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authorDavid Herrmann <dh.herrmann@googlemail.com>2012-11-17 12:45:47 +0100
committerMiklos Szeredi <mszeredi@suse.cz>2013-01-17 13:04:51 +0100
commit8ce03fd76d323526a693d05d85296ef07a387a9f (patch)
treeb1370c17b55e60dfc8faa8b6a8dae2b394199ce9 /fs/fuse
parentdfdebc24837ed0a1d6ad73b108a10d3c88d1b6e8 (diff)
downloadlinux-8ce03fd76d323526a693d05d85296ef07a387a9f.tar.gz
cuse: use mutex as registration lock instead of spinlocks
We need to check for name-collisions during cuse-device registration. To avoid race-conditions, this needs to be protected during the whole device registration. Therefore, replace the spinlocks by mutexes first so we can safely extend the locked regions to include more expensive or sleeping code paths. Signed-off-by: David Herrmann <dh.herrmann@googlemail.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Diffstat (limited to 'fs/fuse')
-rw-r--r--fs/fuse/cuse.c15
1 files changed, 7 insertions, 8 deletions
diff --git a/fs/fuse/cuse.c b/fs/fuse/cuse.c
index ee8d5504229..048e89f2508 100644
--- a/fs/fuse/cuse.c
+++ b/fs/fuse/cuse.c
@@ -45,7 +45,6 @@
#include <linux/miscdevice.h>
#include <linux/mutex.h>
#include <linux/slab.h>
-#include <linux/spinlock.h>
#include <linux/stat.h>
#include <linux/module.h>
@@ -63,7 +62,7 @@ struct cuse_conn {
bool unrestricted_ioctl;
};
-static DEFINE_SPINLOCK(cuse_lock); /* protects cuse_conntbl */
+static DEFINE_MUTEX(cuse_lock); /* protects registration */
static struct list_head cuse_conntbl[CUSE_CONNTBL_LEN];
static struct class *cuse_class;
@@ -114,14 +113,14 @@ static int cuse_open(struct inode *inode, struct file *file)
int rc;
/* look up and get the connection */
- spin_lock(&cuse_lock);
+ mutex_lock(&cuse_lock);
list_for_each_entry(pos, cuse_conntbl_head(devt), list)
if (pos->dev->devt == devt) {
fuse_conn_get(&pos->fc);
cc = pos;
break;
}
- spin_unlock(&cuse_lock);
+ mutex_unlock(&cuse_lock);
/* dead? */
if (!cc)
@@ -377,9 +376,9 @@ static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
cc->cdev = cdev;
/* make the device available */
- spin_lock(&cuse_lock);
+ mutex_lock(&cuse_lock);
list_add(&cc->list, cuse_conntbl_head(devt));
- spin_unlock(&cuse_lock);
+ mutex_unlock(&cuse_lock);
/* announce device availability */
dev_set_uevent_suppress(dev, 0);
@@ -520,9 +519,9 @@ static int cuse_channel_release(struct inode *inode, struct file *file)
int rc;
/* remove from the conntbl, no more access from this point on */
- spin_lock(&cuse_lock);
+ mutex_lock(&cuse_lock);
list_del_init(&cc->list);
- spin_unlock(&cuse_lock);
+ mutex_unlock(&cuse_lock);
/* remove device */
if (cc->dev)