5 files changed, 54 insertions, 49 deletions

diff --git a/block/blk-map.c b/block/blk-map.c
index 5d5dbe47c228..e663ac2d8e68 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -201,12 +201,13 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
         for (i = 0; i < iov_count; i++) {
                 unsigned long uaddr = (unsigned long)iov[i].iov_base;
 
+                if (!iov[i].iov_len)
+                        return -EINVAL;
+
                 if (uaddr & queue_dma_alignment(q)) {
                         unaligned = 1;
                         break;
                 }
-                if (!iov[i].iov_len)
-                        return -EINVAL;
         }
 
         if (unaligned || (q->dma_pad_mask & len) || map_data)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 77b7c26df6b5..74bc4a768f32 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -21,7 +21,7 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
                 return 0;
 
         fbio = bio;
-        cluster = test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
+        cluster = blk_queue_cluster(q);
         seg_size = 0;
         nr_phys_segs = 0;
         for_each_bio(bio) {
@@ -87,7 +87,7 @@ EXPORT_SYMBOL(blk_recount_segments);
 static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio,
                                    struct bio *nxt)
 {
-        if (!test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags))
+        if (!blk_queue_cluster(q))
                 return 0;
 
         if (bio->bi_seg_back_size + nxt->bi_seg_front_size >
@@ -123,7 +123,7 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,
         int nsegs, cluster;
 
         nsegs = 0;
-        cluster = test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
+        cluster = blk_queue_cluster(q);
 
         /*
          * for each bio in rq
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 701859fb9647..36c8c1f2af18 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -126,7 +126,7 @@ void blk_set_default_limits(struct queue_limits *lim)
         lim->alignment_offset = 0;
         lim->io_opt = 0;
         lim->misaligned = 0;
-        lim->no_cluster = 0;
+        lim->cluster = 1;
 }
 EXPORT_SYMBOL(blk_set_default_limits);
 
@@ -229,8 +229,8 @@ void blk_queue_bounce_limit(struct request_queue *q, u64 dma_mask)
 EXPORT_SYMBOL(blk_queue_bounce_limit);
 
 /**
- * blk_queue_max_hw_sectors - set max sectors for a request for this queue
- * @q:  the request queue for the device
+ * blk_limits_max_hw_sectors - set hard and soft limit of max sectors for request
+ * @limits: the queue limits
  * @max_hw_sectors:  max hardware sectors in the usual 512b unit
  *
  * Description:
@@ -244,7 +244,7 @@ EXPORT_SYMBOL(blk_queue_bounce_limit);
  *    per-device basis in /sys/block/<device>/queue/max_sectors_kb.
  *    The soft limit can not exceed max_hw_sectors.
  **/
-void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors)
+void blk_limits_max_hw_sectors(struct queue_limits *limits, unsigned int max_hw_sectors)
 {
         if ((max_hw_sectors << 9) < PAGE_CACHE_SIZE) {
                 max_hw_sectors = 1 << (PAGE_CACHE_SHIFT - 9);
@@ -252,9 +252,23 @@ void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_secto
                        __func__, max_hw_sectors);
         }
 
-        q->limits.max_hw_sectors = max_hw_sectors;
-        q->limits.max_sectors = min_t(unsigned int, max_hw_sectors,
-                                      BLK_DEF_MAX_SECTORS);
+        limits->max_hw_sectors = max_hw_sectors;
+        limits->max_sectors = min_t(unsigned int, max_hw_sectors,
+                                    BLK_DEF_MAX_SECTORS);
+}
+EXPORT_SYMBOL(blk_limits_max_hw_sectors);
+
+/**
+ * blk_queue_max_hw_sectors - set max sectors for a request for this queue
+ * @q:  the request queue for the device
+ * @max_hw_sectors:  max hardware sectors in the usual 512b unit
+ *
+ * Description:
+ *    See description for blk_limits_max_hw_sectors().
+ **/
+void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors)
+{
+        blk_limits_max_hw_sectors(&q->limits, max_hw_sectors);
 }
 EXPORT_SYMBOL(blk_queue_max_hw_sectors);
 
@@ -464,15 +478,6 @@ EXPORT_SYMBOL(blk_queue_io_opt);
 void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b)
 {
         blk_stack_limits(&t->limits, &b->limits, 0);
-
-        if (!t->queue_lock)
-                WARN_ON_ONCE(1);
-        else if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags)) {
-                unsigned long flags;
-                spin_lock_irqsave(t->queue_lock, flags);
-                queue_flag_clear(QUEUE_FLAG_CLUSTER, t);
-                spin_unlock_irqrestore(t->queue_lock, flags);
-        }
 }
 EXPORT_SYMBOL(blk_queue_stack_limits);
 
@@ -545,7 +550,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
         t->io_min = max(t->io_min, b->io_min);
         t->io_opt = lcm(t->io_opt, b->io_opt);
 
-        t->no_cluster |= b->no_cluster;
+        t->cluster &= b->cluster;
         t->discard_zeroes_data &= b->discard_zeroes_data;
 
         /* Physical block size a multiple of the logical block size? */
@@ -641,7 +646,6 @@ void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
                        sector_t offset)
 {
         struct request_queue *t = disk->queue;
-        struct request_queue *b = bdev_get_queue(bdev);
 
         if (bdev_stack_limits(&t->limits, bdev, offset >> 9) < 0) {
                 char top[BDEVNAME_SIZE], bottom[BDEVNAME_SIZE];
@@ -652,17 +656,6 @@ void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
                 printk(KERN_NOTICE "%s: Warning: Device %s is misaligned\n",
                        top, bottom);
         }
-
-        if (!t->queue_lock)
-                WARN_ON_ONCE(1);
-        else if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags)) {
-                unsigned long flags;
-
-                spin_lock_irqsave(t->queue_lock, flags);
-                if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags))
-                        queue_flag_clear(QUEUE_FLAG_CLUSTER, t);
-                spin_unlock_irqrestore(t->queue_lock, flags);
-        }
 }
 EXPORT_SYMBOL(disk_stack_limits);
 
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 013457f47fdc..41fb69150b4d 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -119,7 +119,7 @@ static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *
 
 static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
 {
-        if (test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags))
+        if (blk_queue_cluster(q))
                 return queue_var_show(queue_max_segment_size(q), (page));
 
         return queue_var_show(PAGE_CACHE_SIZE, (page));
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 004be80fd894..381b09bb562b 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -355,6 +355,12 @@ throtl_start_new_slice(struct throtl_data *td, struct throtl_grp *tg, bool rw)
                         tg->slice_end[rw], jiffies);
 }
 
+static inline void throtl_set_slice_end(struct throtl_data *td,
+                struct throtl_grp *tg, bool rw, unsigned long jiffy_end)
+{
+        tg->slice_end[rw] = roundup(jiffy_end, throtl_slice);
+}
+
 static inline void throtl_extend_slice(struct throtl_data *td,
                 struct throtl_grp *tg, bool rw, unsigned long jiffy_end)
 {
@@ -391,6 +397,16 @@ throtl_trim_slice(struct throtl_data *td, struct throtl_grp *tg, bool rw)
         if (throtl_slice_used(td, tg, rw))
                 return;
 
+        /*
+         * A bio has been dispatched. Also adjust slice_end. It might happen
+         * that initially cgroup limit was very low resulting in high
+         * slice_end, but later limit was bumped up and bio was dispached
+         * sooner, then we need to reduce slice_end. A high bogus slice_end
+         * is bad because it does not allow new slice to start.
+         */
+
+        throtl_set_slice_end(td, tg, rw, jiffies + throtl_slice);
+
         time_elapsed = jiffies - tg->slice_start[rw];
 
         nr_slices = time_elapsed / throtl_slice;
@@ -709,26 +725,21 @@ static void throtl_process_limit_change(struct throtl_data *td)
         struct throtl_grp *tg;
         struct hlist_node *pos, *n;
 
-        /*
-         * Make sure atomic_inc() effects from
-         * throtl_update_blkio_group_read_bps(), group of functions are
-         * visible.
-         * Is this required or smp_mb__after_atomic_inc() was suffcient
-         * after the atomic_inc().
-         */
-        smp_rmb();
         if (!atomic_read(&td->limits_changed))
                 return;
 
         throtl_log(td, "limit changed =%d", atomic_read(&td->limits_changed));
 
-        hlist_for_each_entry_safe(tg, pos, n, &td->tg_list, tg_node) {
-                /*
-                 * Do I need an smp_rmb() here to make sure tg->limits_changed
-                 * update is visible. I am relying on smp_rmb() at the
-                 * beginning of function and not putting a new one here.
-                 */
+        /*
+         * Make sure updates from throtl_update_blkio_group_read_bps() group
+         * of functions to tg->limits_changed are visible. We do not
+         * want update td->limits_changed to be visible but update to
+         * tg->limits_changed not being visible yet on this cpu. Hence
+         * the read barrier.
+         */
+        smp_rmb();
 
+        hlist_for_each_entry_safe(tg, pos, n, &td->tg_list, tg_node) {
                 if (throtl_tg_on_rr(tg) && tg->limits_changed) {
                         throtl_log_tg(td, tg, "limit change rbps=%llu wbps=%llu"
                                 " riops=%u wiops=%u", tg->bps[READ],