[Xen-devel] [PATCH 1/6] xen-blkfront: avoid to use start/stop queue

[Ming Lei <ming.lei@xxxxxxxxxx>]

This interfaces will be removed soon, so use quiesce and
unquiesce instead, which should be more safe.

The only one usage will be removed in the following
congestion control patches.

Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: "Roger Pau Monné" <roger.pau@xxxxxxxxxx>
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
 drivers/block/xen-blkfront.c | 22 ++++++++--------------
 1 file changed, 8 insertions(+), 14 deletions(-)

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index c852ed3c01d5..1578befda635 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1187,7 +1187,7 @@ static void xlvbd_release_gendisk(struct blkfront_info 
*info)
                return;
 
        /* No more blkif_request(). */
-       blk_mq_stop_hw_queues(info->rq);
+       blk_mq_quiesce_queue(info->rq);
 
        for (i = 0; i < info->nr_rings; i++) {
                struct blkfront_ring_info *rinfo = &info->rinfo[i];
@@ -1216,8 +1216,10 @@ static void xlvbd_release_gendisk(struct blkfront_info 
*info)
 /* Already hold rinfo->ring_lock. */
 static inline void kick_pending_request_queues_locked(struct 
blkfront_ring_info *rinfo)
 {
-       if (!RING_FULL(&rinfo->ring))
+       if (!RING_FULL(&rinfo->ring)) {
                blk_mq_start_stopped_hw_queues(rinfo->dev_info->rq, true);
+               blk_mq_kick_requeue_list(rinfo->dev_info->rq);
+       }
 }
 
 static void kick_pending_request_queues(struct blkfront_ring_info *rinfo)
@@ -1225,7 +1227,8 @@ static void kick_pending_request_queues(struct 
blkfront_ring_info *rinfo)
        unsigned long flags;
 
        spin_lock_irqsave(&rinfo->ring_lock, flags);
-       kick_pending_request_queues_locked(rinfo);
+       if (!RING_FULL(&rinfo->ring))
+               blk_mq_run_hw_queues(rinfo->dev_info->rq, true);
        spin_unlock_irqrestore(&rinfo->ring_lock, flags);
 }
 
@@ -1346,7 +1349,7 @@ static void blkif_free(struct blkfront_info *info, int 
suspend)
                BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED;
        /* No more blkif_request(). */
        if (info->rq)
-               blk_mq_stop_hw_queues(info->rq);
+               blk_mq_quiesce_queue(info->rq);
 
        for (i = 0; i < info->nr_rings; i++)
                blkif_free_ring(&info->rinfo[i]);
@@ -2018,22 +2021,13 @@ static int blkif_recover(struct blkfront_info *info)
        /* Now safe for us to use the shared ring */
        info->connected = BLKIF_STATE_CONNECTED;
 
-       for (r_index = 0; r_index < info->nr_rings; r_index++) {
-               struct blkfront_ring_info *rinfo;
-
-               rinfo = &info->rinfo[r_index];
-               /* Kick any other new requests queued since we resumed */
-               kick_pending_request_queues(rinfo);
-       }
-
        list_for_each_entry_safe(req, n, &info->requests, queuelist) {
                /* Requeue pending requests (flush or discard) */
                list_del_init(&req->queuelist);
                BUG_ON(req->nr_phys_segments > segs);
                blk_mq_requeue_request(req, false);
        }
-       blk_mq_start_stopped_hw_queues(info->rq, true);
-       blk_mq_kick_requeue_list(info->rq);
+       blk_mq_unquiesce_queue(info->rq);
 
        while ((bio = bio_list_pop(&info->bio_list)) != NULL) {
                /* Traverse the list of pending bios and re-queue them */
-- 
2.9.4


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