Message	SHA1
treewide: import latest Galaxy A52 5G kernel ... * this imports the latest version of SM-A526B kernel from https://opensource.samsung.com/uploadSearch?searchValue=SM-A526B itsaschoolbus   commited 2026-09-27 19:03:59 +07:00	34794f4cb2
eventpoll.h: wrap casts in () properly ... When importing the latest copy of the kernel headers into Bionic, Christpher and Elliott noticed that the eventpoll.h casts were not wrapped in (). As it is, clang complains about macros without surrounding (), so this makes it a pain for userspace tools. So fix it up by adding another () pair, and make them line up purty by using tabs. Fixes: 65aaf87b3a ("add EPOLLNVAL, annotate EPOLL... and event_poll->event") Reported-by: Christopher Ferris <cferris@google.com> Reported-by: Elliott Hughes <enh@google.com> Cc: stable <stable@vger.kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Greg Kroah-Hartman   commited 2018-07-15 14:03:06 +02:00	45cd74cb50
add EPOLLNVAL, annotate EPOLL... and event_poll->event ... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Al Viro   commited 2018-02-01 16:28:55 -05:00	65aaf87b3a
License cleanup: add SPDX license identifier to uapi header files with a license ... Many user space API headers have licensing information, which is either incomplete, badly formatted or just a shorthand for referring to the license under which the file is supposed to be. This makes it hard for compliance tools to determine the correct license. Update these files with an SPDX license identifier. The identifier was chosen based on the license information in the file. GPL/LGPL licensed headers get the matching GPL/LGPL SPDX license identifier with the added 'WITH Linux-syscall-note' exception, which is the officially assigned exception identifier for the kernel syscall exception: NOTE! This copyright does *not* cover user programs that use kernel services by normal system calls - this is merely considered normal use of the kernel, and does *not* fall under the heading of "derived work". This exception makes it possible to include GPL headers into non GPL code, without confusing license compliance tools. Headers which have either explicit dual licensing or are just licensed under a non GPL license are updated with the corresponding SPDX identifier and the GPLv2 with syscall exception identifier. The format is: ((GPL-2.0 WITH Linux-syscall-note) OR SPDX-ID-OF-OTHER-LICENSE) SPDX license identifiers are a legally binding shorthand, which can be used instead of the full boiler plate text. The update does not remove existing license information as this has to be done on a case by case basis and the copyright holders might have to be consulted. This will happen in a separate step. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. See the previous patch in this series for the methodology of how this patch was researched. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Greg Kroah-Hartman   commited 2017-11-02 11:20:11 +01:00	e2be04c7f9
eventpoll.h: add missing epoll event masks ... [resend due to me forgetting to cc: linux-api the first time around I posted these back on Feb 23] From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> For some reason these values are not in the uapi header file, so any libc has to define it themselves. To prevent them from needing to do this, just have the kernel provide the correct values. Reported-by: Elliott Hughes <enh@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Greg KH   authored and   Greg Kroah-Hartman   commited 2017-03-14 09:47:33 +08:00	7e04072685
eventpoll.h: fix epoll event masks ... [resend due to me forgetting to cc: linux-api the first time around I posted these back on Feb 23] From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> When userspace tries to use these defines, it complains that it needs to be an unsigned 1 that is shifted, so libc implementations have to create their own version. Fix this by defining it properly so that libcs can just use the kernel uapi header. Reported-by: Elliott Hughes <enh@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Greg KH   authored and   Greg Kroah-Hartman   commited 2017-03-14 09:47:33 +08:00	6f051e4a68
epoll: add EPOLLEXCLUSIVE flag ... Currently, epoll file descriptors or epfds (the fd returned from epoll_create[1]()) that are added to a shared wakeup source are always added in a non-exclusive manner. This means that when we have multiple epfds attached to a shared fd source they are all woken up. This creates thundering herd type behavior. Introduce a new 'EPOLLEXCLUSIVE' flag that can be passed as part of the 'event' argument during an epoll_ctl() EPOLL_CTL_ADD operation. This new flag allows for exclusive wakeups when there are multiple epfds attached to a shared fd event source. The implementation walks the list of exclusive waiters, and queues an event to each epfd, until it finds the first waiter that has threads blocked on it via epoll_wait(). The idea is to search for threads which are idle and ready to process the wakeup events. Thus, we queue an event to at least 1 epfd, but may still potentially queue an event to all epfds that are attached to the shared fd source. Performance testing was done by Madars Vitolins using a modified version of Enduro/X. The use of the 'EPOLLEXCLUSIVE' flag reduce the length of this particular workload from 860s down to 24s. Sample epoll_clt text: EPOLLEXCLUSIVE Sets an exclusive wakeup mode for the epfd file descriptor that is being attached to the target file descriptor, fd. Thus, when an event occurs and multiple epfd file descriptors are attached to the same target file using EPOLLEXCLUSIVE, one or more epfds will receive an event with epoll_wait(2). The default in this scenario (when EPOLLEXCLUSIVE is not set) is for all epfds to receive an event. EPOLLEXCLUSIVE may only be specified with the op EPOLL_CTL_ADD. Signed-off-by: Jason Baron <jbaron@akamai.com> Tested-by: Madars Vitolins <m@silodev.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Eric Wong <normalperson@yhbt.net> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Hagen Paul Pfeifer <hagen@jauu.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Jason Baron   authored and   Linus Torvalds   commited 2016-01-20 17:09:18 -08:00	df0108c5da
epoll: drop EPOLLWAKEUP if PM_SLEEP is disabled ... Drop EPOLLWAKEUP from epoll events mask if CONFIG_PM_SLEEP is disabled. Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Amit Pundir   authored and   Rafael J. Wysocki   commited 2013-12-03 15:35:52 +01:00	95f19f658c
revert "epoll: support for disabling items, and a self-test app" ... Revert commit 03a7beb55b ("epoll: support for disabling items, and a self-test app") pending resolution of the issues identified by Michael Kerrisk, copied below. We'll revisit this for 3.8. : I've taken a look at this patch as it currently stands in 3.7-rc1, and : done a bit of testing. (By the way, the test program : tools/testing/selftests/epoll/test_epoll.c does not compile...) : : There are one or two places where the behavior seems a little strange, : so I have a question or two at the end of this mail. But other than : that, I want to check my understanding so that the interface can be : correctly documented. : : Just to go though my understanding, the problem is the following : scenario in a multithreaded application: : : 1. Multiple threads are performing epoll_wait() operations, : and maintaining a user-space cache that contains information : corresponding to each file descriptor being monitored by : epoll_wait(). : : 2. At some point, a thread wants to delete (EPOLL_CTL_DEL) : a file descriptor from the epoll interest list, and : delete the corresponding record from the user-space cache. : : 3. The problem with (2) is that some other thread may have : previously done an epoll_wait() that retrieved information : about the fd in question, and may be in the middle of using : information in the cache that relates to that fd. Thus, : there is a potential race. : : 4. The race can't solved purely in user space, because doing : so would require applying a mutex across the epoll_wait() : call, which would of course blow thread concurrency. : : Right? : : Your solution is the EPOLL_CTL_DISABLE operation. I want to : confirm my understanding about how to use this flag, since : the description that has accompanied the patches so far : has been a bit sparse : : 0. In the scenario you're concerned about, deleting a file : descriptor means (safely) doing the following: : (a) Deleting the file descriptor from the epoll interest list : using EPOLL_CTL_DEL : (b) Deleting the corresponding record in the user-space cache : : 1. It's only meaningful to use this EPOLL_CTL_DISABLE in : conjunction with EPOLLONESHOT. : : 2. Using EPOLL_CTL_DISABLE without using EPOLLONESHOT in : conjunction is a logical error. : : 3. The correct way to code multithreaded applications using : EPOLL_CTL_DISABLE and EPOLLONESHOT is as follows: : : a. All EPOLL_CTL_ADD and EPOLL_CTL_MOD operations should : should EPOLLONESHOT. : : b. When a thread wants to delete a file descriptor, it : should do the following: : : [1] Call epoll_ctl(EPOLL_CTL_DISABLE) : [2] If the return status from epoll_ctl(EPOLL_CTL_DISABLE) : was zero, then the file descriptor can be safely : deleted by the thread that made this call. : [3] If the epoll_ctl(EPOLL_CTL_DISABLE) fails with EBUSY, : then the descriptor is in use. In this case, the calling : thread should set a flag in the user-space cache to : indicate that the thread that is using the descriptor : should perform the deletion operation. : : Is all of the above correct? : : The implementation depends on checking on whether : (events & ~EP_PRIVATE_BITS) == 0 : This replies on the fact that EPOLL_CTL_AD and EPOLL_CTL_MOD always : set EPOLLHUP and EPOLLERR in the 'events' mask, and EPOLLONESHOT : causes those flags (as well as all others in ~EP_PRIVATE_BITS) to be : cleared. : : A corollary to the previous paragraph is that using EPOLL_CTL_DISABLE : is only useful in conjunction with EPOLLONESHOT. However, as things : stand, one can use EPOLL_CTL_DISABLE on a file descriptor that does : not have EPOLLONESHOT set in 'events' This results in the following : (slightly surprising) behavior: : : (a) The first call to epoll_ctl(EPOLL_CTL_DISABLE) returns 0 : (the indicator that the file descriptor can be safely deleted). : (b) The next call to epoll_ctl(EPOLL_CTL_DISABLE) fails with EBUSY. : : This doesn't seem particularly useful, and in fact is probably an : indication that the user made a logic error: they should only be using : epoll_ctl(EPOLL_CTL_DISABLE) on a file descriptor for which : EPOLLONESHOT was set in 'events'. If that is correct, then would it : not make sense to return an error to user space for this case? Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: "Paton J. Lewis" <palewis@adobe.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Andrew Morton   authored and   Linus Torvalds   commited 2012-11-09 06:41:46 +01:00	a80a6b85b4
UAPI: (Scripted) Disintegrate include/linux ... Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Dave Jones <davej@redhat.com> David Howells   commited 2012-10-13 10:46:48 +01:00	607ca46e97