linux.git/drivers/dax/bus.c, branch v5.16

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

device-dax: Properly handle drivers without remove callback

2021-02-17T03:41:26+00:00

If all resources are allocated in .probe() using devm_ functions it
might make sense to not provide a .remove() callback. Then the right
thing is to just return success.

Signed-off-by: Uwe Kleine-König 
Link: https://lore.kernel.org/r/20210205222842.34896-3-uwe@kleine-koenig.org
Signed-off-by: Dan Williams

device-dax: Prevent registering drivers without probe callback

2021-02-17T03:40:20+00:00

The bus probe function dax_bus_probe() calls the probe callback without
checking it to be non-NULL. Prevent a NULL pointer exception if a driver
without a probe function is registered by refusing to register this
driver.

Signed-off-by: Uwe Kleine-König 
Link: https://lore.kernel.org/r/20210205222842.34896-2-uwe@kleine-koenig.org
Signed-off-by: Dan Williams

device-dax: Fix default return code of range_parse()

2021-02-16T22:37:43+00:00

The return value of range_parse() indicates the size when it is
positive.  The error code should be negative.

Signed-off-by: Shiyang Ruan 
Reviewed-by: Joao Martins 
Link: https://lore.kernel.org/r/20210126021331.1059933-1-ruansy.fnst@cn.fujitsu.com
Reported-by: Zhang Qilong 
Fixes: 8490e2e25b5a ("device-dax: add a range mapping allocation attribute")
Signed-off-by: Dan Williams

device-dax: Avoid an unnecessary check in alloc_dev_dax_range()

2020-12-24T18:06:57+00:00

Swap the calling sequence of krealloc() and __request_region(), call the
latter first. In this way, the value of dev_dax->nr_range does not need to
be considered when __request_region() failed.

Signed-off-by: Zhen Lei 
Link: https://lore.kernel.org/r/20201219081840.1149-2-thunder.leizhen@huawei.com
Signed-off-by: Dan Williams

device-dax: Fix range release

2020-12-24T18:06:13+00:00

There are multiple locations that open-code the release of the last
range in a device-dax instance. Consolidate this into a new
dev_dax_trim_range() helper.

This also addresses a kmemleak report:

# cat /sys/kernel/debug/kmemleak
[..]
unreferenced object 0xffff976bd46f6240 (size 64):
   comm "ndctl", pid 23556, jiffies 4299514316 (age 5406.733s)
   hex dump (first 32 bytes):
     00 00 00 00 00 00 00 00 00 00 20 c3 37 00 00 00  .......... .7...
     ff ff ff 7f 38 00 00 00 00 00 00 00 00 00 00 00  ....8...........
   backtrace:
     [<00000000064003cf>] __kmalloc_track_caller+0x136/0x379
     [<00000000d85e3c52>] krealloc+0x67/0x92
     [<00000000d7d3ba8a>] __alloc_dev_dax_range+0x73/0x25c
     [<0000000027d58626>] devm_create_dev_dax+0x27d/0x416
     [<00000000434abd43>] __dax_pmem_probe+0x1c9/0x1000 [dax_pmem_core]
     [<0000000083726c1c>] dax_pmem_probe+0x10/0x1f [dax_pmem]
     [<00000000b5f2319c>] nvdimm_bus_probe+0x9d/0x340 [libnvdimm]
     [<00000000c055e544>] really_probe+0x230/0x48d
     [<000000006cabd38e>] driver_probe_device+0x122/0x13b
     [<0000000029c7b95a>] device_driver_attach+0x5b/0x60
     [<0000000053e5659b>] bind_store+0xb7/0xc3
     [<00000000d3bdaadc>] drv_attr_store+0x27/0x31
     [<00000000949069c5>] sysfs_kf_write+0x4a/0x57
     [<000000004a8b5adf>] kernfs_fop_write+0x150/0x1e5
     [<00000000bded60f0>] __vfs_write+0x1b/0x34
     [<00000000b92900f0>] vfs_write+0xd8/0x1d1

Reported-by: Jane Chu 
Cc: Zhen Lei 
Link: https://lore.kernel.org/r/160834570161.1791850.14911670304441510419.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams

device-dax: delete a redundancy check in dev_dax_validate_align()

2020-12-17T21:52:28+00:00

After we have done the alignment check for the length of each range, the
alignment check for dev_dax_size(dev_dax) is no longer needed, because it
get the sum of the length of each range.

Signed-off-by: Zhen Lei 
Link: https://lore.kernel.org/r/20201120092057.2144-1-thunder.leizhen@huawei.com
Signed-off-by: Dan Williams