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dax/bus.c: use the right locking mode (read vs write) in size_show

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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@intel.com
Fixes: c05ae9d85b ("dax/bus.c: replace driver-core lock usage by a local rwsem")
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: Alison Schofield <alison.schofield@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Vishal Verma 2024-04-30 11:44:26 -06:00 committed by Andrew Morton
parent e39dbcfba7
commit 2acf04532d
1 changed files with 2 additions and 2 deletions
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4
drivers/dax/bus.c
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@ -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);
}