From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Waiman Long <longman@redhat.com>, Ingo Molnar <mingo@kernel.org>,
Davidlohr Bueso <dbueso@suse.de>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 5.10 31/39] locking/ww_mutex: Simplify use_ww_ctx & ww_ctx handling
Date: Thu, 25 Mar 2021 07:25:50 -0400 [thread overview]
Message-ID: <20210325112558.1927423-31-sashal@kernel.org> (raw)
In-Reply-To: <20210325112558.1927423-1-sashal@kernel.org>
From: Waiman Long <longman@redhat.com>
[ Upstream commit 5de2055d31ea88fd9ae9709ac95c372a505a60fa ]
The use_ww_ctx flag is passed to mutex_optimistic_spin(), but the
function doesn't use it. The frequent use of the (use_ww_ctx && ww_ctx)
combination is repetitive.
In fact, ww_ctx should not be used at all if !use_ww_ctx. Simplify
ww_mutex code by dropping use_ww_ctx from mutex_optimistic_spin() an
clear ww_ctx if !use_ww_ctx. In this way, we can replace (use_ww_ctx &&
ww_ctx) by just (ww_ctx).
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Link: https://lore.kernel.org/r/20210316153119.13802-2-longman@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/locking/mutex.c | 25 ++++++++++++++-----------
1 file changed, 14 insertions(+), 11 deletions(-)
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 5352ce50a97e..2c25b830203c 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -636,7 +636,7 @@ static inline int mutex_can_spin_on_owner(struct mutex *lock)
*/
static __always_inline bool
mutex_optimistic_spin(struct mutex *lock, struct ww_acquire_ctx *ww_ctx,
- const bool use_ww_ctx, struct mutex_waiter *waiter)
+ struct mutex_waiter *waiter)
{
if (!waiter) {
/*
@@ -712,7 +712,7 @@ mutex_optimistic_spin(struct mutex *lock, struct ww_acquire_ctx *ww_ctx,
#else
static __always_inline bool
mutex_optimistic_spin(struct mutex *lock, struct ww_acquire_ctx *ww_ctx,
- const bool use_ww_ctx, struct mutex_waiter *waiter)
+ struct mutex_waiter *waiter)
{
return false;
}
@@ -932,6 +932,9 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
struct ww_mutex *ww;
int ret;
+ if (!use_ww_ctx)
+ ww_ctx = NULL;
+
might_sleep();
#ifdef CONFIG_DEBUG_MUTEXES
@@ -939,7 +942,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
#endif
ww = container_of(lock, struct ww_mutex, base);
- if (use_ww_ctx && ww_ctx) {
+ if (ww_ctx) {
if (unlikely(ww_ctx == READ_ONCE(ww->ctx)))
return -EALREADY;
@@ -956,10 +959,10 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, ip);
if (__mutex_trylock(lock) ||
- mutex_optimistic_spin(lock, ww_ctx, use_ww_ctx, NULL)) {
+ mutex_optimistic_spin(lock, ww_ctx, NULL)) {
/* got the lock, yay! */
lock_acquired(&lock->dep_map, ip);
- if (use_ww_ctx && ww_ctx)
+ if (ww_ctx)
ww_mutex_set_context_fastpath(ww, ww_ctx);
preempt_enable();
return 0;
@@ -970,7 +973,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
* After waiting to acquire the wait_lock, try again.
*/
if (__mutex_trylock(lock)) {
- if (use_ww_ctx && ww_ctx)
+ if (ww_ctx)
__ww_mutex_check_waiters(lock, ww_ctx);
goto skip_wait;
@@ -1023,7 +1026,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
goto err;
}
- if (use_ww_ctx && ww_ctx) {
+ if (ww_ctx) {
ret = __ww_mutex_check_kill(lock, &waiter, ww_ctx);
if (ret)
goto err;
@@ -1036,7 +1039,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
* ww_mutex needs to always recheck its position since its waiter
* list is not FIFO ordered.
*/
- if ((use_ww_ctx && ww_ctx) || !first) {
+ if (ww_ctx || !first) {
first = __mutex_waiter_is_first(lock, &waiter);
if (first)
__mutex_set_flag(lock, MUTEX_FLAG_HANDOFF);
@@ -1049,7 +1052,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
* or we must see its unlock and acquire.
*/
if (__mutex_trylock(lock) ||
- (first && mutex_optimistic_spin(lock, ww_ctx, use_ww_ctx, &waiter)))
+ (first && mutex_optimistic_spin(lock, ww_ctx, &waiter)))
break;
spin_lock(&lock->wait_lock);
@@ -1058,7 +1061,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
acquired:
__set_current_state(TASK_RUNNING);
- if (use_ww_ctx && ww_ctx) {
+ if (ww_ctx) {
/*
* Wound-Wait; we stole the lock (!first_waiter), check the
* waiters as anyone might want to wound us.
@@ -1078,7 +1081,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
/* got the lock - cleanup and rejoice! */
lock_acquired(&lock->dep_map, ip);
- if (use_ww_ctx && ww_ctx)
+ if (ww_ctx)
ww_mutex_lock_acquired(ww, ww_ctx);
spin_unlock(&lock->wait_lock);
--
2.30.1
next prev parent reply other threads:[~2021-03-25 11:31 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-25 11:25 [PATCH AUTOSEL 5.10 01/39] virtiofs: Fail dax mount if device does not support it Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 02/39] ext4: shrink race window in ext4_should_retry_alloc() Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 03/39] ext4: add reclaim checks to xattr code Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 04/39] fs/ext4: fix integer overflow in s_log_groups_per_flex Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 05/39] ext4: fix bh ref count on error paths Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 06/39] fs: nfsd: fix kconfig dependency warning for NFSD_V4 Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 07/39] rpc: fix NULL dereference on kmalloc failure Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 08/39] iomap: Fix negative assignment to unsigned sis->pages in iomap_swapfile_activate Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 09/39] ASoC: rt1015: fix i2c communication error Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 10/39] ASoC: rt5640: Fix dac- and adc- vol-tlv values being off by a factor of 10 Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 11/39] ASoC: rt5651: " Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 12/39] ASoC: sgtl5000: set DAP_AVC_CTRL register to correct default value on probe Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 13/39] ASoC: es8316: Simplify adc_pga_gain_tlv table Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 14/39] ASoC: soc-core: Prevent warning if no DMI table is present Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 15/39] ASoC: cs42l42: Fix Bitclock polarity inversion Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 16/39] ASoC: cs42l42: Fix channel width support Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 17/39] ASoC: cs42l42: Fix mixer volume control Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 18/39] ASoC: cs42l42: Always wait at least 3ms after reset Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 19/39] NFSD: fix error handling in NFSv4.0 callbacks Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 20/39] kernel: freezer should treat PF_IO_WORKER like PF_KTHREAD for freezing Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 21/39] powerpc: Force inlining of cpu_has_feature() to avoid build failure Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 22/39] vhost: Fix vhost_vq_reset() Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 23/39] io_uring: fix ->flags races by linked timeouts Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 24/39] scsi: st: Fix a use after free in st_open() Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 25/39] scsi: qla2xxx: Fix broken #endif placement Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 26/39] staging: comedi: cb_pcidas: fix request_irq() warn Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 27/39] staging: comedi: cb_pcidas64: " Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 28/39] ASoC: rt5659: Update MCLK rate in set_sysclk() Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 29/39] ASoC: rt711: add snd_soc_component remove callback Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 30/39] thermal/core: Add NULL pointer check before using cooling device stats Sasha Levin
2021-03-25 11:25 ` Sasha Levin [this message]
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 32/39] locking/ww_mutex: Fix acquire/release imbalance in ww_acquire_init()/ww_acquire_fini() Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 33/39] nvmet-tcp: fix kmap leak when data digest in use Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 34/39] io_uring: imply MSG_NOSIGNAL for send[msg]()/recv[msg]() calls Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 35/39] static_call: Align static_call_is_init() patching condition Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 36/39] ext4: do not iput inode under running transaction in ext4_rename() Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 37/39] signal: don't allow sending any signals to PF_IO_WORKER threads Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 38/39] signal: don't allow STOP on " Sasha Levin
2021-03-25 11:25 ` [PATCH AUTOSEL 5.10 39/39] io_uring: call req_set_fail_links() on short send[msg]()/recv[msg]() with MSG_WAITALL Sasha Levin
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