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

Pull block layer fixes from Jens Axboe:
 "Three small fixes for 4.4 final. Specifically:

   - The segment issue fix from Junichi, where the old IO path does a
     bio limit split before potentially bouncing the pages.  We need to
     do that in the right order, to ensure that limitations are met.

   - A NVMe surprise removal IO hang fix from Keith.

   - A use-after-free in null_blk, introduced by a previous patch in
     this series.  From Mike Krinkin"

* 'for-linus' of git://git.kernel.dk/linux-block:
  null_blk: fix use-after-free error
  block: ensure to split after potentially bouncing a bio
  NVMe: IO ending fixes on surprise removal

block/blk-core.c

@@ -1689,15 +1689,15 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
 	struct request *req;
 	unsigned int request_count = 0;
 
-	blk_queue_split(q, &bio, q->bio_split);
-
 	/*
 	 * low level driver can indicate that it wants pages above a
 	 * certain limit bounced to low memory (ie for highmem, or even
 	 * ISA dma in theory)
 	 */
 	blk_queue_bounce(q, &bio);
 
+	blk_queue_split(q, &bio, q->bio_split);
+
 	if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
 		bio->bi_error = -EIO;
 		bio_endio(bio);

drivers/block/null_blk.c

@@ -219,6 +219,9 @@ static void end_cmd(struct nullb_cmd *cmd)
 {
 	struct request_queue *q = NULL;
 
+	if (cmd->rq)
+		q = cmd->rq->q;
+
 	switch (queue_mode)  {
 	case NULL_Q_MQ:
 		blk_mq_end_request(cmd->rq, 0);
@@ -232,9 +235,6 @@ static void end_cmd(struct nullb_cmd *cmd)
 		goto free_cmd;
 	}
 
-	if (cmd->rq)
-		q = cmd->rq->q;
-
 	/* Restart queue if needed, as we are freeing a tag */
 	if (q && !q->mq_ops && blk_queue_stopped(q)) {
 		unsigned long flags;

drivers/nvme/host/pci.c

@@ -2540,8 +2540,17 @@ static void nvme_ns_remove(struct nvme_ns *ns)
 {
 	bool kill = nvme_io_incapable(ns->dev) && !blk_queue_dying(ns->queue);
 
-	if (kill)
+	if (kill) {
 		blk_set_queue_dying(ns->queue);
+
+		/*
+		 * The controller was shutdown first if we got here through
+		 * device removal. The shutdown may requeue outstanding
+		 * requests. These need to be aborted immediately so
+		 * del_gendisk doesn't block indefinitely for their completion.
+		 */
+		blk_mq_abort_requeue_list(ns->queue);
+	}
 	if (ns->disk->flags & GENHD_FL_UP)
 		del_gendisk(ns->disk);
 	if (kill || !blk_queue_dying(ns->queue)) {
@@ -2977,6 +2986,15 @@ static void nvme_dev_remove(struct nvme_dev *dev)
 {
 	struct nvme_ns *ns, *next;
 
+	if (nvme_io_incapable(dev)) {
+		/*
+		 * If the device is not capable of IO (surprise hot-removal,
+		 * for example), we need to quiesce prior to deleting the
+		 * namespaces. This will end outstanding requests and prevent
+		 * attempts to sync dirty data.
+		 */
+		nvme_dev_shutdown(dev);
+	}
 	list_for_each_entry_safe(ns, next, &dev->namespaces, list)
 		nvme_ns_remove(ns);
 }