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[1/2] locking/rwsem: Add down_write_interruptible

Message ID 20210308205456.1317366-2-zackr@vmware.com (mailing list archive)
State New, archived
Headers show
Series locking/rwsem: Add down_write_interruptible and use it | expand

Commit Message

Zack Rusin March 8, 2021, 8:54 p.m. UTC 
Add an interruptible version of down_write. It's the other
side of the already implemented down_read_interruptible.
It allows drivers which used custom locking code to
support interruptible rw semaphores to switch over
to rwsem.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-kernel@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
---
 include/linux/rwsem.h  |  1 +
 kernel/locking/rwsem.c | 23 +++++++++++++++++++++++
 2 files changed, 24 insertions(+)

Comments

Peter Zijlstra March 9, 2021, 8:49 a.m. UTC | #1 
On Mon, Mar 08, 2021 at 03:54:55PM -0500, Zack Rusin wrote:
> Add an interruptible version of down_write. It's the other
> side of the already implemented down_read_interruptible.
> It allows drivers which used custom locking code to
> support interruptible rw semaphores to switch over
> to rwsem.
> 
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: linux-kernel@vger.kernel.org
> Cc: dri-devel@lists.freedesktop.org

No SoB!

Assuning you actually wrote and and simply forgot to add it, the patch
does look ok, so:

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Zack Rusin March 9, 2021, 3:37 p.m. UTC | #2 
On 3/9/21 3:49 AM, Peter Zijlstra wrote:
> On Mon, Mar 08, 2021 at 03:54:55PM -0500, Zack Rusin wrote:
>> Add an interruptible version of down_write. It's the other
>> side of the already implemented down_read_interruptible.
>> It allows drivers which used custom locking code to
>> support interruptible rw semaphores to switch over
>> to rwsem.
>>
>> Cc: Peter Zijlstra <peterz@infradead.org>
>> Cc: Ingo Molnar <mingo@redhat.com>
>> Cc: Will Deacon <will@kernel.org>
>> Cc: linux-kernel@vger.kernel.org
>> Cc: dri-devel@lists.freedesktop.org
> 
> No SoB!

Ah, sorry, fixed that locally.

> Assuning you actually wrote and and simply forgot to add it, the patch
> does look ok, so:
> 
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

Thank you. I didn't want to bother you with the code in vmwgfx, so I 
only sent it to the lists (it was missing SoB as well):
https://lore.kernel.org/patchwork/patch/1391810/

z
diff mbox series

Patch

diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h
index 4c715be48717..753ae2cb8677 100644
--- a/include/linux/rwsem.h
+++ b/include/linux/rwsem.h
@@ -135,6 +135,7 @@  extern int down_read_trylock(struct rw_semaphore *sem);
  * lock for writing
  */
 extern void down_write(struct rw_semaphore *sem);
+extern int __must_check down_write_interruptible(struct rw_semaphore *sem);
 extern int __must_check down_write_killable(struct rw_semaphore *sem);
 
 /*
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index abba5df50006..0eadd20347de 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -1270,6 +1270,11 @@  static inline void __down_write(struct rw_semaphore *sem)
 	__down_write_common(sem, TASK_UNINTERRUPTIBLE);
 }
 
+static inline int __down_write_interruptible(struct rw_semaphore *sem)
+{
+	return __down_write_common(sem, TASK_INTERRUPTIBLE);
+}
+
 static inline int __down_write_killable(struct rw_semaphore *sem)
 {
 	return __down_write_common(sem, TASK_KILLABLE);
@@ -1408,6 +1413,24 @@  void __sched down_write(struct rw_semaphore *sem)
 }
 EXPORT_SYMBOL(down_write);
 
+/*
+ * interruptible lock for writing
+ */
+int __sched down_write_interruptible(struct rw_semaphore *sem)
+{
+	might_sleep();
+	rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
+
+	if (LOCK_CONTENDED_RETURN(sem, __down_write_trylock,
+				  __down_write_interruptible)) {
+		rwsem_release(&sem->dep_map, _RET_IP_);
+		return -EINTR;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(down_write_interruptible);
+
 /*
  * lock for writing
  */