Merge branch 'for-linus' of git://git.kernel.dk/linux-block

Pull block layer fixes from Jens Axboe:
 "A small collection of fixes for the current series. It contains:

   - A fix for a use-after-free of a request in blk-mq.  From Ming Lei

   - A fix for a blk-mq bug that could attempt to dereference a NULL rq
     if allocation failed

   - Two xen-blkfront small fixes

   - Cleanup of submit_bio_wait() type uses in the kernel, unifying
     that.  From Kent

   - A fix for 32-bit blkg_rwstat reading.  I apologize for this one
     looking mangled in the shortlog, it's entirely my fault for missing
     an empty line between the description and body of the text"

* 'for-linus' of git://git.kernel.dk/linux-block:
  blk-mq: fix use-after-free of request
  blk-mq: fix dereference of rq->mq_ctx if allocation fails
  block: xen-blkfront: Fix possible NULL ptr dereference
  xen-blkfront: Silence pfn maybe-uninitialized warning
  block: submit_bio_wait() conversions
  Update of blkg_stat and blkg_rwstat may happen in bh context

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 432db1b59b0..c4a4c900628 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -489,7 +489,7 @@ static int blkif_queue_request(struct request *req)
 
 			if ((ring_req->operation == BLKIF_OP_INDIRECT) &&
 			    (i % SEGS_PER_INDIRECT_FRAME == 0)) {
-				unsigned long pfn;
+				unsigned long uninitialized_var(pfn);
 
 				if (segments)
 					kunmap_atomic(segments);
@@ -2011,6 +2011,10 @@ static void blkif_release(struct gendisk *disk, fmode_t mode)
 
 	bdev = bdget_disk(disk, 0);
 
+	if (!bdev) {
+		WARN(1, "Block device %s yanked out from us!\n", disk->disk_name);
+		goto out_mutex;
+	}
 	if (bdev->bd_openers)
 		goto out;
 
@@ -2041,6 +2045,7 @@ static void blkif_release(struct gendisk *disk, fmode_t mode)
 
 out:
 	bdput(bdev);
+out_mutex:
 	mutex_unlock(&blkfront_mutex);
 }