This is a note to let you know that I've just added the patch titled
dax/bus.c: use the right locking mode (read vs write) in size_show
to the 6.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dax-bus.c-use-the-right-locking-mode-read-vs-write-i.patch
and it can be found in the queue-6.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 2eda4622187bf637375c484dfe4ebc870298c108
Author: Vishal Verma <vishal.l.verma@xxxxxxxxx>
Date: Tue Apr 30 11:44:26 2024 -0600
dax/bus.c: use the right locking mode (read vs write) in size_show
[ Upstream commit 2acf04532d6d655d8c3b2ee4ddeb320107043086 ]
In size_show(), the dax_dev_rwsem only needs a read lock, but was
acquiring a write lock. Change it to down_read_interruptible() so it
doesn't unnecessarily hold a write lock.
Link: https://lkml.kernel.org/r/20240430-vv-dax_abi_fixes-v3-4-e3dcd755774c@xxxxxxxxx
Fixes: c05ae9d85b47 ("dax/bus.c: replace driver-core lock usage by a local rwsem")
Signed-off-by: Vishal Verma <vishal.l.verma@xxxxxxxxx>
Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Alison Schofield <alison.schofield@xxxxxxxxx>
Cc: Dave Jiang <dave.jiang@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index 0011a6e6a8f2a..f24b67c64d5ec 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -937,11 +937,11 @@ static ssize_t size_show(struct device *dev,
unsigned long long size;
int rc;
- rc = down_write_killable(&dax_dev_rwsem);
+ rc = down_read_interruptible(&dax_dev_rwsem);
if (rc)
return rc;
size = dev_dax_size(dev_dax);
- up_write(&dax_dev_rwsem);
+ up_read(&dax_dev_rwsem);
return sysfs_emit(buf, "%llu\n", size);
}
