Changes in dec_unless_positive

cdd5b5a9761fd66d17586e4f4ba6588c70e640ea - Merge branch 'next' into for-linus

Tue, 07 Nov 2023 00:42:08 +0100

Merge branch 'next' into for-linusPrepare input updates for 6.7 merge window. List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive

34069d12e239ae8f36dd96c378e4622fb1c42a76 - Merge tag 'v6.5' into next

Tue, 05 Sep 2023 23:08:14 +0200

Merge tag 'v6.5' into nextSync up with mainline to bring in updates to the shared infrastructure. List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive

2612e3bbc0386368a850140a6c9b990cd496a5ec - Merge drm/drm-next into drm-intel-next

Mon, 07 Aug 2023 23:14:42 +0200

Merge drm/drm-next into drm-intel-nextCatching-up with drm-next and drm-intel-gt-next.It will unblock a code refactor around the platformdefinitions (names vs acronyms).Signed-off-by: Rodrigo Vivi List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive

9f771739a04919226081a107167596de75108fbb - Merge drm/drm-next into drm-intel-gt-next

Mon, 07 Aug 2023 12:29:40 +0200

Merge drm/drm-next into drm-intel-gt-nextNeed to pull in b3e4aae612ec ("drm/i915/hdcp: Modify hdcp_gsc_message msg sending mechanism") asa dependency for https://patchwork.freedesktop.org/series/121735/Signed-off-by: Joonas Lahtinen List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive

61b7369483efb5e0a9f3b48e75fac00d46d661e0 - Merge drm/drm-next into drm-misc-next

Mon, 24 Jul 2023 15:44:47 +0200

Merge drm/drm-next into drm-misc-nextBackmerging to get v6.5-rc2.Signed-off-by: Thomas Zimmermann List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive

0791faebfe750292a8a842b64795a390ca4a3b51 - ASoC: Merge v6.5-rc2

Mon, 17 Jul 2023 07:12:31 +0200

ASoC: Merge v6.5-rc2Get a similar baseline to my other branches, and fixes for people usingthe branch. List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive

2f98e686ef59b5d19af5847d755798e2031bee3a - Merge v6.5-rc1 into drm-misc-fixes

Tue, 11 Jul 2023 09:23:20 +0200

Merge v6.5-rc1 into drm-misc-fixesBoris needs 6.5-rc1 in drm-misc-fixes to prevent a conflict.Signed-off-by: Maxime Ripard List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive

44f10dbefd5e41b3385af91f855a57aa2afaf40e - Merge branch 'master' into mm-hotfixes-stable

Fri, 30 Jun 2023 17:41:39 +0200

Merge branch 'master' into mm-hotfixes-stable List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive

bc6cb4d5bc3a44197de30784eae71d8ba28483eb - Merge tag 'locking-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Tue, 27 Jun 2023 23:14:30 +0200

Merge tag 'locking-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipPull locking updates from Ingo Molnar: - Introduce cmpxchg128() -- aka. the demise of cmpxchg_double() The cmpxchg128() family of functions is basically & functionally the same as cmpxchg_double(), but with a saner interface. Instead of a 6-parameter horror that forced u128 - u64/u64-halves layout details on the interface and exposed users to complexity, fragility & bugs, use a natural 3-parameter interface with u128 types. - Restructure the generated atomic headers, and add kerneldoc comments for all of the generic atomic{,64,_long}_t operations. The generated definitions are much cleaner now, and come with documentation. - Implement lock_set_cmp_fn() on lockdep, for defining an ordering when taking multiple locks of the same type. This gets rid of one use of lockdep_set_novalidate_class() in the bcache code. - Fix raw_cpu_generic_try_cmpxchg() bug due to an unintended variable shadowing generating garbage code on Clang on certain ARM builds.* tag 'locking-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (43 commits) locking/atomic: scripts: fix ${atomic}_dec_if_positive() kerneldoc percpu: Fix self-assignment of __old in raw_cpu_generic_try_cmpxchg() locking/atomic: treewide: delete arch_atomic_*() kerneldoc locking/atomic: docs: Add atomic operations to the driver basic API documentation locking/atomic: scripts: generate kerneldoc comments docs: scripts: kernel-doc: accept bitwise negation like ~@var locking/atomic: scripts: simplify raw_atomic*() definitions locking/atomic: scripts: simplify raw_atomic_long*() definitions locking/atomic: scripts: split pfx/name/sfx/order locking/atomic: scripts: restructure fallback ifdeffery locking/atomic: scripts: build raw_atomic_long*() directly locking/atomic: treewide: use raw_atomic*_() locking/atomic: scripts: add trivial raw_atomic*_() locking/atomic: scripts: factor out order template generation locking/atomic: scripts: remove leftover "${mult}" locking/atomic: scripts: remove bogus order parameter locking/atomic: xtensa: add preprocessor symbols locking/atomic: x86: add preprocessor symbols locking/atomic: sparc: add preprocessor symbols locking/atomic: sh: add preprocessor symbols ... List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive

1d78814d41701c216e28fcf2656526146dec4a1a - locking/atomic: scripts: simplify raw_atomic*() definitions

Mon, 05 Jun 2023 09:01:20 +0200

locking/atomic: scripts: simplify raw_atomic*() definitionsCurrently each ordering variant has several potential definitions,with a mixture of preprocessor and C definitions, including severalcopies of its C prototype, e.g.| #if defined(arch_atomic_fetch_andnot_acquire)| #define raw_atomic_fetch_andnot_acquire arch_atomic_fetch_andnot_acquire| #elif defined(arch_atomic_fetch_andnot_relaxed)| static __always_inline int| raw_atomic_fetch_andnot_acquire(int i, atomic_t *v)| {| int ret = arch_atomic_fetch_andnot_relaxed(i, v);| __atomic_acquire_fence();| return ret;| }| #elif defined(arch_atomic_fetch_andnot)| #define raw_atomic_fetch_andnot_acquire arch_atomic_fetch_andnot| #else| static __always_inline int| raw_atomic_fetch_andnot_acquire(int i, atomic_t *v)| {| return raw_atomic_fetch_and_acquire(~i, v);| }| #endifMake this a bit simpler by defining the C prototype once, and writingthe various potential definitions as plain C code guarded by ifdeffery.For example, the above becomes:| static __always_inline int| raw_atomic_fetch_andnot_acquire(int i, atomic_t *v)| {| #if defined(arch_atomic_fetch_andnot_acquire)| return arch_atomic_fetch_andnot_acquire(i, v);| #elif defined(arch_atomic_fetch_andnot_relaxed)| int ret = arch_atomic_fetch_andnot_relaxed(i, v);| __atomic_acquire_fence();| return ret;| #elif defined(arch_atomic_fetch_andnot)| return arch_atomic_fetch_andnot(i, v);| #else| return raw_atomic_fetch_and_acquire(~i, v);| #endif| }Which is far easier to read. As we now always have a single copy of theC prototype wrapping all the potential definitions, we now have anobvious single location for kerneldoc comments.At the same time, the fallbacks for raw_atomic*_xhcg() are made to use'new' rather than 'i' as the name of the new value. This is what theexisting fallback template used, and is more consistent with theraw_atomic{_try,}cmpxchg() fallbacks.There should be no functional change as a result of this patch.Signed-off-by: Mark Rutland Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Kees Cook Link: https://lore.kernel.org/r/20230605070124.3741859-24-mark.rutland@arm.com List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive

9257959a6e5b4fca6fc8e985790bff62c2046f20 - locking/atomic: scripts: restructure fallback ifdeffery

Mon, 05 Jun 2023 09:01:17 +0200

locking/atomic: scripts: restructure fallback ifdefferyCurrently the various ordering variants of an atomic operation aredefined in groups of full/acquire/release/relaxed ordering variants withsome shared ifdeffery and several potential definitions of each orderingvariant in different branches of the shared ifdeffery.As an ordering variant can have several potential definitions downdifferent branches of the shared ifdeffery, it can be painful for ahuman to find a relevant definition, and we don't have a good locationto place anything common to all definitions of an ordering variant (e.g.kerneldoc).Historically the grouping of full/acquire/release/relaxed orderingvariants was necessary as we filled in the missing atomics in the samenamespace as the architecture used. It would be easy to accidentallydefine one ordering fallback in terms of another ordering fallback withredundant barriers, and avoiding that would otherwise require a lot ofbaroque ifdeffery.With recent changes we no longer need to fill in the missing atomics inthe arch_atomic*_() namespace, and only need to fill in theraw_atomic*_() namespace. Due to this, there's no risk of anamespace collision, and we can define each raw_atomic*_ orderingvariant with its own ifdeffery checking for the arch_atomic*_ordering variants.Restructure the fallbacks in this way, with each ordering variant havingits own ifdeffery of the form:| #if defined(arch_atomic_fetch_andnot_acquire)| #define raw_atomic_fetch_andnot_acquire arch_atomic_fetch_andnot_acquire| #elif defined(arch_atomic_fetch_andnot_relaxed)| static __always_inline int| raw_atomic_fetch_andnot_acquire(int i, atomic_t *v)| {| int ret = arch_atomic_fetch_andnot_relaxed(i, v);| __atomic_acquire_fence();| return ret;| }| #elif defined(arch_atomic_fetch_andnot)| #define raw_atomic_fetch_andnot_acquire arch_atomic_fetch_andnot| #else| static __always_inline int| raw_atomic_fetch_andnot_acquire(int i, atomic_t *v)| {| return raw_atomic_fetch_and_acquire(~i, v);| }| #endifNote that where there's no relevant arch_atomic*_() orderingvariant, we'll define the operation in terms of a distinctraw_atomic*_(), as this itself might have been filled in with afallback.As we now generate the raw_atomic*_() implementations directly, weno longer need the trivial wrappers, so they are removed.This makes the ifdeffery easier to follow, and will allow for furtherimprovements in subsequent patches.There should be no functional change as a result of this patch.Signed-off-by: Mark Rutland Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Kees Cook Link: https://lore.kernel.org/r/20230605070124.3741859-21-mark.rutland@arm.com List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive

762f99f4f3cb41a775b5157dd761217beba65873 - Merge branch 'next' into for-linus

Sat, 15 Jan 2022 21:09:44 +0100

Merge branch 'next' into for-linusPrepare input updates for 5.17 merge window. List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive

8632987380765dee716d460640aa58d58d52998e - Merge branch 'reset/of-get-optional-exclusive' of git://git.pengutronix.de/pza/linux into timers/drivers/next

Thu, 09 Dec 2021 13:57:57 +0100

Merge branch 'reset/of-get-optional-exclusive' of git://git.pengutronix.de/pza/linux into timers/drivers/next"Add optional variant of of_reset_control_get_exclusive(). If therequested reset is not specified in the device tree, this functionreturns NULL instead of an error."This dependency is needed for the Generic Timer Module (a.k.a OSTM)support for RZ/G2L.Signed-off-by: Daniel Lezcano List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive

5d8dfaa71d87f742c53309b95cb6a8b274119027 - Merge tag 'v5.15' into next

Thu, 09 Dec 2021 08:43:50 +0100

Merge tag 'v5.15' into nextSync up with the mainline to get the latest APIs and DT bindings. List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive

e700ac213a0f793fb4f83098413303e3dd080892 - Merge branch 'pruss-fix' into fixes

Wed, 06 Oct 2021 06:55:44 +0200

Merge branch 'pruss-fix' into fixesMerge in a fix for pruss reset issue caused by enabling pruss for am335x. List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive

ffb1e76f4f32d2b8ea4189df0484980370476395 - Merge tag 'v5.15-rc2' into spi-5.15

Mon, 20 Sep 2021 16:56:58 +0200

Merge tag 'v5.15-rc2' into spi-5.15Linux 5.15-rc2 List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive

d1b803f4ca4f25d6f171219d039f9410a10b29ee - Merge drm/drm-next into drm-intel-next

Wed, 15 Sep 2021 16:12:51 +0200

Merge drm/drm-next into drm-intel-nextCatch-up on 5.15-rc1 and sync with drm-intel-gt-nextto prepare the PXP topic branch.Signed-off-by: Rodrigo Vivi List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive

d5dd580deb54483cce0cb5bbe3f1a132a28c767d - Merge drm/drm-next into drm-intel-gt-next

Wed, 15 Sep 2021 12:23:27 +0200

Merge drm/drm-next into drm-intel-gt-nextClose the divergence which has caused patches not to apply andhave a solid baseline for the PXP patches that Rodrigo will senda topic branch PR for.Signed-off-by: Joonas Lahtinen List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive

2f76520561d01a5f37e6d6ed2c2e441b6a355a96 - Merge drm/drm-next into drm-misc-next

Tue, 14 Sep 2021 09:25:30 +0200

Merge drm/drm-next into drm-misc-nextKickstart new drm-misc-next cycle.Signed-off-by: Maxime Ripard List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive

e5e726f7bb9f711102edea7e5bd511835640e3b4 - Merge tag 'locking-core-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Mon, 30 Aug 2021 23:26:36 +0200

Merge tag 'locking-core-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipPull locking and atomics updates from Thomas Gleixner: "The regular pile: - A few improvements to the mutex code - Documentation updates for atomics to clarify the difference between cmpxchg() and try_cmpxchg() and to explain the forward progress expectations. - Simplification of the atomics fallback generator - The addition of arch_atomic_long*() variants and generic arch_*() bitops based on them. - Add the missing might_sleep() invocations to the down*() operations of semaphores. The PREEMPT_RT locking core: - Scheduler updates to support the state preserving mechanism for 'sleeping' spin- and rwlocks on RT. This mechanism is carefully preserving the state of the task when blocking on a 'sleeping' spin- or rwlock and takes regular wake-ups targeted at the same task into account. The preserved or updated (via a regular wakeup) state is restored when the lock has been acquired. - Restructuring of the rtmutex code so it can be utilized and extended for the RT specific lock variants. - Restructuring of the ww_mutex code to allow sharing of the ww_mutex specific functionality for rtmutex based ww_mutexes. - Header file disentangling to allow substitution of the regular lock implementations with the PREEMPT_RT variants without creating an unmaintainable #ifdef mess. - Shared base code for the PREEMPT_RT specific rw_semaphore and rwlock implementations. Contrary to the regular rw_semaphores and rwlocks the PREEMPT_RT implementation is writer unfair because it is infeasible to do priority inheritance on multiple readers. Experience over the years has shown that real-time workloads are not the typical workloads which are sensitive to writer starvation. The alternative solution would be to allow only a single reader which has been tried and discarded as it is a major bottleneck especially for mmap_sem. Aside of that many of the writer starvation critical usage sites have been converted to a writer side mutex/spinlock and RCU read side protections in the past decade so that the issue is less prominent than it used to be. - The actual rtmutex based lock substitutions for PREEMPT_RT enabled kernels which affect mutex, ww_mutex, rw_semaphore, spinlock_t and rwlock_t. The spin/rw_lock*() functions disable migration across the critical section to preserve the existing semantics vs per-CPU variables. - Rework of the futex REQUEUE_PI mechanism to handle the case of early wake-ups which interleave with a re-queue operation to prevent the situation that a task would be blocked on both the rtmutex associated to the outer futex and the rtmutex based hash bucket spinlock. While this situation cannot happen on !RT enabled kernels the changes make the underlying concurrency problems easier to understand in general. As a result the difference between !RT and RT kernels is reduced to the handling of waiting for the critical section. !RT kernels simply spin-wait as before and RT kernels utilize rcu_wait(). - The substitution of local_lock for PREEMPT_RT with a spinlock which protects the critical section while staying preemptible. The CPU locality is established by disabling migration. The underlying concepts of this code have been in use in PREEMPT_RT for way more than a decade. The code has been refactored several times over the years and this final incarnation has been optimized once again to be as non-intrusive as possible, i.e. the RT specific parts are mostly isolated. It has been extensively tested in the 5.14-rt patch series and it has been verified that !RT kernels are not affected by these changes"* tag 'locking-core-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (92 commits) locking/rtmutex: Return success on deadlock for ww_mutex waiters locking/rtmutex: Prevent spurious EDEADLK return caused by ww_mutexes locking/rtmutex: Dequeue waiter on ww_mutex deadlock locking/rtmutex: Dont dereference waiter lockless locking/semaphore: Add might_sleep() to down_*() family locking/ww_mutex: Initialize waiter.ww_ctx properly static_call: Update API documentation locking/local_lock: Add PREEMPT_RT support locking/spinlock/rt: Prepare for RT local_lock locking/rtmutex: Add adaptive spinwait mechanism locking/rtmutex: Implement equal priority lock stealing preempt: Adjust PREEMPT_LOCK_OFFSET for RT locking/rtmutex: Prevent lockdep false positive with PI futexes futex: Prevent requeue_pi() lock nesting issue on RT futex: Simplify handle_early_requeue_pi_wakeup() futex: Reorder sanity checks in futex_requeue() futex: Clarify comment in futex_requeue() futex: Restructure futex_requeue() futex: Correct the number of requeued waiters for PI futex: Remove bogus condition for requeue PI ... List of files: /linux/scripts/atomic/fallbacks/dec_unless_positive