Merge branch 'for-3.20/core' into for-3.20/drivers

We need the tagging changes for the libata conversion.

16 files changed, 146 insertions, 62 deletions

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 8411be3c19d3..715e948f58a4 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -283,23 +283,45 @@ static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
  * @sector:     start sector
  * @nr_sects:   number of sectors to write
  * @gfp_mask:   memory allocation flags (for bio_alloc)
+ * @discard:    whether to discard the block range
  *
  * Description:
- *  Generate and issue number of bios with zerofiled pages.
+
+ *  Zero-fill a block range.  If the discard flag is set and the block
+ *  device guarantees that subsequent READ operations to the block range
+ *  in question will return zeroes, the blocks will be discarded. Should
+ *  the discard request fail, if the discard flag is not set, or if
+ *  discard_zeroes_data is not supported, this function will resort to
+ *  zeroing the blocks manually, thus provisioning (allocating,
+ *  anchoring) them. If the block device supports the WRITE SAME command
+ *  blkdev_issue_zeroout() will use it to optimize the process of
+ *  clearing the block range. Otherwise the zeroing will be performed
+ *  using regular WRITE calls.
  */
 
 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
-                         sector_t nr_sects, gfp_t gfp_mask)
+                         sector_t nr_sects, gfp_t gfp_mask, bool discard)
 {
+        struct request_queue *q = bdev_get_queue(bdev);
+        unsigned char bdn[BDEVNAME_SIZE];
+
+        if (discard && blk_queue_discard(q) && q->limits.discard_zeroes_data) {
+
+                if (!blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, 0))
+                        return 0;
+
+                bdevname(bdev, bdn);
+                pr_warn("%s: DISCARD failed. Manually zeroing.\n", bdn);
+        }
+
         if (bdev_write_same(bdev)) {
-                unsigned char bdn[BDEVNAME_SIZE];
 
                 if (!blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
                                              ZERO_PAGE(0)))
                         return 0;
 
                 bdevname(bdev, bdn);
-                pr_err("%s: WRITE SAME failed. Manually zeroing.\n", bdn);
+                pr_warn("%s: WRITE SAME failed. Manually zeroing.\n", bdn);
         }
 
         return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 60c9d4a93fe4..e3387a74a9a2 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -140,35 +140,39 @@ static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx,
         return atomic_read(&hctx->nr_active) < depth;
 }
 
-static int __bt_get_word(struct blk_align_bitmap *bm, unsigned int last_tag)
+static int __bt_get_word(struct blk_align_bitmap *bm, unsigned int last_tag,
+                         bool nowrap)
 {
-        int tag, org_last_tag, end;
-        bool wrap = last_tag != 0;
+        int tag, org_last_tag = last_tag;
 
-        org_last_tag = last_tag;
-        end = bm->depth;
-        do {
-restart:
-                tag = find_next_zero_bit(&bm->word, end, last_tag);
-                if (unlikely(tag >= end)) {
+        while (1) {
+                tag = find_next_zero_bit(&bm->word, bm->depth, last_tag);
+                if (unlikely(tag >= bm->depth)) {
                         /*
-                         * We started with an offset, start from 0 to
+                         * We started with an offset, and we didn't reset the
+                         * offset to 0 in a failure case, so start from 0 to
                          * exhaust the map.
                          */
-                        if (wrap) {
-                                wrap = false;
-                                end = org_last_tag;
-                                last_tag = 0;
-                                goto restart;
+                        if (org_last_tag && last_tag && !nowrap) {
+                                last_tag = org_last_tag = 0;
+                                continue;
                         }
                         return -1;
                 }
+
+                if (!test_and_set_bit(tag, &bm->word))
+                        break;
+
                 last_tag = tag + 1;
-        } while (test_and_set_bit(tag, &bm->word));
+                if (last_tag >= bm->depth - 1)
+                        last_tag = 0;
+        }
 
         return tag;
 }
 
+#define BT_ALLOC_RR(tags) (tags->alloc_policy == BLK_TAG_ALLOC_RR)
+
 /*
  * Straight forward bitmap tag implementation, where each bit is a tag
  * (cleared == free, and set == busy). The small twist is using per-cpu
@@ -181,7 +185,7 @@ restart:
  * until the map is exhausted.
  */
 static int __bt_get(struct blk_mq_hw_ctx *hctx, struct blk_mq_bitmap_tags *bt,
-                    unsigned int *tag_cache)
+                    unsigned int *tag_cache, struct blk_mq_tags *tags)
 {
         unsigned int last_tag, org_last_tag;
         int index, i, tag;
@@ -193,15 +197,24 @@ static int __bt_get(struct blk_mq_hw_ctx *hctx, struct blk_mq_bitmap_tags *bt,
         index = TAG_TO_INDEX(bt, last_tag);
 
         for (i = 0; i < bt->map_nr; i++) {
-                tag = __bt_get_word(&bt->map[index], TAG_TO_BIT(bt, last_tag));
+                tag = __bt_get_word(&bt->map[index], TAG_TO_BIT(bt, last_tag),
+                                    BT_ALLOC_RR(tags));
                 if (tag != -1) {
                         tag += (index << bt->bits_per_word);
                         goto done;
                 }
 
-                last_tag = 0;
-                if (++index >= bt->map_nr)
+                /*
+                 * Jump to next index, and reset the last tag to be the
+                 * first tag of that index
+                 */
+                index++;
+                last_tag = (index << bt->bits_per_word);
+
+                if (index >= bt->map_nr) {
                         index = 0;
+                        last_tag = 0;
+                }
         }
 
         *tag_cache = 0;
@@ -212,7 +225,7 @@ static int __bt_get(struct blk_mq_hw_ctx *hctx, struct blk_mq_bitmap_tags *bt,
          * up using the specific cached tag.
          */
 done:
-        if (tag == org_last_tag) {
+        if (tag == org_last_tag || unlikely(BT_ALLOC_RR(tags))) {
                 last_tag = tag + 1;
                 if (last_tag >= bt->depth - 1)
                         last_tag = 0;
@@ -241,13 +254,13 @@ static struct bt_wait_state *bt_wait_ptr(struct blk_mq_bitmap_tags *bt,
 static int bt_get(struct blk_mq_alloc_data *data,
                 struct blk_mq_bitmap_tags *bt,
                 struct blk_mq_hw_ctx *hctx,
-                unsigned int *last_tag)
+                unsigned int *last_tag, struct blk_mq_tags *tags)
 {
         struct bt_wait_state *bs;
         DEFINE_WAIT(wait);
         int tag;
 
-        tag = __bt_get(hctx, bt, last_tag);
+        tag = __bt_get(hctx, bt, last_tag, tags);
         if (tag != -1)
                 return tag;
 
@@ -258,7 +271,7 @@ static int bt_get(struct blk_mq_alloc_data *data,
         do {
                 prepare_to_wait(&bs->wait, &wait, TASK_UNINTERRUPTIBLE);
 
-                tag = __bt_get(hctx, bt, last_tag);
+                tag = __bt_get(hctx, bt, last_tag, tags);
                 if (tag != -1)
                         break;
 
@@ -273,7 +286,7 @@ static int bt_get(struct blk_mq_alloc_data *data,
                  * Retry tag allocation after running the hardware queue,
                  * as running the queue may also have found completions.
                  */
-                tag = __bt_get(hctx, bt, last_tag);
+                tag = __bt_get(hctx, bt, last_tag, tags);
                 if (tag != -1)
                         break;
 
@@ -304,7 +317,7 @@ static unsigned int __blk_mq_get_tag(struct blk_mq_alloc_data *data)
         int tag;
 
         tag = bt_get(data, &data->hctx->tags->bitmap_tags, data->hctx,
-                        &data->ctx->last_tag);
+                        &data->ctx->last_tag, data->hctx->tags);
         if (tag >= 0)
                 return tag + data->hctx->tags->nr_reserved_tags;
 
@@ -320,7 +333,8 @@ static unsigned int __blk_mq_get_reserved_tag(struct blk_mq_alloc_data *data)
                 return BLK_MQ_TAG_FAIL;
         }
 
-        tag = bt_get(data, &data->hctx->tags->breserved_tags, NULL, &zero);
+        tag = bt_get(data, &data->hctx->tags->breserved_tags, NULL, &zero,
+                data->hctx->tags);
         if (tag < 0)
                 return BLK_MQ_TAG_FAIL;
 
@@ -392,7 +406,8 @@ void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, unsigned int tag,
 
                 BUG_ON(real_tag >= tags->nr_tags);
                 bt_clear_tag(&tags->bitmap_tags, real_tag);
-                *last_tag = real_tag;
+                if (likely(tags->alloc_policy == BLK_TAG_ALLOC_FIFO))
+                        *last_tag = real_tag;
         } else {
                 BUG_ON(tag >= tags->nr_reserved_tags);
                 bt_clear_tag(&tags->breserved_tags, tag);
@@ -529,10 +544,12 @@ static void bt_free(struct blk_mq_bitmap_tags *bt)
 }
 
 static struct blk_mq_tags *blk_mq_init_bitmap_tags(struct blk_mq_tags *tags,
-                                                   int node)
+                                                   int node, int alloc_policy)
 {
         unsigned int depth = tags->nr_tags - tags->nr_reserved_tags;
 
+        tags->alloc_policy = alloc_policy;
+
         if (bt_alloc(&tags->bitmap_tags, depth, node, false))
                 goto enomem;
         if (bt_alloc(&tags->breserved_tags, tags->nr_reserved_tags, node, true))
@@ -546,7 +563,8 @@ enomem:
 }
 
 struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
-                                     unsigned int reserved_tags, int node)
+                                     unsigned int reserved_tags,
+                                     int node, int alloc_policy)
 {
         struct blk_mq_tags *tags;
 
@@ -562,7 +580,7 @@ struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
         tags->nr_tags = total_tags;
         tags->nr_reserved_tags = reserved_tags;
 
-        return blk_mq_init_bitmap_tags(tags, node);
+        return blk_mq_init_bitmap_tags(tags, node, alloc_policy);
 }
 
 void blk_mq_free_tags(struct blk_mq_tags *tags)
diff --git a/block/blk-mq-tag.h b/block/blk-mq-tag.h
index a6fa0fc9d41a..90767b370308 100644
--- a/block/blk-mq-tag.h
+++ b/block/blk-mq-tag.h
@@ -42,10 +42,12 @@ struct blk_mq_tags {
 
         struct request **rqs;
         struct list_head page_list;
+
+        int alloc_policy;
 };
 
 
-extern struct blk_mq_tags *blk_mq_init_tags(unsigned int nr_tags, unsigned int reserved_tags, int node);
+extern struct blk_mq_tags *blk_mq_init_tags(unsigned int nr_tags, unsigned int reserved_tags, int node, int alloc_policy);
 extern void blk_mq_free_tags(struct blk_mq_tags *tags);
 
 extern unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index a7d4a988516f..eb8e694fda06 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1374,7 +1374,8 @@ static struct blk_mq_tags *blk_mq_init_rq_map(struct blk_mq_tag_set *set,
         size_t rq_size, left;
 
         tags = blk_mq_init_tags(set->queue_depth, set->reserved_tags,
-                                set->numa_node);
+                                set->numa_node,
+                                BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags));
         if (!tags)
                 return NULL;
 
diff --git a/block/blk-tag.c b/block/blk-tag.c
index a185b86741e5..f0344e6939d5 100644
--- a/block/blk-tag.c
+++ b/block/blk-tag.c
@@ -119,7 +119,7 @@ fail:
 }
 
 static struct blk_queue_tag *__blk_queue_init_tags(struct request_queue *q,
-                                                   int depth)
+                                                int depth, int alloc_policy)
 {
         struct blk_queue_tag *tags;
 
@@ -131,6 +131,8 @@ static struct blk_queue_tag *__blk_queue_init_tags(struct request_queue *q,
                 goto fail;
 
         atomic_set(&tags->refcnt, 1);
+        tags->alloc_policy = alloc_policy;
+        tags->next_tag = 0;
         return tags;
 fail:
         kfree(tags);
@@ -140,10 +142,11 @@ fail:
 /**
  * blk_init_tags - initialize the tag info for an external tag map
  * @depth:      the maximum queue depth supported
+ * @alloc_policy: tag allocation policy
  **/
-struct blk_queue_tag *blk_init_tags(int depth)
+struct blk_queue_tag *blk_init_tags(int depth, int alloc_policy)
 {
-        return __blk_queue_init_tags(NULL, depth);
+        return __blk_queue_init_tags(NULL, depth, alloc_policy);
 }
 EXPORT_SYMBOL(blk_init_tags);
 
@@ -152,19 +155,20 @@ EXPORT_SYMBOL(blk_init_tags);
  * @q:  the request queue for the device
  * @depth:  the maximum queue depth supported
  * @tags: the tag to use
+ * @alloc_policy: tag allocation policy
  *
  * Queue lock must be held here if the function is called to resize an
  * existing map.
  **/
 int blk_queue_init_tags(struct request_queue *q, int depth,
-                        struct blk_queue_tag *tags)
+                        struct blk_queue_tag *tags, int alloc_policy)
 {
         int rc;
 
         BUG_ON(tags && q->queue_tags && tags != q->queue_tags);
 
         if (!tags && !q->queue_tags) {
-                tags = __blk_queue_init_tags(q, depth);
+                tags = __blk_queue_init_tags(q, depth, alloc_policy);
 
                 if (!tags)
                         return -ENOMEM;
@@ -344,9 +348,21 @@ int blk_queue_start_tag(struct request_queue *q, struct request *rq)
         }
 
         do {
-                tag = find_first_zero_bit(bqt->tag_map, max_depth);
-                if (tag >= max_depth)
-                        return 1;
+                if (bqt->alloc_policy == BLK_TAG_ALLOC_FIFO) {
+                        tag = find_first_zero_bit(bqt->tag_map, max_depth);
+                        if (tag >= max_depth)
+                                return 1;
+                } else {
+                        int start = bqt->next_tag;
+                        int size = min_t(int, bqt->max_depth, max_depth + start);
+                        tag = find_next_zero_bit(bqt->tag_map, size, start);
+                        if (tag >= size && start + size > bqt->max_depth) {
+                                size = start + size - bqt->max_depth;
+                                tag = find_first_zero_bit(bqt->tag_map, size);
+                        }
+                        if (tag >= size)
+                                return 1;
+                }
 
         } while (test_and_set_bit_lock(tag, bqt->tag_map));
         /*
@@ -354,6 +370,7 @@ int blk_queue_start_tag(struct request_queue *q, struct request *rq)
          * See blk_queue_end_tag for details.
          */
 
+        bqt->next_tag = (tag + 1) % bqt->max_depth;
         rq->cmd_flags |= REQ_QUEUED;
         rq->tag = tag;
         bqt->tag_index[tag] = rq;
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 6f2751d305de..b9abdca84c17 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3656,12 +3656,17 @@ static struct cfq_queue *
 cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic,
               struct bio *bio, gfp_t gfp_mask)
 {
-        const int ioprio_class = IOPRIO_PRIO_CLASS(cic->ioprio);
-        const int ioprio = IOPRIO_PRIO_DATA(cic->ioprio);
+        int ioprio_class = IOPRIO_PRIO_CLASS(cic->ioprio);
+        int ioprio = IOPRIO_PRIO_DATA(cic->ioprio);
         struct cfq_queue **async_cfqq = NULL;
         struct cfq_queue *cfqq = NULL;
 
         if (!is_sync) {
+                if (!ioprio_valid(cic->ioprio)) {
+                        struct task_struct *tsk = current;
+                        ioprio = task_nice_ioprio(tsk);
+                        ioprio_class = task_nice_ioclass(tsk);
+                }
                 async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio);
                 cfqq = *async_cfqq;
         }
diff --git a/block/ioctl.c b/block/ioctl.c
index 6c7bf903742f..7d8befde2aca 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -198,7 +198,7 @@ static int blk_ioctl_zeroout(struct block_device *bdev, uint64_t start,
         if (start + len > (i_size_read(bdev->bd_inode) >> 9))
                 return -EINVAL;
 
-        return blkdev_issue_zeroout(bdev, start, len, GFP_KERNEL);
+        return blkdev_issue_zeroout(bdev, start, len, GFP_KERNEL, false);
 }
 
 static int put_ushort(unsigned long arg, unsigned short val)
diff --git a/block/partitions/check.c b/block/partitions/check.c
index 9ac1df74f699..16118d11dbfc 100644
--- a/block/partitions/check.c
+++ b/block/partitions/check.c
@@ -184,12 +184,12 @@ check_partition(struct gendisk *hd, struct block_device *bdev)
         if (err)
         /* The partition is unrecognized. So report I/O errors if there were any */
                 res = err;
-        if (!res)
-                strlcat(state->pp_buf, " unknown partition table\n", PAGE_SIZE);
-        else if (warn_no_part)
-                strlcat(state->pp_buf, " unable to read partition table\n", PAGE_SIZE);
-
-        printk(KERN_INFO "%s", state->pp_buf);
+        if (res) {
+                if (warn_no_part)
+                        strlcat(state->pp_buf,
+                                " unable to read partition table\n", PAGE_SIZE);
+                printk(KERN_INFO "%s", state->pp_buf);
+        }
 
         free_page((unsigned long)state->pp_buf);
         free_partitions(state);
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index d169b4a79267..cee20354ac37 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -1388,7 +1388,7 @@ int drbd_submit_peer_request(struct drbd_device *device,
                 list_add_tail(&peer_req->w.list, &device->active_ee);
                 spin_unlock_irq(&device->resource->req_lock);
                 if (blkdev_issue_zeroout(device->ldev->backing_bdev,
-                        sector, data_size >> 9, GFP_NOIO))
+                        sector, data_size >> 9, GFP_NOIO, false))
                         peer_req->flags |= EE_WAS_ERROR;
                 drbd_endio_write_sec_final(peer_req);
                 return 0;
diff --git a/drivers/block/osdblk.c b/drivers/block/osdblk.c
index 79aa179305b5..e22942596207 100644
--- a/drivers/block/osdblk.c
+++ b/drivers/block/osdblk.c
@@ -423,7 +423,7 @@ static int osdblk_init_disk(struct osdblk_device *osdev)
         }
 
         /* switch queue to TCQ mode; allocate tag map */
-        rc = blk_queue_init_tags(q, OSDBLK_MAX_REQ, NULL);
+        rc = blk_queue_init_tags(q, OSDBLK_MAX_REQ, NULL, BLK_TAG_ALLOC_FIFO);
         if (rc) {
                 blk_cleanup_queue(q);
                 put_disk(disk);
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 9ea95dd3e260..49ab11508286 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2188,6 +2188,8 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost)
         shost->tag_set.cmd_size = cmd_size;
         shost->tag_set.numa_node = NUMA_NO_NODE;
         shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
+        shost->tag_set.flags |=
+                BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
         shost->tag_set.driver_data = shost;
 
         return blk_mq_alloc_tag_set(&shost->tag_set);
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 983aed10ff2f..921a8c897eb2 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -290,7 +290,8 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
         if (!shost_use_blk_mq(sdev->host) &&
             (shost->bqt || shost->hostt->use_blk_tags)) {
                 blk_queue_init_tags(sdev->request_queue,
-                                    sdev->host->cmd_per_lun, shost->bqt);
+                                    sdev->host->cmd_per_lun, shost->bqt,
+                                    shost->hostt->tag_alloc_policy);
         }
         scsi_change_queue_depth(sdev, sdev->host->cmd_per_lun);
 
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 5b6500c77ed2..86b08b1a5eba 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -147,6 +147,8 @@ enum {
         BLK_MQ_F_SG_MERGE       = 1 << 2,
         BLK_MQ_F_SYSFS_UP       = 1 << 3,
         BLK_MQ_F_DEFER_ISSUE    = 1 << 4,
+        BLK_MQ_F_ALLOC_POLICY_START_BIT = 8,
+        BLK_MQ_F_ALLOC_POLICY_BITS = 1,
 
         BLK_MQ_S_STOPPED        = 0,
         BLK_MQ_S_TAG_ACTIVE     = 1,
@@ -155,6 +157,12 @@ enum {
 
         BLK_MQ_CPU_WORK_BATCH   = 8,
 };
+#define BLK_MQ_FLAG_TO_ALLOC_POLICY(flags) \
+        ((flags >> BLK_MQ_F_ALLOC_POLICY_START_BIT) & \
+                ((1 << BLK_MQ_F_ALLOC_POLICY_BITS) - 1))
+#define BLK_ALLOC_POLICY_TO_MQ_FLAG(policy) \
+        ((policy & ((1 << BLK_MQ_F_ALLOC_POLICY_BITS) - 1)) \
+                << BLK_MQ_F_ALLOC_POLICY_START_BIT)
 
 struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *);
 void blk_mq_finish_init(struct request_queue *q);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index e9086be6d9a0..6f388fd1c11c 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -272,7 +272,11 @@ struct blk_queue_tag {
         int max_depth;                  /* what we will send to device */
         int real_max_depth;             /* what the array can hold */
         atomic_t refcnt;                /* map can be shared */
+        int alloc_policy;               /* tag allocation policy */
+        int next_tag;                   /* next tag */
 };
+#define BLK_TAG_ALLOC_FIFO 0 /* allocate starting from 0 */
+#define BLK_TAG_ALLOC_RR 1 /* allocate starting from last allocated tag */
 
 #define BLK_SCSI_MAX_CMDS       (256)
 #define BLK_SCSI_CMD_PER_LONG   (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8))
@@ -1139,11 +1143,11 @@ static inline bool blk_needs_flush_plug(struct task_struct *tsk)
 extern int blk_queue_start_tag(struct request_queue *, struct request *);
 extern struct request *blk_queue_find_tag(struct request_queue *, int);
 extern void blk_queue_end_tag(struct request_queue *, struct request *);
-extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *);
+extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *, int);
 extern void blk_queue_free_tags(struct request_queue *);
 extern int blk_queue_resize_tags(struct request_queue *, int);
 extern void blk_queue_invalidate_tags(struct request_queue *);
-extern struct blk_queue_tag *blk_init_tags(int);
+extern struct blk_queue_tag *blk_init_tags(int, int);
 extern void blk_free_tags(struct blk_queue_tag *);
 
 static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt,
@@ -1162,7 +1166,7 @@ extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
                 sector_t nr_sects, gfp_t gfp_mask, struct page *page);
 extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
-                        sector_t nr_sects, gfp_t gfp_mask);
+                sector_t nr_sects, gfp_t gfp_mask, bool discard);
 static inline int sb_issue_discard(struct super_block *sb, sector_t block,
                 sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags)
 {
@@ -1176,7 +1180,7 @@ static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
         return blkdev_issue_zeroout(sb->s_bdev,
                                     block << (sb->s_blocksize_bits - 9),
                                     nr_blocks << (sb->s_blocksize_bits - 9),
-                                    gfp_mask);
+                                    gfp_mask, true);
 }
 
 extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 019e66858ce6..e113c757d555 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -402,6 +402,9 @@ struct scsi_host_template {
          */
         unsigned char present;
 
+        /* If use block layer to manage tags, this is tag allocation policy */
+        int tag_alloc_policy;
+
         /*
          * Let the block layer assigns tags to all commands.
          */
diff --git a/include/scsi/scsi_tcq.h b/include/scsi/scsi_tcq.h
index 9708b28bd2aa..b27977e8aaed 100644
--- a/include/scsi/scsi_tcq.h
+++ b/include/scsi/scsi_tcq.h
@@ -66,7 +66,8 @@ static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
          * devices on the shared host (for libata)
          */
         if (!shost->bqt) {
-                shost->bqt = blk_init_tags(depth);
+                shost->bqt = blk_init_tags(depth,
+                        shost->hostt->tag_alloc_policy);
                 if (!shost->bqt)
                         return -ENOMEM;
         }