5 files changed, 45 insertions, 37 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index d87be5b4e554..40d654861c33 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2957,8 +2957,6 @@ int kblockd_schedule_delayed_work_on(int cpu, struct delayed_work *dwork,
 }
 EXPORT_SYMBOL(kblockd_schedule_delayed_work_on);
 
-#define PLUG_MAGIC      0x91827364
-
 /**
  * blk_start_plug - initialize blk_plug and track it inside the task_struct
  * @plug:       The &struct blk_plug that needs to be initialized
@@ -2977,7 +2975,6 @@ void blk_start_plug(struct blk_plug *plug)
 {
         struct task_struct *tsk = current;
 
-        plug->magic = PLUG_MAGIC;
         INIT_LIST_HEAD(&plug->list);
         INIT_LIST_HEAD(&plug->mq_list);
         INIT_LIST_HEAD(&plug->cb_list);
@@ -3074,8 +3071,6 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
         LIST_HEAD(list);
         unsigned int depth;
 
-        BUG_ON(plug->magic != PLUG_MAGIC);
-
         flush_plug_callbacks(plug, from_schedule);
 
         if (!list_empty(&plug->mq_list))
diff --git a/block/blk-flush.c b/block/blk-flush.c
index ef608b35d9be..ff87c664b7df 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -223,8 +223,10 @@ static void flush_end_io(struct request *flush_rq, int error)
         struct request *rq, *n;
         unsigned long flags = 0;
 
-        if (q->mq_ops)
+        if (q->mq_ops) {
                 spin_lock_irqsave(&q->mq_flush_lock, flags);
+                q->flush_rq->cmd_flags = 0;
+        }
 
         running = &q->flush_queue[q->flush_running_idx];
         BUG_ON(q->flush_pending_idx == q->flush_running_idx);
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 6c583f9c5b65..b3bf0df0f4c2 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -13,7 +13,7 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
                                              struct bio *bio)
 {
         struct bio_vec bv, bvprv = { NULL };
-        int cluster, high, highprv = 1;
+        int cluster, high, highprv = 1, no_sg_merge;
         unsigned int seg_size, nr_phys_segs;
         struct bio *fbio, *bbio;
         struct bvec_iter iter;
@@ -35,12 +35,21 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
         cluster = blk_queue_cluster(q);
         seg_size = 0;
         nr_phys_segs = 0;
+        no_sg_merge = test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags);
+        high = 0;
         for_each_bio(bio) {
                 bio_for_each_segment(bv, bio, iter) {
                         /*
+                         * If SG merging is disabled, each bio vector is
+                         * a segment
+                         */
+                        if (no_sg_merge)
+                                goto new_segment;
+
+                        /*
                          * the trick here is making sure that a high page is
-                         * never considered part of another segment, since that
-                         * might change with the bounce page.
+                         * never considered part of another segment, since
+                         * that might change with the bounce page.
                          */
                         high = page_to_pfn(bv.bv_page) > queue_bounce_pfn(q);
                         if (!high && !highprv && cluster) {
@@ -84,11 +93,16 @@ void blk_recalc_rq_segments(struct request *rq)
 
 void blk_recount_segments(struct request_queue *q, struct bio *bio)
 {
-        struct bio *nxt = bio->bi_next;
+        if (test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags))
+                bio->bi_phys_segments = bio->bi_vcnt;
+        else {
+                struct bio *nxt = bio->bi_next;
+
+                bio->bi_next = NULL;
+                bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio);
+                bio->bi_next = nxt;
+        }
 
-        bio->bi_next = NULL;
-        bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio);
-        bio->bi_next = nxt;
         bio->bi_flags |= (1 << BIO_SEG_VALID);
 }
 EXPORT_SYMBOL(blk_recount_segments);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index f27fe44230c2..21f952ab3581 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -199,19 +199,12 @@ static void blk_mq_rq_ctx_init(struct request_queue *q, struct blk_mq_ctx *ctx,
         rq->q = q;
         rq->mq_ctx = ctx;
         rq->cmd_flags |= rw_flags;
-        rq->cmd_type = 0;
         /* do not touch atomic flags, it needs atomic ops against the timer */
         rq->cpu = -1;
-        rq->__data_len = 0;
-        rq->__sector = (sector_t) -1;
-        rq->bio = NULL;
-        rq->biotail = NULL;
         INIT_HLIST_NODE(&rq->hash);
         RB_CLEAR_NODE(&rq->rb_node);
-        memset(&rq->flush, 0, max(sizeof(rq->flush), sizeof(rq->elv)));
         rq->rq_disk = NULL;
         rq->part = NULL;
-        rq->start_time = jiffies;
 #ifdef CONFIG_BLK_CGROUP
         rq->rl = NULL;
         set_start_time_ns(rq);
@@ -221,23 +214,16 @@ static void blk_mq_rq_ctx_init(struct request_queue *q, struct blk_mq_ctx *ctx,
 #if defined(CONFIG_BLK_DEV_INTEGRITY)
         rq->nr_integrity_segments = 0;
 #endif
-        rq->ioprio = 0;
         rq->special = NULL;
         /* tag was already set */
         rq->errors = 0;
-        memset(rq->__cmd, 0, sizeof(rq->__cmd));
-        rq->cmd = rq->__cmd;
-        rq->cmd_len = BLK_MAX_CDB;
 
         rq->extra_len = 0;
         rq->sense_len = 0;
         rq->resid_len = 0;
         rq->sense = NULL;
 
-        rq->deadline = 0;
         INIT_LIST_HEAD(&rq->timeout_list);
-        rq->timeout = 0;
-        rq->retries = 0;
         rq->end_io = NULL;
         rq->end_io_data = NULL;
         rq->next_rq = NULL;
@@ -449,8 +435,10 @@ static void blk_mq_start_request(struct request *rq, bool last)
          * complete. So be sure to clear complete again when we start
          * the request, otherwise we'll ignore the completion event.
          */
-        set_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
-        clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
+        if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags))
+                set_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
+        if (test_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags))
+                clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
 
         if (q->dma_drain_size && blk_rq_bytes(rq)) {
                 /*
@@ -553,9 +541,15 @@ void blk_mq_kick_requeue_list(struct request_queue *q)
 }
 EXPORT_SYMBOL(blk_mq_kick_requeue_list);
 
-struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag)
+struct request *blk_mq_tag_to_rq(struct blk_mq_hw_ctx *hctx, unsigned int tag)
 {
-        return tags->rqs[tag];
+        struct request_queue *q = hctx->queue;
+
+        if ((q->flush_rq->cmd_flags & REQ_FLUSH_SEQ) &&
+            q->flush_rq->tag == tag)
+                return q->flush_rq;
+
+        return hctx->tags->rqs[tag];
 }
 EXPORT_SYMBOL(blk_mq_tag_to_rq);
 
@@ -584,7 +578,7 @@ static void blk_mq_timeout_check(void *__data, unsigned long *free_tags)
                 if (tag >= hctx->tags->nr_tags)
                         break;
 
-                rq = blk_mq_tag_to_rq(hctx->tags, tag++);
+                rq = blk_mq_tag_to_rq(hctx, tag++);
                 if (rq->q != hctx->queue)
                         continue;
                 if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags))
@@ -1112,7 +1106,11 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
 static void blk_mq_bio_to_request(struct request *rq, struct bio *bio)
 {
         init_request_from_bio(rq, bio);
-        blk_account_io_start(rq, 1);
+
+        if (blk_do_io_stat(rq)) {
+                rq->start_time = jiffies;
+                blk_account_io_start(rq, 1);
+        }
 }
 
 static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx *hctx,
@@ -1829,6 +1827,9 @@ struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
         q->mq_ops = set->ops;
         q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;
 
+        if (!(set->flags & BLK_MQ_F_SG_MERGE))
+                q->queue_flags |= 1 << QUEUE_FLAG_NO_SG_MERGE;
+
         q->sg_reserved_size = INT_MAX;
 
         INIT_WORK(&q->requeue_work, blk_mq_requeue_work);
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index 26487972ac54..9c28a5b38042 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -205,10 +205,6 @@ int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm)
         if (capable(CAP_SYS_RAWIO))
                 return 0;
 
-        /* if there's no filter set, assume we're filtering everything out */
-        if (!filter)
-                return -EPERM;
-
         /* Anybody who can open the device can do a read-safe command */
         if (test_bit(cmd[0], filter->read_ok))
                 return 0;