_backend_features(info);
+        /* Reset limits changed by blk_mq_update_nr_hw_queues(). */
+        blkif_set_queue_limits(info);
         segs = info->max_indirect_segments ? : BLKIF_MAX_SEGMENTS_PER_REQUEST;
         blk_queue_max_segments(info->rq, segs / GRANTS_PER_PSEG);