Merge branch 'for-3.20/core' of git://git.kernel.dk/linux-block

Pull core block IO changes from Jens Axboe:
 "This contains:

   - A series from Christoph that cleans up and refactors various parts
     of the REQ_BLOCK_PC handling.  Contributions in that series from
     Dongsu Park and Kent Overstreet as well.

   - CFQ:
        - A bug fix for cfq for realtime IO scheduling from Jeff Moyer.
        - A stable patch fixing a potential crash in CFQ in OOM
          situations.  From Konstantin Khlebnikov.

   - blk-mq:
        - Add support for tag allocation policies, from Shaohua. This is
          a prep patch enabling libata (and other SCSI parts) to use the
          blk-mq tagging, instead of rolling their own.
        - Various little tweaks from Keith and Mike, in preparation for
          DM blk-mq support.
        - Minor little fixes or tweaks from me.
        - A double free error fix from Tony Battersby.

   - The partition 4k issue fixes from Matthew and Boaz.

   - Add support for zero+unprovision for blkdev_issue_zeroout() from
     Martin"

* 'for-3.20/core' of git://git.kernel.dk/linux-block: (27 commits)
  block: remove unused function blk_bio_map_sg
  block: handle the null_mapped flag correctly in blk_rq_map_user_iov
  blk-mq: fix double-free in error path
  block: prevent request-to-request merging with gaps if not allowed
  blk-mq: make blk_mq_run_queues() static
  dm: fix multipath regression due to initializing wrong request
  cfq-iosched: handle failure of cfq group allocation
  block: Quiesce zeroout wrapper
  block: rewrite and split __bio_copy_iov()
  block: merge __bio_map_user_iov into bio_map_user_iov
  block: merge __bio_map_kern into bio_map_kern
  block: pass iov_iter to the BLOCK_PC mapping functions
  block: add a helper to free bio bounce buffer pages
  block: use blk_rq_map_user_iov to implement blk_rq_map_user
  block: simplify bio_map_kern
  block: mark blk-mq devices as stackable
  block: keep established cmd_flags when cloning into a blk-mq request
  block: add blk-mq support to blk_insert_cloned_request()
  block: require blk_rq_prep_clone() be given an initialized clone request
  blk-mq: add tag allocation policy
  ...

2 files changed, 5 insertions, 1 deletions

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;
         }