Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

Pull fuse fixes from Miklos Szeredi:
 "This contain a bugfix for CUSE and miscellaneous small fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: remove unused variable in fuse_try_move_page()
  fuse: make fuse_file_fallocate() static
  fuse: Move CUSE Kconfig entry from fs/Kconfig into fs/fuse/Kconfig
  cuse: fix uninitialized variable warnings
  cuse: do not register multiple devices with identical names
  cuse: use mutex as registration lock instead of spinlocks

fs/Kconfig

@@ -68,16 +68,6 @@ source "fs/quota/Kconfig"
 source "fs/autofs4/Kconfig"
 source "fs/fuse/Kconfig"
 
-config CUSE
-	tristate "Character device in Userspace support"
-	depends on FUSE_FS
-	help
-	  This FUSE extension allows character devices to be
-	  implemented in userspace.
-
-	  If you want to develop or use userspace character device
-	  based on CUSE, answer Y or M.
-
 config GENERIC_ACL
 	bool
 	select FS_POSIX_ACL

fs/fuse/Kconfig

@@ -4,12 +4,24 @@ config FUSE_FS
 	  With FUSE it is possible to implement a fully functional filesystem
 	  in a userspace program.
 
-	  There's also companion library: libfuse.  This library along with
-	  utilities is available from the FUSE homepage:
+	  There's also a companion library: libfuse2.  This library is available
+	  from the FUSE homepage:
 	  <http://fuse.sourceforge.net/>
+	  although chances are your distribution already has that library
+	  installed if you've installed the "fuse" package itself.
 
 	  See <file:Documentation/filesystems/fuse.txt> for more information.
 	  See <file:Documentation/Changes> for needed library/utility version.
 
 	  If you want to develop a userspace FS, or if you want to use
 	  a filesystem based on FUSE, answer Y or M.
+
+config CUSE
+	tristate "Character device in Userspace support"
+	depends on FUSE_FS
+	help
+	  This FUSE extension allows character devices to be
+	  implemented in userspace.
+
+	  If you want to develop or use a userspace character device
+	  based on CUSE, answer Y or M.

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)
@@ -267,7 +266,7 @@ static int cuse_parse_one(char **pp, char *end, char **keyp, char **valp)
 static int cuse_parse_devinfo(char *p, size_t len, struct cuse_devinfo *devinfo)
 {
 	char *end = p + len;
-	char *key, *val;
+	char *uninitialized_var(key), *uninitialized_var(val);
 	int rc;
 
 	while (true) {
@@ -305,14 +304,14 @@ static void cuse_gendev_release(struct device *dev)
  */
 static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 {
-	struct cuse_conn *cc = fc_to_cc(fc);
+	struct cuse_conn *cc = fc_to_cc(fc), *pos;
 	struct cuse_init_out *arg = req->out.args[0].value;
 	struct page *page = req->pages[0];
 	struct cuse_devinfo devinfo = { };
 	struct device *dev;
 	struct cdev *cdev;
 	dev_t devt;
-	int rc;
+	int rc, i;
 
 	if (req->out.h.error ||
 	    arg->major != FUSE_KERNEL_VERSION || arg->minor < 11) {
@@ -356,15 +355,24 @@ static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 	dev_set_drvdata(dev, cc);
 	dev_set_name(dev, "%s", devinfo.name);
 
+	mutex_lock(&cuse_lock);
+
+	/* make sure the device-name is unique */
+	for (i = 0; i < CUSE_CONNTBL_LEN; ++i) {
+		list_for_each_entry(pos, &cuse_conntbl[i], list)
+			if (!strcmp(dev_name(pos->dev), dev_name(dev)))
+				goto err_unlock;
+	}
+
 	rc = device_add(dev);
 	if (rc)
-		goto err_device;
+		goto err_unlock;
 
 	/* register cdev */
 	rc = -ENOMEM;
 	cdev = cdev_alloc();
 	if (!cdev)
-		goto err_device;
+		goto err_unlock;
 
 	cdev->owner = THIS_MODULE;
 	cdev->ops = &cuse_frontend_fops;
@@ -377,9 +385,8 @@ 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);
 	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);
@@ -391,7 +398,8 @@ static void cuse_process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 
 err_cdev:
 	cdev_del(cdev);
-err_device:
+err_unlock:
+	mutex_unlock(&cuse_lock);
 	put_device(dev);
 err_region:
 	unregister_chrdev_region(devt, 1);
@@ -520,9 +528,9 @@ 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)

fs/fuse/dev.c

@@ -692,8 +692,6 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 	struct page *oldpage = *pagep;
 	struct page *newpage;
 	struct pipe_buffer *buf = cs->pipebufs;
-	struct address_space *mapping;
-	pgoff_t index;
 
 	unlock_request(cs->fc, cs->req);
 	fuse_copy_finish(cs);
@@ -724,9 +722,6 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 	if (fuse_check_page(newpage) != 0)
 		goto out_fallback_unlock;
 
-	mapping = oldpage->mapping;
-	index = oldpage->index;
-
 	/*
 	 * This is a new and locked page, it shouldn't be mapped or
 	 * have any special flags on it

fs/fuse/file.c

@@ -2177,8 +2177,8 @@ fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
 	return ret;
 }
 
-long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
-			    loff_t length)
+static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
+				loff_t length)
 {
 	struct fuse_file *ff = file->private_data;
 	struct fuse_conn *fc = ff->fc;
@@ -2213,7 +2213,6 @@ long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
 
 	return err;
 }
-EXPORT_SYMBOL_GPL(fuse_file_fallocate);
 
 static const struct file_operations fuse_file_operations = {
 	.llseek		= fuse_file_llseek,