linux.git/drivers/dax/bus.c, branch v6.0

Merge branch 'akpm' (patches from Andrew)

2022-01-15T18:37:06+00:00

Merge misc updates from Andrew Morton:
 "146 patches.

  Subsystems affected by this patch series: kthread, ia64, scripts,
  ntfs, squashfs, ocfs2, vfs, and mm (slab-generic, slab, kmemleak,
  dax, kasan, debug, pagecache, gup, shmem, frontswap, memremap,
  memcg, selftests, pagemap, dma, vmalloc, memory-failure, hugetlb,
  userfaultfd, vmscan, mempolicy, oom-kill, hugetlbfs, migration, thp,
  ksm, page-poison, percpu, rmap, zswap, zram, cleanups, hmm, and
  damon)"

* emailed patches from Andrew Morton : (146 commits)
  mm/damon: hide kernel pointer from tracepoint event
  mm/damon/vaddr: hide kernel pointer from damon_va_three_regions() failure log
  mm/damon/vaddr: use pr_debug() for damon_va_three_regions() failure logging
  mm/damon/dbgfs: remove an unnecessary variable
  mm/damon: move the implementation of damon_insert_region to damon.h
  mm/damon: add access checking for hugetlb pages
  Docs/admin-guide/mm/damon/usage: update for schemes statistics
  mm/damon/dbgfs: support all DAMOS stats
  Docs/admin-guide/mm/damon/reclaim: document statistics parameters
  mm/damon/reclaim: provide reclamation statistics
  mm/damon/schemes: account how many times quota limit has exceeded
  mm/damon/schemes: account scheme actions that successfully applied
  mm/damon: remove a mistakenly added comment for a future feature
  Docs/admin-guide/mm/damon/usage: update for kdamond_pid and (mk|rm)_contexts
  Docs/admin-guide/mm/damon/usage: mention tracepoint at the beginning
  Docs/admin-guide/mm/damon/usage: remove redundant information
  Docs/admin-guide/mm/damon/usage: update for scheme quotas and watermarks
  mm/damon: convert macro functions to static inline functions
  mm/damon: modify damon_rand() macro to static inline function
  mm/damon: move damon_rand() definition into damon.h
  ...

device-dax: ensure dev_dax->pgmap is valid for dynamic devices

2022-01-15T14:30:25+00:00

Right now, only static dax regions have a valid @pgmap pointer in its
struct dev_dax.  Dynamic dax case however, do not.

In preparation for device-dax compound devmap support, make sure that
dev_dax pgmap field is set after it has been allocated and initialized.

dynamic dax device have the @pgmap is allocated at probe() and it's
managed by devm (contrast to static dax region which a pgmap is provided
and dax core kfrees it).  So in addition to ensure a valid @pgmap, clear
the pgmap when the dynamic dax device is released to avoid the same
pgmap ranges to be re-requested across multiple region device reconfigs.

Add a static_dev_dax() and use that helper in dev_dax_probe() to ensure
the initialization differences between dynamic and static regions are
more explicit.  While at it, consolidate the ranges initialization when
we allocate the @pgmap for the dynamic dax region case.  Also take the
opportunity to document the differences between static and dynamic da
regions.

Link: https://lkml.kernel.org/r/20211202204422.26777-8-joao.m.martins@oracle.com
Suggested-by: Dan Williams 
Signed-off-by: Joao Martins 
Cc: Christoph Hellwig 
Cc: Dave Jiang 
Cc: Jane Chu 
Cc: Jason Gunthorpe 
Cc: Jason Gunthorpe 
Cc: John Hubbard 
Cc: Jonathan Corbet 
Cc: Matthew Wilcox (Oracle) 
Cc: Mike Kravetz 
Cc: Muchun Song 
Cc: Naoya Horiguchi 
Cc: Vishal Verma 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

dax: remove the copy_from_iter and copy_to_iter methods

2021-12-18T16:04:53+00:00

These methods indirect the actual DAX read/write path.  In the end pmem
uses magic flush and mc safe variants and fuse and dcssblk use plain ones
while device mapper picks redirects to the underlying device.

Add set_dax_nocache() and set_dax_nomc() APIs to control which copy
routines are used to remove indirect call from the read/write fast path
as well as a lot of boilerplate code.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Vivek Goyal  [virtiofs]
Link: https://lore.kernel.org/r/20211215084508.435401-5-hch@lst.de
Signed-off-by: Dan Williams

dax: remove the DAXDEV_F_SYNC flag

2021-12-18T16:04:52+00:00

Remove the DAXDEV_F_SYNC flag and thus the flags argument to alloc_dax and
just let the drivers call set_dax_synchronous directly.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Pankaj Gupta 
Reviewed-by: Dan Williams 
Link: https://lore.kernel.org/r/20211215084508.435401-4-hch@lst.de
Signed-off-by: Dan Williams

dax: simplify the dax_device <-> gendisk association

2021-12-04T16:58:51+00:00

Replace the dax_host_hash with an xarray indexed by the pointer value
of the gendisk, and require explicitly calls from the block drivers that
want to associate their gendisk with a dax_device.

Signed-off-by: Christoph Hellwig 
Acked-by: Mike Snitzer 
Reviewed-by: Darrick J. Wong 
Link: https://lore.kernel.org/r/20211129102203.2243509-5-hch@lst.de
Signed-off-by: Dan Williams

dax: Kill DEV_DAX_PMEM_COMPAT

2021-11-25T03:21:35+00:00

The /sys/class/dax compatibility option has shipped in the kernel for 4
years now which should be sufficient time for tools to abandon the old
ABI in favor of the /sys/bus/dax device-model. Delete it now and see if
anyone screams.

Since this compatibility option shipped there has been more reports of
users being surprised by the compat ABI than surprised by the "new", so
the compat infrastructure has outlived its usefulness. Recall that
/sys/bus/dax device-model is required for the dax kmem driver which
allows PMEM to be used as "System RAM".

The following projects were known to have a dependency on /sys/class/dax
and have dropped their dependency as of the listed version:

- ndctl (including libndctl, daxctl, and libdaxctl): v64+
- fio: v3.13+
- pmdk: v1.5.2+

As further evidence this option is no longer needed some distributions
have already stopped enabling CONFIG_DEV_DAX_PMEM_COMPAT.

Cc: Ira Weiny 
Cc: Dave Jiang 
Reported-by: Vishal Verma 
Acked-by: Dave Hansen 
Reviewed-by: Jane Chu 
Link: https://lore.kernel.org/r/163701116195.3784476.726128179293466337.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams

bus: Make remove callback return void

2021-07-21T09:53:42+00:00

The driver core ignores the return value of this callback because there
is only little it can do when a device disappears.

This is the final bit of a long lasting cleanup quest where several
buses were converted to also return void from their remove callback.
Additionally some resource leaks were fixed that were caused by drivers
returning an error code in the expectation that the driver won't go
away.

With struct bus_type::remove returning void it's prevented that newly
implemented buses return an ignored error code and so don't anticipate
wrong expectations for driver authors.

Reviewed-by: Tom Rix  (For fpga)
Reviewed-by: Mathieu Poirier 
Reviewed-by: Cornelia Huck  (For drivers/s390 and drivers/vfio)
Acked-by: Russell King (Oracle)  (For ARM, Amba and related parts)
Acked-by: Mark Brown 
Acked-by: Chen-Yu Tsai  (for sunxi-rsb)
Acked-by: Pali Rohár 
Acked-by: Mauro Carvalho Chehab  (for media)
Acked-by: Hans de Goede  (For drivers/platform)
Acked-by: Alexandre Belloni 
Acked-By: Vinod Koul 
Acked-by: Juergen Gross  (For xen)
Acked-by: Lee Jones  (For mfd)
Acked-by: Johannes Thumshirn  (For mcb)
Acked-by: Johan Hovold 
Acked-by: Srinivas Kandagatla  (For slimbus)
Acked-by: Kirti Wankhede  (For vfio)
Acked-by: Maximilian Luz 
Acked-by: Heikki Krogerus  (For ulpi and typec)
Acked-by: Samuel Iglesias Gonsálvez  (For ipack)
Acked-by: Geoff Levand  (For ps3)
Acked-by: Yehezkel Bernat  (For thunderbolt)
Acked-by: Alexander Shishkin  (For intel_th)
Acked-by: Dominik Brodowski  (For pcmcia)
Acked-by: Rafael J. Wysocki  (For ACPI)
Acked-by: Bjorn Andersson  (rpmsg and apr)
Acked-by: Srinivas Pandruvada  (For intel-ish-hid)
Acked-by: Dan Williams  (For CXL, DAX, and NVDIMM)
Acked-by: William Breathitt Gray  (For isa)
Acked-by: Stefan Richter  (For firewire)
Acked-by: Benjamin Tissoires  (For hid)
Acked-by: Thorsten Scherer  (For siox)
Acked-by: Sven Van Asbroeck  (For anybuss)
Acked-by: Ulf Hansson  (For MMC)
Acked-by: Wolfram Sang  # for I2C
Acked-by: Sudeep Holla 
Acked-by: Geert Uytterhoeven 
Acked-by: Dmitry Torokhov 
Acked-by: Finn Thain 
Signed-off-by: Uwe Kleine-König 
Link: https://lore.kernel.org/r/20210713193522.1770306-6-u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman

dax: avoid -Wempty-body warnings

2021-03-22T16:20:06+00:00

gcc warns about an empty body in an else statement:

drivers/dax/bus.c: In function 'do_id_store':
drivers/dax/bus.c:94:48: error: suggest braces around empty body in an 'else' statement [-Werror=empty-body]
   94 |                         /* nothing to remove */;
      |                                                ^
drivers/dax/bus.c:99:43: error: suggest braces around empty body in an 'else' statement [-Werror=empty-body]
   99 |                 /* dax_id already added */;
      |                                           ^

In both of these cases, the 'else' exists only to have a place to
add a comment, but that comment doesn't really explain that much
either, so the easiest way to shut up that warning is to just
remove the else.

Signed-off-by: Arnd Bergmann 
Link: https://lore.kernel.org/r/20210322114514.3490752-1-arnd@kernel.org
Signed-off-by: Dan Williams

dax-device: Make remove callback return void

2021-02-17T03:45:13+00:00

The driver core ignores the return value of struct bus_type::remove()
because there is only little that can be done. To simplify the quest to
make this function return void, let struct dax_device_driver::remove()
return void, too. All users already unconditionally return 0, this commit
makes it obvious that returning an error code isn't intended.

Signed-off-by: Uwe Kleine-König 
Link: https://lore.kernel.org/r/20210205222842.34896-6-uwe@kleine-koenig.org
Signed-off-by: Dan Williams

device-dax: Fix error path in dax_driver_register

2021-02-17T03:42:03+00:00

The static variable match_always_count is supposed to track if there is
a driver registered that has .match_always set. If driver_register()
fails, the previous increment must be undone.

Signed-off-by: Uwe Kleine-König 
Link: https://lore.kernel.org/r/20210205222842.34896-4-uwe@kleine-koenig.org
Signed-off-by: Dan Williams