--- /dev/null
+From a2faee6d0dac6e5232255da9afda4d9ed6cfb6e5 Mon Sep 17 00:00:00 2001
+From: Malte Skarupke <malteskarupke@fastmail.fm>
+Date: Tue, 17 Jun 2025 01:37:12 -0700
+Subject: [PATCH] nptl: Fix indentation
+
+In my previous change I turned a nested loop into a simple loop. I'm doing
+the resulting indentation changes in a separate commit to make the diff on
+the previous commit easier to review.
+
+The following commits have been cherry-picked from Glibc master branch:
+Bug : https://sourceware.org/bugzilla/show_bug.cgi?id=25847
+
+Upstream-Status: Backport
+[https://sourceware.org/git/?p=glibc.git;a=commit;h=ee6c14ed59d480720721aaacc5fb03213dc153da]
+
+Signed-off-by: Sunil Dora <sunilkumar.dora@windriver.com>
+---
+ nptl/pthread_cond_wait.c | 132 ++++++++++++++++-----------------------
+ 1 file changed, 54 insertions(+), 78 deletions(-)
+
+diff --git a/nptl/pthread_cond_wait.c b/nptl/pthread_cond_wait.c
+index 5c86880105..104ebd48ca 100644
+--- a/nptl/pthread_cond_wait.c
++++ b/nptl/pthread_cond_wait.c
+@@ -410,87 +410,63 @@ __pthread_cond_wait_common (pthread_cond_t *cond, pthread_mutex_t *mutex,
+ return err;
+ }
+
+-
+- while (1)
+- {
+- /* Now wait until a signal is available in our group or it is closed.
+- Acquire MO so that if we observe (signals == lowseq) after group
+- switching in __condvar_quiesce_and_switch_g1, we synchronize with that
+- store and will see the prior update of __g1_start done while switching
+- groups too. */
+- unsigned int signals = atomic_load_acquire (cond->__data.__g_signals + g);
+- uint64_t g1_start = __condvar_load_g1_start_relaxed (cond);
+- unsigned int lowseq = (g1_start & 1) == g ? signals : g1_start & ~1U;
+-
+- if (seq < (g1_start >> 1))
+- {
+- /* If the group is closed already,
+- then this waiter originally had enough extra signals to
+- consume, up until the time its group was closed. */
+- break;
+- }
+-
+- /* If there is an available signal, don't block.
+- If __g1_start has advanced at all, then we must be in G1
+- by now, perhaps in the process of switching back to an older
+- G2, but in either case we're allowed to consume the available
+- signal and should not block anymore. */
+- if ((int)(signals - lowseq) >= 2)
+- {
+- /* Try to grab a signal. See above for MO. (if we do another loop
+- iteration we need to see the correct value of g1_start) */
+- if (atomic_compare_exchange_weak_acquire (
+- cond->__data.__g_signals + g,
++ while (1)
++ {
++ /* Now wait until a signal is available in our group or it is closed.
++ Acquire MO so that if we observe (signals == lowseq) after group
++ switching in __condvar_quiesce_and_switch_g1, we synchronize with that
++ store and will see the prior update of __g1_start done while switching
++ groups too. */
++ unsigned int signals = atomic_load_acquire (cond->__data.__g_signals + g);
++ uint64_t g1_start = __condvar_load_g1_start_relaxed (cond);
++ unsigned int lowseq = (g1_start & 1) == g ? signals : g1_start & ~1U;
++
++ if (seq < (g1_start >> 1))
++ {
++ /* If the group is closed already,
++ then this waiter originally had enough extra signals to
++ consume, up until the time its group was closed. */
++ break;
++ }
++
++ /* If there is an available signal, don't block.
++ If __g1_start has advanced at all, then we must be in G1
++ by now, perhaps in the process of switching back to an older
++ G2, but in either case we're allowed to consume the available
++ signal and should not block anymore. */
++ if ((int)(signals - lowseq) >= 2)
++ {
++ /* Try to grab a signal. See above for MO. (if we do another loop
++ iteration we need to see the correct value of g1_start) */
++ if (atomic_compare_exchange_weak_acquire (
++ cond->__data.__g_signals + g,
+ &signals, signals - 2))
+- break;
+- else
+- continue;
+- }
+- /* No signals available after spinning, so prepare to block.
+- We first acquire a group reference and use acquire MO for that so
+- that we synchronize with the dummy read-modify-write in
+- __condvar_quiesce_and_switch_g1 if we read from that. In turn,
+- in this case this will make us see the advancement of __g_signals
+- to the upcoming new g1_start that occurs with a concurrent
+- attempt to reuse the group's slot.
+- We use acquire MO for the __g_signals check to make the
+- __g1_start check work (see spinning above).
+- Note that the group reference acquisition will not mask the
+- release MO when decrementing the reference count because we use
+- an atomic read-modify-write operation and thus extend the release
+- sequence. */
+- atomic_fetch_add_acquire (cond->__data.__g_refs + g, 2);
+-
+- // Now block.
+- struct _pthread_cleanup_buffer buffer;
+- struct _condvar_cleanup_buffer cbuffer;
+- cbuffer.wseq = wseq;
+- cbuffer.cond = cond;
+- cbuffer.mutex = mutex;
+- cbuffer.private = private;
+- __pthread_cleanup_push (&buffer, __condvar_cleanup_waiting, &cbuffer);
+-
+- err = __futex_abstimed_wait_cancelable64 (
+- cond->__data.__g_signals + g, signals, clockid, abstime, private);
+-
+- __pthread_cleanup_pop (&buffer, 0);
+-
+- if (__glibc_unlikely (err == ETIMEDOUT || err == EOVERFLOW))
+- {
+- __condvar_dec_grefs (cond, g, private);
+- /* If we timed out, we effectively cancel waiting. Note that
+- we have decremented __g_refs before cancellation, so that a
+- deadlock between waiting for quiescence of our group in
+- __condvar_quiesce_and_switch_g1 and us trying to acquire
+- the lock during cancellation is not possible. */
+- __condvar_cancel_waiting (cond, seq, g, private);
+- result = err;
+ break;
+- }
+- else
+- __condvar_dec_grefs (cond, g, private);
+-
++ else
++ continue;
+ }
++ // Now block.
++ struct _pthread_cleanup_buffer buffer;
++ struct _condvar_cleanup_buffer cbuffer;
++ cbuffer.wseq = wseq;
++ cbuffer.cond = cond;
++ cbuffer.mutex = mutex;
++ cbuffer.private = private;
++ __pthread_cleanup_push (&buffer, __condvar_cleanup_waiting, &cbuffer);
++
++ err = __futex_abstimed_wait_cancelable64 (
++ cond->__data.__g_signals + g, signals, clockid, abstime, private);
++
++ __pthread_cleanup_pop (&buffer, 0);
++
++ if (__glibc_unlikely (err == ETIMEDOUT || err == EOVERFLOW))
++ {
++ /* If we timed out, we effectively cancel waiting. */
++ __condvar_cancel_waiting (cond, seq, g, private);
++ result = err;
++ break;
++ }
++ }
+
+ /* Confirm that we have been woken. We do that before acquiring the mutex
+ to allow for execution of pthread_cond_destroy while having acquired the
+--
+2.49.0
+
projects / thirdparty / openembedded / openembedded-core-contrib.git / commitdiff
