[PATCH RT 1/2] locking/rwsem-rt: Remove might_sleep() in __up_read()

From: zanussi
Date: Thu Sep 02 2021 - 16:26:38 EST

From: Andrew Halaney <ahalaney@xxxxxxxxxx>

v5.4.143-rt64-rc1 stable review patch.
If anyone has any objections, please let me know.


[ Upstream commit b2ed0a4302faf2bb09e97529dd274233c082689b ]

There's no chance of sleeping here, the reader is giving up the
lock and possibly waking up the writer who is waiting on it.

Reported-by: Chunyu Hu <chuhu@xxxxxxxxxx>
Signed-off-by: Andrew Halaney <ahalaney@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Signed-off-by: Tom Zanussi <zanussi@xxxxxxxxxx>
kernel/locking/rwsem-rt.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/kernel/locking/rwsem-rt.c b/kernel/locking/rwsem-rt.c
index 19ea20be3fd7..966946454ced 100644
--- a/kernel/locking/rwsem-rt.c
+++ b/kernel/locking/rwsem-rt.c
@@ -200,7 +200,6 @@ void __up_read(struct rw_semaphore *sem)
if (!atomic_dec_and_test(&sem->readers))

- might_sleep();
* Wake the writer, i.e. the rtmutex owner. It might release the