4 files changed, 38 insertions, 24 deletions

diff --git a/fs/fuse/Kconfig b/fs/fuse/Kconfig
index 0cf160a94eda..1b2f6c2c3aaf 100644
--- a/fs/fuse/Kconfig
+++ b/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.
diff --git a/fs/fuse/cuse.c b/fs/fuse/cuse.c
index ee8d55042298..e397b675b029 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)
@@ -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 @@ out:
 
 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)
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index c16335315e5d..e83351aa5bad 100644
--- a/fs/fuse/dev.c
+++ b/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
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index e21d4d8f87e3..f3ab824fa302 100644
--- a/fs/fuse/file.c
+++ b/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,