Currently there's no way to enable wbt if it's not enabled in the
kernel config by default for a device. Allow a write to the
'wbt_lat_usec' queue sysfs file to enable wbt.

This is useful for both the kernel config case, but also if the
device is CFQ managed and it was turned off by default.
Signed-off-by: Jens Axboe <axboe@fb.com>

Make it clear that we are disabling wbt for the specified queued,
if it was enabled by default. This is in preparation for allowing
users to re-enable wbt, and not have it disabled automatically
again.
Signed-off-by: Jens Axboe <axboe@fb.com>

Allow a write of '-1' to reset the default latency target for
a given device. This removes knowledge of the different default
settings for rotational vs non-rotational from user space.
Signed-off-by: Jens Axboe <axboe@fb.com>

Multiple paths don't set it properly, ensure that we do.

Fixes: 9561a7ad ("nbd: add multi-connection support")
Signed-off-by: Jens Axboe <axboe@fb.com>

Bit #7 is already used, move to bit #8 which is the first unused
one.

Fixes: 9561a7ad ("nbd: add multi-connection support")
Signed-off-by: Jens Axboe <axboe@fb.com>

NBD can become contended on its single connection.  We have to serialize all
writes and we can only process one read response at a time.  Fix this by
allowing userspace to provide multiple connections to a single nbd device.  This
coupled with block-mq drastically increases performance in multi-process cases.
Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

blkcg allocates some per-cgroup data structures with GFP_NOWAIT and
when that fails falls back to operations which aren't specific to the
cgroup.  Occassional failures are expected under pressure and falling
back to non-cgroup operation is the right thing to do.

Unfortunately, I forgot to add __GFP_NOWARN to these allocations and
these expected failures end up creating a lot of noise.  Add
__GFP_NOWARN.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Marc MERLIN <marc@merlins.org>
Reported-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>

The check on bio->bi_vcnt doesn't make sense in erase_end_io().
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Also code gets simplified a bit.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Also this patch simplify the code a bit.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Always bio_add_page() is the standard and preferred way to
do the task.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Instead we use standard iterator way to do that.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

When the bio is full, bio_add_pc_page() will return zero,
so use this information tell when the bio is full.

Also replace access to .bi_vcnt for pr_debug() with bio_segments().
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@fb.com>

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

For a non-cloned bio, bio_add_page() only returns failure when
the io vec table is full, but in that case, bio->bi_vcnt can't
be zero at all.

So remove the impossible failure handling.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Some drivers often use external bvec table, so introduce
this helper for this case. It is always safe to access the
bio->bi_io_vec in this way for this case.

After converting to this usage, it will becomes a bit easier
to evaluate the remaining direct access to bio->bi_io_vec,
so it can help to prepare for the following multipage bvec
support.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Fixed up the new O_DIRECT cases.
Signed-off-by: Jens Axboe <axboe@fb.com>

We store the bits in the bdev sector size locally, but we don't use
the calculation anymore. All we do with it is shift it back up to
the bdev sector size. So let's just use that directly and kill the
variable and bits calculation.
Signed-off-by: Jens Axboe <axboe@fb.com>

A direct I/O alignment must be always checked against the device blocks size,
but the I/O offset (bio->bi_iter.bi_sector must always use 512B sector unit, and
not the actual logical block size.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

If a ZBC device is partitioned and operations are performed on the partition
the zone information is rebased to the partition, however the zone reset
is not mapped from the partition to device as are other operations.

This causes the API (report zones / reset zone) to be unbalanced in this
regard. Checking for the zone reset op code explicitly will balance the
API.
Signed-off-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Since commit 87374179 ("block: add a proper block layer data direction
encoding") we only or the new op and flags into bi_opf in bio_set_op_attrs
instead of clearing the old value.  I've not seen any breakage with the
new behavior, but it seems dangerous.

Also convert it to an inline function to make the argument passing
safer.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

This driver is both orphaned, and not really useful anymore. Mark
it as such, and remove it in a future kernel after a release or
two.
Signed-off-by: Jens Axboe <axboe@fb.com>

With compilers which follow the C99 standard (like modern versions of
gcc and clang), "extern inline" does the opposite thing from older
versions of gcc (emits code for an externally linkable version of the
inline function).

"static inline" does the intended behavior in all cases instead.

Description taken from commit 6d91857d ("staging, rtl8192e,
LLVMLinux: Change extern inline to static inline").

This also fixes the following GCC warning when building with CONFIG_PM
disabled:

  ./include/linux/blkdev.h:1143:20: warning: no previous prototype for 'blk_set_runtime_active' [-Wmissing-prototypes]

Fixes: d07ab6d1 ("block: Add blk_set_runtime_active()")
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Jens Axboe <axboe@fb.com>

Drop duplicate header scatterlist.h from skd_main.c.
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

This was documented in the original commit, 64f1c21e, but it
never made it into the proper location for queue sysfs files.
Signed-off-by: Jens Axboe <axboe@fb.com>

Similar to the simple fast path, but we now need a dio structure to
track multiple-bio completions.  It's basically a cut-down version
of the new iomap-based direct I/O code for filesystems, but without
all the logic to call into the filesystem for extent lookup or
allocation, and without the complex I/O completion workqueue handler
for AIO - instead we just use the FUA bit on the bios to ensure
data is flushed to stable storage.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

Split the op setting code into a helper, use it in both places.
Signed-off-by: Jens Axboe <axboe@fb.com>

Just alloc the bio_vec array if we exceed the inline limit.
Signed-off-by: Jens Axboe <axboe@fb.com>

The previous commit introduced the hybrid sleep/poll mode. Take
that one step further, and use the completion latencies to
automatically sleep for half the mean completion time. This is
a good approximation.

This changes the 'io_poll_delay' sysfs file a bit to expose the
various options. Depending on the value, the polling code will
behave differently:

-1	Never enter hybrid sleep mode
 0	Use half of the completion mean for the sleep delay
>0	Use this specific value as the sleep delay
Signed-off-by: Jens Axboe <axboe@fb.com>
Tested-By: Stephen Bates <sbates@raithlin.com>
Reviewed-By: Stephen Bates <sbates@raithlin.com>

This patch enables a hybrid polling mode. Instead of polling after IO
submission, we can induce an artificial delay, and then poll after that.
For example, if the IO is presumed to complete in 8 usecs from now, we
can sleep for 4 usecs, wake up, and then do our polling. This still puts
a sleep/wakeup cycle in the IO path, but instead of the wakeup happening
after the IO has completed, it'll happen before. With this hybrid
scheme, we can achieve big latency reductions while still using the same
(or less) amount of CPU.
Signed-off-by: Jens Axboe <axboe@fb.com>
Tested-By: Stephen Bates <sbates@raithlin.com>
Reviewed-By: Stephen Bates <sbates@raithlin.com>

This patch adds a small and simple fast patch for small direct I/O
requests on block devices that don't use AIO.  Between the neat
bio_iov_iter_get_pages helper that avoids allocating a page array
for get_user_pages and the on-stack bio and biovec this avoid memory
allocations and atomic operations entirely in the direct I/O code
(lower levels might still do memory allocations and will usually
have at least some atomic operations, though).
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Tested-By: Stephen Bates <sbates@raithlin.com>
Reviewed-By: Stephen Bates <sbates@raithlin.com>

For writes, we can get a completion in while we're still iterating
the request and bio chain. If that happens, we're reading freed
memory and we can crash.

Break out after the last segment and avoid having the iterator
read freed memory.
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

The newly added driver causes a harmless warning in some configurations:

block/blk-wbt.c:250:1: error: ‘inline’ is not at beginning of declaration [-Werror=old-style-declaration]
 static bool inline stat_sample_valid(struct blk_rq_stat *stat)

This makes it use the expected format for the declaration.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

If CONFIG_NVM is disabled, loading null_block module with use_lightnvm=1
fails. But there are no messages and documents related to the failure.

Add the appropriate error message.
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>

Massaged the text a bit.
Signed-off-by: Jens Axboe <axboe@fb.com>

In both legacy and mq path, req count of plug list is computed
before allocating request, so the number can be stale when falling
back to slept allocation, also the new introduced wbt can sleep
too.

This patch deals with the case by checking if plug list becomes
empty, and fixes the KASAN report of 'BUG: KASAN: stack-out-of-bounds'
which is introduced by Shaohua's patches of dispatching big request.

Fixes: 600271d9(blk-mq: immediately dispatch big size request)
Fixes: 50d24c34(block: immediately dispatch big size request)
Cc: Shaohua Li <shli@fb.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Let's not depend on any of the BLK_MQ_RQ_QUEUE_* constants having
specific values. No functional change.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Let's not depend on any of the BLK_MQ_RQ_QUEUE_* constants having
specific values. No functional change.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

->queue_rq() should return one of the BLK_MQ_RQ_QUEUE_* constants, not
an errno.

f4aa4c7b ("block: loop: convert to per-device workqueue")
Signed-off-by: Omar Sandoval <osandov@fb.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>

Normally, sd_read_capacity sets sdp->use_16_for_rw to 1 based on the
disk capacity so that READ16/WRITE16 are used for large drives.
However, for a zoned disk with RC_BASIS set to 0, the capacity reported
through READ_CAPACITY may be very small, leading to use_16_for_rw not being
set and READ10/WRITE10 commands being used, even after the actual zoned disk
capacity is corrected in sd_zbc_read_zones. This causes LBA offset overflow for
accesses beyond 2TB.

As the ZBC standard makes it mandatory for ZBC drives to support
the READ16/WRITE16 commands anyway, make sure that use_16_for_rw is set.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
eviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

Avoid that sparse complains about unbalanced lock actions.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Since we have proper enums for the stats directions, use them.
Signed-off-by: Jens Axboe <axboe@fb.com>