3 files changed, 17 insertions, 11 deletions

diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index b5d842370cc9..f370fc13aea5 100644
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -223,7 +223,7 @@ static void null_softirq_done_fn(struct request *rq)
         blk_end_request_all(rq, 0);
 }
 
-#if defined(CONFIG_SMP) && defined(CONFIG_USE_GENERIC_SMP_HELPERS)
+#ifdef CONFIG_SMP
 
 static void null_ipi_cmd_end_io(void *data)
 {
@@ -260,7 +260,7 @@ static void null_cmd_end_ipi(struct nullb_cmd *cmd)
         put_cpu();
 }
 
-#endif /* CONFIG_SMP && CONFIG_USE_GENERIC_SMP_HELPERS */
+#endif /* CONFIG_SMP */
 
 static inline void null_handle_cmd(struct nullb_cmd *cmd)
 {
@@ -270,7 +270,7 @@ static inline void null_handle_cmd(struct nullb_cmd *cmd)
                 end_cmd(cmd);
                 break;
         case NULL_IRQ_SOFTIRQ:
-#if defined(CONFIG_SMP) && defined(CONFIG_USE_GENERIC_SMP_HELPERS)
+#ifdef CONFIG_SMP
                 null_cmd_end_ipi(cmd);
 #else
                 end_cmd(cmd);
@@ -495,23 +495,23 @@ static int null_add_dev(void)
 
         spin_lock_init(&nullb->lock);
 
+        if (queue_mode == NULL_Q_MQ && use_per_node_hctx)
+                submit_queues = nr_online_nodes;
+
         if (setup_queues(nullb))
                 goto err;
 
         if (queue_mode == NULL_Q_MQ) {
                 null_mq_reg.numa_node = home_node;
                 null_mq_reg.queue_depth = hw_queue_depth;
+                null_mq_reg.nr_hw_queues = submit_queues;
 
                 if (use_per_node_hctx) {
                         null_mq_reg.ops->alloc_hctx = null_alloc_hctx;
                         null_mq_reg.ops->free_hctx = null_free_hctx;
-
-                        null_mq_reg.nr_hw_queues = nr_online_nodes;
                 } else {
                         null_mq_reg.ops->alloc_hctx = blk_mq_alloc_single_hw_queue;
                         null_mq_reg.ops->free_hctx = blk_mq_free_single_hw_queue;
-
-                        null_mq_reg.nr_hw_queues = submit_queues;
                 }
 
                 nullb->q = blk_mq_init_queue(&null_mq_reg, nullb);
@@ -571,7 +571,7 @@ static int __init null_init(void)
 {
         unsigned int i;
 
-#if !defined(CONFIG_SMP) || !defined(CONFIG_USE_GENERIC_SMP_HELPERS)
+#if !defined(CONFIG_SMP)
         if (irqmode == NULL_IRQ_SOFTIRQ) {
                 pr_warn("null_blk: softirq completions not available.\n");
                 pr_warn("null_blk: using direct completions.\n");
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 588479d58f52..6a680d4de7f1 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -199,15 +199,16 @@ static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req)
 
         spin_lock_irqsave(&vblk->vq_lock, flags);
         if (__virtblk_add_req(vblk->vq, vbr, vbr->sg, num) < 0) {
+                virtqueue_kick(vblk->vq);
                 spin_unlock_irqrestore(&vblk->vq_lock, flags);
                 blk_mq_stop_hw_queue(hctx);
-                virtqueue_kick(vblk->vq);
                 return BLK_MQ_RQ_QUEUE_BUSY;
         }
-        spin_unlock_irqrestore(&vblk->vq_lock, flags);
 
         if (last)
                 virtqueue_kick(vblk->vq);
+
+        spin_unlock_irqrestore(&vblk->vq_lock, flags);
         return BLK_MQ_RQ_QUEUE_OK;
 }
 
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 432db1b59b00..c4a4c9006288 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);
 }