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authorJens Axboe <axboe@fb.com>2014-12-08 08:49:06 -0700
committerJens Axboe <axboe@fb.com>2014-12-08 08:49:06 -0700
commit080ff3511450fd73948697fef34a3cc382675b59 (patch)
tree8ce40121a12ef2d48c0c094f3b3751069490a29b /block/blk-mq-tag.c
parentb32232073e8061b41258bff2a10a06a91677480a (diff)
downloadkernel-080ff3511450fd73948697fef34a3cc382675b59.tar.gz
blk-mq: re-check for available tags after running the hardware queue
If we run out of tags and have to sleep, we run the hardware queue to kick pending IO into gear. During that run, we may have completed requests, so re-check if we have free tags before going to sleep. Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/blk-mq-tag.c')
-rw-r--r--block/blk-mq-tag.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index eb55492e6875..bab4bff15f42 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -261,6 +261,14 @@ static int bt_get(struct blk_mq_alloc_data *data,
*/
blk_mq_run_hw_queue(hctx, false);
+ /*
+ * Retry tag allocation after running the hardware queue,
+ * as running the queue may also have found completions.
+ */
+ tag = __bt_get(hctx, bt, last_tag);
+ if (tag != -1)
+ break;
+
blk_mq_put_ctx(data->ctx);
io_schedule();