Merge branch 'for-4.15/block' of git://git.kernel.dk/linux-block

Pull core block layer updates from Jens Axboe:
 "This is the main pull request for block storage for 4.15-rc1.

  Nothing out of the ordinary in here, and no API changes or anything
  like that. Just various new features for drivers, core changes, etc.
  In particular, this pull request contains:

   - A patch series from Bart, closing the whole on blk/scsi-mq queue
     quescing.

   - A series from Christoph, building towards hidden gendisks (for
     multipath) and ability to move bio chains around.

   - NVMe
        - Support for native multipath for NVMe (Christoph).
        - Userspace notifications for AENs (Keith).
        - Command side-effects support (Keith).
        - SGL support (Chaitanya Kulkarni)
        - FC fixes and improvements (James Smart)
        - Lots of fixes and tweaks (Various)

   - bcache
        - New maintainer (Michael Lyle)
        - Writeback control improvements (Michael)
        - Various fixes (Coly, Elena, Eric, Liang, et al)

   - lightnvm updates, mostly centered around the pblk interface
     (Javier, Hans, and Rakesh).

   - Removal of unused bio/bvec kmap atomic interfaces (me, Christoph)

   - Writeback series that fix the much discussed hundreds of millions
     of sync-all units. This goes all the way, as discussed previously
     (me).

   - Fix for missing wakeup on writeback timer adjustments (Yafang
     Shao).

   - Fix laptop mode on blk-mq (me).

   - {mq,name} tupple lookup for IO schedulers, allowing us to have
     alias names. This means you can use 'deadline' on both !mq and on
     mq (where it's called mq-deadline). (me).

   - blktrace race fix, oopsing on sg load (me).

   - blk-mq optimizations (me).

   - Obscure waitqueue race fix for kyber (Omar).

   - NBD fixes (Josef).

   - Disable writeback throttling by default on bfq, like we do on cfq
     (Luca Miccio).

   - Series from Ming that enable us to treat flush requests on blk-mq
     like any other request. This is a really nice cleanup.

   - Series from Ming that improves merging on blk-mq with schedulers,
     getting us closer to flipping the switch on scsi-mq again.

   - BFQ updates (Paolo).

   - blk-mq atomic flags memory ordering fixes (Peter Z).

   - Loop cgroup support (Shaohua).

   - Lots of minor fixes from lots of different folks, both for core and
     driver code"

* 'for-4.15/block' of git://git.kernel.dk/linux-block: (294 commits)
  nvme: fix visibility of "uuid" ns attribute
  blk-mq: fixup some comment typos and lengths
  ide: ide-atapi: fix compile error with defining macro DEBUG
  blk-mq: improve tag waiting setup for non-shared tags
  brd: remove unused brd_mutex
  blk-mq: only run the hardware queue if IO is pending
  block: avoid null pointer dereference on null disk
  fs: guard_bio_eod() needs to consider partitions
  xtensa/simdisk: fix compile error
  nvme: expose subsys attribute to sysfs
  nvme: create 'slaves' and 'holders' entries for hidden controllers
  block: create 'slaves' and 'holders' entries for hidden gendisks
  nvme: also expose the namespace identification sysfs files for mpath nodes
  nvme: implement multipath access to nvme subsystems
  nvme: track shared namespaces
  nvme: introduce a nvme_ns_ids structure
  nvme: track subsystems
  block, nvme: Introduce blk_mq_req_flags_t
  block, scsi: Make SCSI quiesce and resume work reliably
  block: Add the QUEUE_FLAG_PREEMPT_ONLY request queue flag
  ...

3 files changed, 19 insertions, 16 deletions

diff --git a/Documentation/ABI/obsolete/proc-sys-vm-nr_pdflush_threads b/Documentation/ABI/obsolete/proc-sys-vm-nr_pdflush_threads
deleted file mode 100644
index b0b0eeb20fe3..000000000000
--- a/Documentation/ABI/obsolete/proc-sys-vm-nr_pdflush_threads
+++ /dev/null
@@ -1,5 +0,0 @@
-What:		/proc/sys/vm/nr_pdflush_threads
-Date:		June 2012
-Contact:	Wanpeng Li <liwp@linux.vnet.ibm.com>
-Description: Since pdflush is replaced by per-BDI flusher, the interface of old pdflush
-             exported in /proc/sys/vm/ should be removed.
diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt
index 9490f2845f06..86927029a52d 100644
--- a/Documentation/block/biodoc.txt
+++ b/Documentation/block/biodoc.txt
@@ -216,10 +216,9 @@ may need to abort DMA operations and revert to PIO for the transfer, in
 which case a virtual mapping of the page is required. For SCSI it is also
 done in some scenarios where the low level driver cannot be trusted to
 handle a single sg entry correctly. The driver is expected to perform the
-kmaps as needed on such occasions using the __bio_kmap_atomic and bio_kmap_irq
-routines as appropriate. A driver could also use the blk_queue_bounce()
-routine on its own to bounce highmem i/o to low memory for specific requests
-if so desired.
+kmaps as needed on such occasions as appropriate. A driver could also use
+the blk_queue_bounce() routine on its own to bounce highmem i/o to low
+memory for specific requests if so desired.
 
 iii. The i/o scheduler algorithm itself can be replaced/set as appropriate
 
@@ -1137,8 +1136,8 @@ use dma_map_sg for scatter gather) to be able to ship it to the driver. For
 PIO drivers (or drivers that need to revert to PIO transfer once in a
 while (IDE for example)), where the CPU is doing the actual data
 transfer a virtual mapping is needed. If the driver supports highmem I/O,
-(Sec 1.1, (ii) ) it needs to use __bio_kmap_atomic and bio_kmap_irq to
-temporarily map a bio into the virtual address space.
+(Sec 1.1, (ii) ) it needs to use kmap_atomic or similar to temporarily map
+a bio into the virtual address space.
 
 
 8. Prior/Related/Impacted patches
diff --git a/Documentation/block/null_blk.txt b/Documentation/block/null_blk.txt
index 3140dbd860d8..733927a7b501 100644
--- a/Documentation/block/null_blk.txt
+++ b/Documentation/block/null_blk.txt
@@ -38,7 +38,7 @@ gb=[Size in GB]: Default: 250GB
 bs=[Block size (in bytes)]: Default: 512 bytes
   The block size reported to the system.
 
-nr_devices=[Number of devices]: Default: 2
+nr_devices=[Number of devices]: Default: 1
   Number of block devices instantiated. They are instantiated as /dev/nullb0,
   etc.
 
@@ -52,13 +52,13 @@ irqmode=[0-2]: Default: 1-Soft-irq
   2: Timer: Waits a specific period (completion_nsec) for each IO before
      completion.
 
-completion_nsec=[ns]: Default: 10.000ns
+completion_nsec=[ns]: Default: 10,000ns
   Combined with irqmode=2 (timer). The time each completion event must wait.
 
-submit_queues=[0..nr_cpus]:
+submit_queues=[1..nr_cpus]:
   The number of submission queues attached to the device driver. If unset, it
-  defaults to 1 on single-queue and bio-based instances. For multi-queue,
-  it is ignored when use_per_node_hctx module parameter is 1.
+  defaults to 1. For multi-queue, it is ignored when use_per_node_hctx module
+  parameter is 1.
 
 hw_queue_depth=[0..qdepth]: Default: 64
   The hardware queue depth of the device.
@@ -73,3 +73,12 @@ use_per_node_hctx=[0/1]: Default: 0
 
 use_lightnvm=[0/1]: Default: 0
   Register device with LightNVM. Requires blk-mq and CONFIG_NVM to be enabled.
+
+no_sched=[0/1]: Default: 0
+  0: nullb* use default blk-mq io scheduler.
+  1: nullb* doesn't use io scheduler.
+
+shared_tags=[0/1]: Default: 0
+  0: Tag set is not shared.
+  1: Tag set shared between devices for blk-mq. Only makes sense with
+     nr_devices > 1, otherwise there's no tag set to share.