4 files changed, 11 insertions, 9 deletions

diff --git a/block/blk-merge.c b/block/blk-merge.c
index fc1ff3b1ea1f..fd3fee81c23c 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -592,7 +592,7 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
         if (q->queue_flags & (1 << QUEUE_FLAG_SG_GAPS)) {
                 struct bio_vec *bprev;
 
-                bprev = &rq->biotail->bi_io_vec[bio->bi_vcnt - 1];
+                bprev = &rq->biotail->bi_io_vec[rq->biotail->bi_vcnt - 1];
                 if (bvec_gap_to_prev(bprev, bio->bi_io_vec[0].bv_offset))
                         return false;
         }
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index d53a764b05ea..be3290cc0644 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -278,9 +278,11 @@ static int bt_get(struct blk_mq_alloc_data *data,
                 /*
                  * We're out of tags on this hardware queue, kick any
                  * pending IO submits before going to sleep waiting for
-                 * some to complete.
+                 * some to complete. Note that hctx can be NULL here for
+                 * reserved tag allocation.
                  */
-                blk_mq_run_hw_queue(hctx, false);
+                if (hctx)
+                        blk_mq_run_hw_queue(hctx, false);
 
                 /*
                  * Retry tag allocation after running the hardware queue,
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 4f4bea21052e..b7b8933ec241 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1938,7 +1938,7 @@ struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
          */
         if (percpu_ref_init(&q->mq_usage_counter, blk_mq_usage_counter_release,
                             PERCPU_REF_INIT_ATOMIC, GFP_KERNEL))
-                goto err_map;
+                goto err_mq_usage;
 
         setup_timer(&q->timeout, blk_mq_rq_timer, (unsigned long) q);
         blk_queue_rq_timeout(q, 30000);
@@ -1981,7 +1981,7 @@ struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
         blk_mq_init_cpu_queues(q, set->nr_hw_queues);
 
         if (blk_mq_init_hw_queues(q, set))
-                goto err_hw;
+                goto err_mq_usage;
 
         mutex_lock(&all_q_mutex);
         list_add_tail(&q->all_q_node, &all_q_list);
@@ -1993,7 +1993,7 @@ struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
 
         return q;
 
-err_hw:
+err_mq_usage:
         blk_cleanup_queue(q);
 err_hctxs:
         kfree(map);
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 6ed2cbe5e8c9..12600bfffca9 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -585,7 +585,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
                                      b->physical_block_size);
 
         t->io_min = max(t->io_min, b->io_min);
-        t->io_opt = lcm(t->io_opt, b->io_opt);
+        t->io_opt = lcm_not_zero(t->io_opt, b->io_opt);
 
         t->cluster &= b->cluster;
         t->discard_zeroes_data &= b->discard_zeroes_data;
@@ -616,7 +616,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
                     b->raid_partial_stripes_expensive);
 
         /* Find lowest common alignment_offset */
-        t->alignment_offset = lcm(t->alignment_offset, alignment)
+        t->alignment_offset = lcm_not_zero(t->alignment_offset, alignment)
                 % max(t->physical_block_size, t->io_min);
 
         /* Verify that new alignment_offset is on a logical block boundary */
@@ -643,7 +643,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
                                                       b->max_discard_sectors);
                 t->discard_granularity = max(t->discard_granularity,
                                              b->discard_granularity);
-                t->discard_alignment = lcm(t->discard_alignment, alignment) %
+                t->discard_alignment = lcm_not_zero(t->discard_alignment, alignment) %
                         t->discard_granularity;
         }