linux-kernel - [PATCH] locking/rwsem: Remove unnessary check in rwsem_down_read

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Wed,  8 Nov 2023 10:56:39 +0000
From:   Haifeng Xu <haifeng.xu@...pee.com>
To:     longman@...hat.com
Cc:     peterz@...radead.org, mingo@...hat.com, will@...nel.org,
        boqun.feng@...il.com, linux-kernel@...r.kernel.org,
        Haifeng Xu <haifeng.xu@...pee.com>
Subject: [PATCH] locking/rwsem: Remove unnessary check in rwsem_down_read_slowpath()

When the owner of rw_semaphore is reader, the count can't be
RWSEM_WRITER_LOCKED, so there is no need to check it.

Signed-off-by: Haifeng Xu <haifeng.xu@...pee.com>
---
 kernel/locking/rwsem.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index 2340b6d90ec6..7a4d8a9ebd9c 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -1005,8 +1005,7 @@ rwsem_down_read_slowpath(struct rw_semaphore *sem, long count, unsigned int stat
 	 * waiter, don't attempt optimistic lock stealing if the lock is
 	 * currently owned by readers.
 	 */
-	if ((atomic_long_read(&sem->owner) & RWSEM_READER_OWNED) &&
-	    (rcnt > 1) && !(count & RWSEM_WRITER_LOCKED))
+	if ((atomic_long_read(&sem->owner) & RWSEM_READER_OWNED) && (rcnt > 1))
 		goto queue;
 
 	/*
-- 
2.25.1