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devtmpfs: Convert dirlock to a mutex 

devtmpfs has a rw_lock dirlock which serializes delete_path and
create_path.

This code was obviously never tested with the usual set of debugging
facilities enabled. In the dirlock held sections the code calls:

 - vfs functions which take mutexes
 - kmalloc(, GFP_KERNEL)

In both code pathes the might sleep warning triggers and spams dmesg.

Convert the rw_lock to a mutex. There is no reason why this needs to
be a rwlock.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
hifive-unleashed-5.1
Thomas Gleixner 2009-12-16 21:31:33 +00:00 committed by Greg Kroah-Hartman
parent f42ecb2808
commit f1f76f865b
1 changed files with 5 additions and 7 deletions
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12
drivers/base/devtmpfs.c
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@ -32,7 +32,7 @@ static int dev_mount = 1;
static int dev_mount;
#endif
static rwlock_t dirlock;
static DEFINE_MUTEX(dirlock);
static int __init mount_param(char *str)
{
@ -93,7 +93,7 @@ static int create_path(const char *nodepath)
{
int err;
read_lock(&dirlock);
mutex_lock(&dirlock);
err = dev_mkdir(nodepath, 0755);
if (err == -ENOENT) {
char *path;
@ -117,7 +117,7 @@ static int create_path(const char *nodepath)
}
kfree(path);
}
read_unlock(&dirlock);
mutex_unlock(&dirlock);
return err;
}
@ -229,7 +229,7 @@ static int delete_path(const char *nodepath)
if (!path)
return -ENOMEM;
write_lock(&dirlock);
mutex_lock(&dirlock);
for (;;) {
char *base;
@ -241,7 +241,7 @@ static int delete_path(const char *nodepath)
if (err)
break;
}
write_unlock(&dirlock);
mutex_unlock(&dirlock);
kfree(path);
return err;
@ -352,8 +352,6 @@ int __init devtmpfs_init(void)
int err;
struct vfsmount *mnt;
rwlock_init(&dirlock);
err = register_filesystem(&dev_fs_type);
if (err) {
printk(KERN_ERR "devtmpfs: unable to register devtmpfs "