Now that we converted everything to the newer block write cache
interface, kill off the queue flush_flags and queueable flush
entries.
Signed-off-by: Jens Axboe <axboe@fb.com>

This patch adds a check on nvme_watchdog_timer() function to avoid the
call to reset_work() when an error recovery process is ongoing on
controller. The check is made by looking at pci_channel_offline()
result.

If we don't check for this on nvme_watchdog_timer(), error recovery
mechanism can't recover well, because reset_work() won't be able to
do its job (since we're in the middle of an error) and so the
controller is removed from the system before error recovery mechanism
can perform slot reset (which would allow the adapter to recover).

In this patch we also have split the huge condition expression on
nvme_watchdog_timer() by introducing an auxiliary function to help
make the code more readable.
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Depending on options, we might not be using dev in nvme_cancel_io():

drivers/nvme/host/pci.c: In function ‘nvme_cancel_io’:
drivers/nvme/host/pci.c:970:19: warning: unused variable ‘dev’ [-Wunused-variable]
  struct nvme_dev *dev = data;
                   ^

So get rid of it, and just cast for the dev_dbg_ratelimited() call.

Fixes: 82b4552b ("nvme: Use blk-mq helper for IO termination")
Signed-off-by: Jens Axboe <axboe@fb.com>

We don't have any drivers left using it, so kill it off. Update
documentation to use the newer blk_queue_write_cache().
Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

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

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

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

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

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

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

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

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

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

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

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

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

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

The driver calls it with 0 for flags, since it doesn't have a writeback
cache. Just remove the call, as it's a no-op right now.
Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

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

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

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

Switch to the newer interface, instead of using blk_queue_flush()
directly.
Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>

Add an internal helper and flag for setting whether a queue has
write back caching, or write through (or none). Add a sysfs file
to show this as well, and make it changeable from user space.

This will replace the (awkward) blk_queue_flush() interface that
drivers currently use to inform the block layer of write cache state
and capabilities.
Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

No caller outside the blk-mq code so we can settle
with it static.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

Only a single tags array anyway.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

blk-mq offers a tagset iterator so let's use that
instead of using nvme_clear_queues.

Note, we changed nvme_queue_cancel_ios name to nvme_cancel_io
as there is no concept of a queue now in this function (we
also lost the print).
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

If the controller is degraded, the driver should stay out of the way so
the user can recover the drive. This patch skips driver initiated async
event requests when the drive is in this state.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

This moves nvme_setup_{flush,discard,rw} calls into a common
nvme_setup_cmd() helper. So we can eventually hide all the command
setup in the core module and don't even need to update the fabrics
drivers for any specific command type.
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

This rewrites nvme_setup_discard() with blk_add_request_payload().
It allocates only the necessary amount(16 bytes) for the payload.
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

The helper returns the number of bytes that need to be mapped
using PRPs/SGL entries.
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

When unloading driver, nvme_disable_io_queues() calls nvme_delete_queue()
that sends nvme_admin_delete_cq command to admin sq. So when the command
completed, the lock acquired by nvme_irq() actually belongs to admin queue.

While the lock that nvme_del_cq_end() trying to acquire belongs to io queue.
So it will not deadlock.

This patch adds lock nesting notation to fix following report.

[  109.840952] =============================================
[  109.846379] [ INFO: possible recursive locking detected ]
[  109.851806] 4.5.0+ #180 Tainted: G            E
[  109.856533] ---------------------------------------------
[  109.861958] swapper/0/0 is trying to acquire lock:
[  109.866771]  (&(&nvmeq->q_lock)->rlock){-.....}, at: [<ffffffffc0820bc6>] nvme_del_cq_end+0x26/0x70 [nvme]
[  109.876535]
[  109.876535] but task is already holding lock:
[  109.882398]  (&(&nvmeq->q_lock)->rlock){-.....}, at: [<ffffffffc0820c2b>] nvme_irq+0x1b/0x50 [nvme]
[  109.891547]
[  109.891547] other info that might help us debug this:
[  109.898107]  Possible unsafe locking scenario:
[  109.898107]
[  109.904056]        CPU0
[  109.906515]        ----
[  109.908974]   lock(&(&nvmeq->q_lock)->rlock);
[  109.913381]   lock(&(&nvmeq->q_lock)->rlock);
[  109.917787]
[  109.917787]  *** DEADLOCK ***
[  109.917787]
[  109.923738]  May be due to missing lock nesting notation
[  109.923738]
[  109.930558] 1 lock held by swapper/0/0:
[  109.934413]  #0:  (&(&nvmeq->q_lock)->rlock){-.....}, at: [<ffffffffc0820c2b>] nvme_irq+0x1b/0x50 [nvme]
[  109.944010]
[  109.944010] stack backtrace:
[  109.948389] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G            E   4.5.0+ #180
[  109.955734] Hardware name: Dell Inc. OptiPlex 7010/0YXT71, BIOS A15 08/12/2013
[  109.962989]  0000000000000000 ffff88011e203c38 ffffffff81383d9c ffffffff81c13540
[  109.970478]  ffffffff826711d0 ffff88011e203ce8 ffffffff810bb429 0000000000000046
[  109.977964]  0000000000000046 0000000000000000 0000000000b2e597 ffffffff81f4cb00
[  109.985453] Call Trace:
[  109.987911]  <IRQ>  [<ffffffff81383d9c>] dump_stack+0x85/0xc9
[  109.993711]  [<ffffffff810bb429>] __lock_acquire+0x19b9/0x1c60
[  109.999575]  [<ffffffff810b6d1d>] ? trace_hardirqs_off+0xd/0x10
[  110.005524]  [<ffffffff810b386d>] ? complete+0x3d/0x50
[  110.010688]  [<ffffffff810bb760>] lock_acquire+0x90/0xf0
[  110.016029]  [<ffffffffc0820bc6>] ? nvme_del_cq_end+0x26/0x70 [nvme]
[  110.022418]  [<ffffffff81772afb>] _raw_spin_lock_irqsave+0x4b/0x60
[  110.028632]  [<ffffffffc0820bc6>] ? nvme_del_cq_end+0x26/0x70 [nvme]
[  110.035019]  [<ffffffffc0820bc6>] nvme_del_cq_end+0x26/0x70 [nvme]
[  110.041232]  [<ffffffff8135b485>] blk_mq_end_request+0x35/0x60
[  110.047095]  [<ffffffffc0821ad8>] nvme_complete_rq+0x68/0x190 [nvme]
[  110.053481]  [<ffffffff8135b53f>] __blk_mq_complete_request+0x8f/0x130
[  110.060043]  [<ffffffff8135b611>] blk_mq_complete_request+0x31/0x40
[  110.066343]  [<ffffffffc08209e3>] __nvme_process_cq+0x83/0x240 [nvme]
[  110.072818]  [<ffffffffc0820c35>] nvme_irq+0x25/0x50 [nvme]
[  110.078419]  [<ffffffff810cdb66>] handle_irq_event_percpu+0x36/0x110
[  110.084804]  [<ffffffff810cdc77>] handle_irq_event+0x37/0x60
[  110.090491]  [<ffffffff810d0ea3>] handle_edge_irq+0x93/0x150
[  110.096180]  [<ffffffff81012306>] handle_irq+0xa6/0x130
[  110.101431]  [<ffffffff81011abe>] do_IRQ+0x5e/0x120
[  110.106333]  [<ffffffff8177384c>] common_interrupt+0x8c/0x8c
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@fb.com>

Multiple users have reported device initialization failure due the driver
not receiving legacy PCI interrupts. This is not unique to any particular
controller, but has been observed on multiple platforms.

There have been no issues reported or observed when with message signaled
interrupts, so this patch attempts to use MSI-x during initialization,
falling back to MSI. If that fails, legacy would become the default.

The setup_io_queues error handling had to change as a result: the admin
queue's msix_entry used to be initialized to the legacy IRQ. The case
where nr_io_queues is 0 would fail request_irq when setting up the admin
queue's interrupt since re-enabling MSI-x fails with 0 vectors, leaving
the admin queue's msix_entry invalid. Instead, return success immediately.
Reported-by: Tim Muhlemmer <muhlemmer@gmail.com>
Reported-by: Jon Derrick <jonathan.derrick@intel.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

Its useful to iterate on all the active tags in cases
where we will need to fail all the queues IO.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
[hch: carefully check for valid tagsets]
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

We could kmalloc() the payload, so need the offset in page.
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

Commit 947e9762 ("writeback: update wb_over_bg_thresh() to use
wb_domain aware operations") unintentionally changed this function's
meaning from "are there more dirty pages than the background writeback
threshold" to "are there more dirty pages than the writeback threshold".
The background writeback threshold is typically half of the writeback
threshold, so this had the effect of raising the number of dirty pages
required to cause a writeback worker to perform background writeout.

This can cause a very severe performance regression when a BDI uses
BDI_CAP_STRICTLIMIT because balance_dirty_pages() and the writeback worker
can now disagree on whether writeback should be initiated.

For example, in a system having 1GB of RAM, a single spinning disk, and
a "pass-through" FUSE filesystem mounted over the disk, application code
mmapped a 128MB file on the disk and was randomly dirtying pages in that
mapping.

Because FUSE uses strictlimit and has a default max_ratio of only 1%,
in balance_dirty_pages, thresh is ~200, bg_thresh is ~100, and the
dirty_freerun_ceiling is the average of those, ~150. So, it pauses the
dirtying processes when we have 151 dirty pages and wakes up a
background writeback worker. But the worker tests the wrong threshold
(200 instead of 100), so it does not initiate writeback and just
returns.

Thus, balance_dirty_pages keeps looping, sleeping and then waking up the
worker who will do nothing. It remains stuck in this state until the few
dirty pages that we have finally expire and we write them back for that
reason. Then the whole process repeats, resulting in near-zero
throughput through the FUSE BDI.

The fix is to call the parameterized variant of wb_calc_thresh, so that
the worker will do writeback if the bg_thresh is exceeded which was the
bahavior before the referenced commit.

Fixes: 947e9762 ("writeback: update wb_over_bg_thresh() to use
                     wb_domain aware operations")
Signed-off-by: Howard Cochran <hcochran@kernelspring.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>

Pull ARM fixes from Russell King:
 "A couple of small fixes, and wiring up the new syscalls which appeared
  during the merge window"

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8550/1: protect idiv patching against undefined gcc behavior
  ARM: wire up preadv2 and pwritev2 syscalls
  ARM: SMP enable of cache maintanence broadcast

Pull MMC fixes from Ulf Hansson:
 "Here are a couple of mmc fixes intended for v4.6 rc3:

  MMC host:
   - sdhci: Fix regression setting power on Trats2 board
   - sdhci-pci: Add support and PCI IDs for more Broxton host controllers"

* tag 'mmc-v4.6-rc1' of git://git.linaro.org/people/ulf.hansson/mmc:
  mmc: sdhci-pci: Add support and PCI IDs for more Broxton host controllers
  mmc: sdhci: Fix regression setting power on Trats2 board

Pull i2c fixes from Wolfram Sang:
 "Some bugfixes from I2C:

   - fix a uevent triggered boot problem by removing a useless debug
     print

   - fix sysfs-attributes of the new i2c-demux-pinctrl driver to follow
     standard kernel behaviour

   - fix a potential division-by-zero error (needed two takes)"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: jz4780: really prevent potential division by zero
  Revert "i2c: jz4780: prevent potential division by zero"
  i2c: jz4780: prevent potential division by zero
  i2c: mux: demux-pinctrl: Update docs to new sysfs-attributes
  i2c: mux: demux-pinctrl: Clean up sysfs attributes
  i2c: prevent endless uevent loop with CONFIG_I2C_DEBUG_CORE