Merge branches 'for-5.1/upstream-fixes', 'for-5.2/core', 'for-5.2/ish', 'for-5.2/logitech', 'for-5.2/macally', 'for-5.2/picolcd', 'for-5.2/sensor' and 'for-5.2/u2fzero' into for-linus

dm snapshot: Use fine-grained locking scheme

Substitute the global locking scheme with a fine grained one, employing
the read-write semaphore and the scalable exception tables with
per-bucket locks

dm snapshot: Use fine-grained locking scheme

Substitute the global locking scheme with a fine grained one, employing
the read-write semaphore and the scalable exception tables with
per-bucket locks introduced by the previous two commits.

Summarizing, we now use a read-write semaphore to protect the mostly
read fields of the snapshot structure, e.g., valid, active, etc., and
per-bucket bit spinlocks to protect accesses to the complete and pending
exception tables.

Finally, we use an extra spinlock (pe_allocation_lock) to serialize the
allocation of new exceptions by the exception store. This allocation is
really fast, so the extra spinlock doesn't hurt the performance.

This scheme allows dm-snapshot to scale better, resulting in increased
IOPS and reduced latency.

Following are some benchmark results using the null_blk device:

modprobe null_blk gb=1024 bs=512 submit_queues=8 hw_queue_depth=4096 \
queue_mode=2 irqmode=1 completion_nsec=1 nr_devices=1

* Benchmark fio_origin_randwrite_throughput_N, from the device mapper
test suite [1] (direct IO, random 4K writes to origin device, IO
engine libaio):

+--------------+-------------+------------+
| # of workers | IOPS Before | IOPS After |
+--------------+-------------+------------+
| 1 | 57708 | 66421 |
| 2 | 63415 | 77589 |
| 4 | 67276 | 98839 |
| 8 | 60564 | 109258 |
+--------------+-------------+------------+

* Benchmark fio_origin_randwrite_latency_N, from the device mapper test
suite [1] (direct IO, random 4K writes to origin device, IO engine
psync):

+--------------+-----------------------+----------------------+
| # of workers | Latency (usec) Before | Latency (usec) After |
+--------------+-----------------------+----------------------+
| 1 | 16.25 | 13.27 |
| 2 | 31.65 | 25.08 |
| 4 | 55.28 | 41.08 |
| 8 | 121.47 | 74.44 |
+--------------+-----------------------+----------------------+

* Benchmark fio_snapshot_randwrite_throughput_N, from the device mapper
test suite [1] (direct IO, random 4K writes to snapshot device, IO
engine libaio):

+--------------+-------------+------------+
| # of workers | IOPS Before | IOPS After |
+--------------+-------------+------------+
| 1 | 72593 | 84938 |
| 2 | 97379 | 134973 |
| 4 | 90610 | 143077 |
| 8 | 90537 | 180085 |
+--------------+-------------+------------+

* Benchmark fio_snapshot_randwrite_latency_N, from the device mapper
test suite [1] (direct IO, random 4K writes to snapshot device, IO
engine psync):

+--------------+-----------------------+----------------------+
| # of workers | Latency (usec) Before | Latency (usec) After |
+--------------+-----------------------+----------------------+
| 1 | 12.53 | 10.6 |
| 2 | 19.78 | 14.89 |
| 4 | 40.37 | 23.47 |
| 8 | 89.32 | 48.48 |
+--------------+-----------------------+----------------------+

[1] https://github.com/jthornber/device-mapper-test-suite

Co-developed-by: Ilias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

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dm snapshot: Make exception tables scalable

Use list_bl to implement the exception hash tables' buckets. This change
permits concurrent access, to distinct buckets, by multiple threads.

Also, imple

dm snapshot: Make exception tables scalable

Use list_bl to implement the exception hash tables' buckets. This change
permits concurrent access, to distinct buckets, by multiple threads.

Also, implement helper functions to lock and unlock the exception tables
based on the chunk number of the exception at hand.

We retain the global locking, by means of down_write(), which is
replaced by the next commit.

Still, we must acquire the per-bucket spinlocks when accessing the hash
tables, since list_bl does not allow modification on unlocked lists.

Co-developed-by: Ilias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

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dm snapshot: Replace mutex with rw semaphore

dm-snapshot uses a single mutex to serialize every access to the
snapshot state. This includes all accesses to the complete and pending
exception tables,

dm snapshot: Replace mutex with rw semaphore

dm-snapshot uses a single mutex to serialize every access to the
snapshot state. This includes all accesses to the complete and pending
exception tables, which occur at every origin write, every snapshot
read/write and every exception completion.

The lock statistics indicate that this mutex is a bottleneck (average
wait time ~480 usecs for 8 processes doing random 4K writes to the
origin device) preventing dm-snapshot to scale as the number of threads
doing IO increases.

The major contention points are __origin_write()/snapshot_map() and
pending_complete(), i.e., the submission and completion of pending
exceptions.

Replace this mutex with a rw semaphore.

We essentially revert commit ae1093be5a0ef9 ("dm snapshot: use mutex
instead of rw_semaphore") and together with the next two patches we
substitute the single mutex with a fine-grained locking scheme, where we
use a read-write semaphore to protect the mostly read fields of the
snapshot structure, e.g., valid, active, etc., and per-bucket bit
spinlocks to protect accesses to the complete and pending exception
tables.

Co-developed-by: Ilias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

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dm snapshot: Don't sleep holding the snapshot lock

When completing a pending exception, pending_complete() waits for all
conflicting reads to drain, before inserting the final, completed
exception.

dm snapshot: Don't sleep holding the snapshot lock

When completing a pending exception, pending_complete() waits for all
conflicting reads to drain, before inserting the final, completed
exception. Conflicting reads are snapshot reads redirected to the
origin, because the relevant chunk is not remapped to the COW device the
moment we receive the read.

The completed exception must be inserted into the exception table after
all conflicting reads drain to ensure snapshot reads don't return
corrupted data. This is required because inserting the completed
exception into the exception table signals that the relevant chunk is
remapped and both origin writes and snapshot merging will now overwrite
the chunk in origin.

This wait is done holding the snapshot lock to ensure that
pending_complete() doesn't starve if new snapshot reads keep coming for
this chunk.

In preparation for the next commit, where we use a spinlock instead of a
mutex to protect the exception tables, we remove the need for holding
the lock while waiting for conflicting reads to drain.

We achieve this in two steps:

1. pending_complete() inserts the completed exception before waiting for
conflicting reads to drain and removes the pending exception after
all conflicting reads drain.

This ensures that new snapshot reads will be redirected to the COW
device, instead of the origin, and thus pending_complete() will not
starve. Moreover, we use the existence of both a completed and
a pending exception to signify that the COW is done but there are
conflicting reads in flight.

2. In __origin_write() we check first if there is a pending exception
and then if there is a completed exception. If there is a pending
exception any submitted BIO is delayed on the pe->origin_bios list and
DM_MAPIO_SUBMITTED is returned. This ensures that neither writes to the
origin nor snapshot merging can overwrite the origin chunk, until all
conflicting reads drain, and thus snapshot reads will not return
corrupted data.

Summarizing, we now have the following possible combinations of pending
and completed exceptions for a chunk, along with their meaning:

A. No exceptions exist: The chunk has not been remapped yet.
B. Only a pending exception exists: The chunk is currently being copied
to the COW device.
C. Both a pending and a completed exception exist: COW for this chunk
has completed but there are snapshot reads in flight which had been
redirected to the origin before the chunk was remapped.
D. Only the completed exception exists: COW has been completed and there
are no conflicting reads in flight.

Co-developed-by: Ilias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: Nikos Tsironis <ntsironis@arrikto.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

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Merge tag 'drm-intel-next-2019-04-04' into gvt-next

Merge back drm-intel-next for engine name definition refinement
and 54939ea0bd85 ("drm/i915: Switch to use HWS indices rather than addresses")
tha

Merge tag 'drm-intel-next-2019-04-04' into gvt-next

Merge back drm-intel-next for engine name definition refinement
and 54939ea0bd85 ("drm/i915: Switch to use HWS indices rather than addresses")
that would need gvt fixes to depend on.

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

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Merge drm/drm-next into drm-misc-next

Finally have a reason for a backmerge other than "it's been a while"!

Backmerging drm-next to -misc-next to facilitate Rob Herring's work on
Panfrost.

Signed-

Merge drm/drm-next into drm-misc-next

Finally have a reason for a backmerge other than "it's been a while"!

Backmerging drm-next to -misc-next to facilitate Rob Herring's work on
Panfrost.

Signed-off-by: Sean Paul <seanpaul@chromium.org>

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Merge tag 'v5.1-rc3' of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into fbdev-for-next

Linux 5.1-rc3

Sync with upstream (which now contains fbdev-v5.1 changes) to
prepare a base

Merge tag 'v5.1-rc3' of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into fbdev-for-next

Linux 5.1-rc3

Sync with upstream (which now contains fbdev-v5.1 changes) to
prepare a base for fbdev-v5.2 changes.

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Merge drm/drm-next into drm-intel-next-queued

This is needed to get the fourcc code merged without conflicts.

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

Merge tag 'v5.1-rc2' into next-general

Merge to Linux 5.1-rc2 for subsystems to work with.

Merge tag 'v5.1-rc1' into spi-5.2

Linux 5.1-rc1

Merge tag 'v5.1-rc1' into regulator-5.2

Linux 5.1-rc1

Merge tag 'v5.1-rc1' into asoc-5.2

Linux 5.1-rc1

Merge tag 'v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into mlx5-next

Linux 5.1-rc1

We forgot to reset the branch last merge window thus mlx5-next is outdated
and stil

Merge tag 'v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into mlx5-next

Linux 5.1-rc1

We forgot to reset the branch last merge window thus mlx5-next is outdated
and still based on 5.0-rc2. This merge commit is needed to sync mlx5-next
branch with 5.1-rc1.

Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

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Merge tag 'asoc-fix-v5.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v5.1

A few core fixes along with the driver specific ones, mainly fixing

Merge tag 'asoc-fix-v5.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Fixes for v5.1

A few core fixes along with the driver specific ones, mainly fixing
small issues that only affect x86 platforms for various reasons (their
unusual machine enumeration mechanisms mainly, plus a fix for error
handling in topology).

There's some of the driver fixes that look larger than they are, like
the hdmi-codec changes which resulted in an indentation change, and most
of the other large changes are for new drivers like the STM32 changes.

show more ...

Merge remote-tracking branch 'net/master'

Merge tag 'v5.1-rc1' into asoc-5.1

Linux 5.1-rc1

Merge tag 'for-5.1/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

- Update bio-based DM core to always call blk_q

Merge tag 'for-5.1/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

- Update bio-based DM core to always call blk_queue_split() and update
DM targets to properly advertise discard limits that
blk_queue_split() looks at when dtermining to split discard. Whereby
allowing DM core's own 'split_discard_bios' to be removed.

- Improve DM cache target to provide support for discard passdown to
the origin device.

- Introduce support to directly boot to a DM mapped device from init by
using dm-mod.create= module param. This eliminates the need for an
elaborate initramfs that is otherwise needed to create DM devices.

This feature's implementation has been worked on for quite some time
(got up to v12) and is of particular interest to Android and other
more embedded platforms (e.g. ARM).

- Rate limit errors from the DM integrity target that were identified
as the cause for recent NMI hangs due to console limitations.

- Add sanity checks for user input to thin-pool and external snapshot
creation.

- Remove some unused leftover kmem caches from when old .request_fn
request-based support was removed.

- Various small cleanups and fixes to targets (e.g. typos, needless
unlikely() annotations, use struct_size(), remove needless
.direct_access method from dm-snapshot)

* tag 'for-5.1/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm integrity: limit the rate of error messages
dm snapshot: don't define direct_access if we don't support it
dm cache: add support for discard passdown to the origin device
dm writecache: fix typo in name for writeback_wq
dm: add support to directly boot to a mapped device
dm thin: add sanity checks to thin-pool and external snapshot creation
dm block manager: remove redundant unlikely annotation
dm verity fec: remove redundant unlikely annotation
dm integrity: remove redundant unlikely annotation
dm: always call blk_queue_split() in dm_process_bio()
dm: fix to_sector() for 32bit
dm switch: use struct_size() in kzalloc()
dm: remove unused _rq_tio_cache and _rq_cache
dm: eliminate 'split_discard_bios' flag from DM target interface
dm: update dm_process_bio() to split bio if in ->make_request_fn()

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dm snapshot: don't define direct_access if we don't support it

Don't define a direct_access function that fails, dm_dax_direct_access
already fails with -EIO if the pointer is zero;

Signed-off-by:

dm snapshot: don't define direct_access if we don't support it

Don't define a direct_access function that fails, dm_dax_direct_access
already fails with -EIO if the pointer is zero;

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

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Merge tag 'v5.0-rc5' of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into fbdev-for-next

Linux 5.0-rc5

Sync with upstream (which now contains fbdev-v5.0-rc3 changes) to
prepare a

Merge tag 'v5.0-rc5' of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into fbdev-for-next

Linux 5.0-rc5

Sync with upstream (which now contains fbdev-v5.0-rc3 changes) to
prepare a base for fbdev-v5.1 changes.

show more ...

Merge tag 'v4.20' into for-linus

Sync with mainline to get linux/overflow.h among other things.

Merge tag 'v4.20' into next

Merge with mainline to bring in the new APIs.

Merge drm/drm-next into drm-misc-next

drm-next has been forwarded to 5.0-rc1, and we need it to apply the damage
helper for dirtyfb series from Noralf Trønnes.

Signed-off-by: Maxime Ripard <maxime.

Merge drm/drm-next into drm-misc-next

drm-next has been forwarded to 5.0-rc1, and we need it to apply the damage
helper for dirtyfb series from Noralf Trønnes.

Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>

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Merge tag 'v5.0-rc1' into next-general

Linux 5.0-rc1

Sync to pick up LSM stacking work (which is based on -rc1).

Merge drm/drm-next into drm-intel-next-queued

Generally catch up with 5.0-rc1, and specifically get the changes:

96d4f267e40f ("Remove 'type' argument from access_ok() function")
0b2c8f8b6b0c ("i91

Merge drm/drm-next into drm-intel-next-queued

Generally catch up with 5.0-rc1, and specifically get the changes:

96d4f267e40f ("Remove 'type' argument from access_ok() function")
0b2c8f8b6b0c ("i915: fix missing user_access_end() in page fault exception case")
594cc251fdd0 ("make 'user_access_begin()' do 'access_ok()'")

Signed-off-by: Jani Nikula <jani.nikula@intel.com>

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