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authorLinus Torvalds <torvalds@linux-foundation.org>2019-03-09 09:56:17 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-09 09:56:17 -0800
commit1a29e857507046e413ca7a4a7c9cd32fed9ea255 (patch)
tree5a46d9c4dcab39fc588a9ac2c9f5e4c866d41254 /Documentation/filesystems/sysfs.txt
parentc4703acd6d4a58dc4b31ad2a8f8b14becb898d25 (diff)
parent4064174becc09a5a2385a27c8a6fd40888b0e13c (diff)
Merge tag 'docs-5.1' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet: "A fairly routine cycle for docs - lots of typo fixes, some new documents, and more translations. There's also some LICENSES adjustments from Thomas" * tag 'docs-5.1' of git://git.lwn.net/linux: (74 commits) docs: Bring some order to filesystem documentation Documentation/locking/lockdep: Drop last two chars of sample states doc: rcu: Suspicious RCU usage is a warning docs: driver-api: iio: fix errors in documentation Documentation/process/howto: Update for 4.x -> 5.x versioning docs: Explicitly state that the 'Fixes:' tag shouldn't split lines doc: security: Add kern-doc for lsm_hooks.h doc: sctp: Merge and clean up rst files Docs: Correct /proc/stat path scripts/spdxcheck.py: fix C++ comment style detection doc: fix typos in license-rules.rst Documentation: fix admin-guide/README.rst minimum gcc version requirement doc: process: complete removal of info about -git patches doc: translations: sync translations 'remove info about -git patches' perf-security: wrap paragraphs on 72 columns perf-security: elaborate on perf_events/Perf privileged users perf-security: document collected perf_events/Perf data categories perf-security: document perf_events/Perf resource control sysfs.txt: add note on available attribute macros docs: kernel-doc: typo "if ... if" -> "if ... is" ...
Diffstat (limited to 'Documentation/filesystems/sysfs.txt')
-rw-r--r--Documentation/filesystems/sysfs.txt21
1 files changed, 21 insertions, 0 deletions
diff --git a/Documentation/filesystems/sysfs.txt b/Documentation/filesystems/sysfs.txt
index 41411b0c60a3..5b5311f9358d 100644
--- a/Documentation/filesystems/sysfs.txt
+++ b/Documentation/filesystems/sysfs.txt
@@ -116,6 +116,27 @@ static struct device_attribute dev_attr_foo = {
.store = store_foo,
};
+Note as stated in include/linux/kernel.h "OTHER_WRITABLE? Generally
+considered a bad idea." so trying to set a sysfs file writable for
+everyone will fail reverting to RO mode for "Others".
+
+For the common cases sysfs.h provides convenience macros to make
+defining attributes easier as well as making code more concise and
+readable. The above case could be shortened to:
+
+static struct device_attribute dev_attr_foo = __ATTR_RW(foo);
+
+the list of helpers available to define your wrapper function is:
+__ATTR_RO(name): assumes default name_show and mode 0444
+__ATTR_WO(name): assumes a name_store only and is restricted to mode
+ 0200 that is root write access only.
+__ATTR_RO_MODE(name, mode): fore more restrictive RO access currently
+ only use case is the EFI System Resource Table
+ (see drivers/firmware/efi/esrt.c)
+__ATTR_RW(name): assumes default name_show, name_store and setting
+ mode to 0644.
+__ATTR_NULL: which sets the name to NULL and is used as end of list
+ indicator (see: kernel/workqueue.c)
Subsystem-Specific Callbacks
~~~~~~~~~~~~~~~~~~~~~~~~~~~~