[PATCH] sanitize blkdev_get() and friends

* get rid of fake struct file/struct dentry in __blkdev_get()
* merge __blkdev_get() and do_open()
* get rid of flags argument of blkdev_get()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 22 insertions, 43 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 4b595904cefd..b89c956e04f6 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -844,9 +844,8 @@ struct block_device *open_by_devnum(dev_t dev, fmode_t mode)
 {
         struct block_device *bdev = bdget(dev);
         int err = -ENOMEM;
-        int flags = mode & FMODE_WRITE ? O_RDWR : O_RDONLY;
         if (bdev)
-                err = blkdev_get(bdev, mode, flags);
+                err = blkdev_get(bdev, mode);
         return err ? ERR_PTR(err) : bdev;
 }
 
@@ -975,8 +974,6 @@ void bd_set_size(struct block_device *bdev, loff_t size)
 }
 EXPORT_SYMBOL(bd_set_size);
 
-static int __blkdev_get(struct block_device *bdev, fmode_t mode, unsigned flags,
-                        int for_part);
 static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
 
 /*
@@ -986,7 +983,7 @@ static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part);
  *    mutex_lock_nested(whole->bd_mutex, 1)
  */
 
-static int do_open(struct block_device *bdev, struct file *file, int for_part)
+static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
 {
         struct gendisk *disk;
         struct hd_struct *part = NULL;
@@ -994,9 +991,9 @@ static int do_open(struct block_device *bdev, struct file *file, int for_part)
         int partno;
         int perm = 0;
 
-        if (file->f_mode & FMODE_READ)
+        if (mode & FMODE_READ)
                 perm |= MAY_READ;
-        if (file->f_mode & FMODE_WRITE)
+        if (mode & FMODE_WRITE)
                 perm |= MAY_WRITE;
         /*
          * hooks: /n/, see "layering violations".
@@ -1007,15 +1004,7 @@ static int do_open(struct block_device *bdev, struct file *file, int for_part)
                 return ret;
         }
 
-        if (file->f_flags & O_NDELAY)
-                file->f_mode |= FMODE_NDELAY;
-        if (file->f_flags & O_EXCL)
-                file->f_mode |= FMODE_EXCL;
-        if ((file->f_flags & O_ACCMODE) == 3)
-                file->f_mode |= FMODE_WRITE_IOCTL;
-
         ret = -ENXIO;
-        file->f_mapping = bdev->bd_inode->i_mapping;
 
         lock_kernel();
 
@@ -1034,7 +1023,7 @@ static int do_open(struct block_device *bdev, struct file *file, int for_part)
                 if (!partno) {
                         struct backing_dev_info *bdi;
                         if (disk->fops->open) {
-                                ret = disk->fops->open(bdev, file->f_mode);
+                                ret = disk->fops->open(bdev, mode);
                                 if (ret)
                                         goto out_clear;
                         }
@@ -1054,7 +1043,7 @@ static int do_open(struct block_device *bdev, struct file *file, int for_part)
                         if (!whole)
                                 goto out_clear;
                         BUG_ON(for_part);
-                        ret = __blkdev_get(whole, file->f_mode, file->f_flags, 1);
+                        ret = __blkdev_get(whole, mode, 1);
                         if (ret)
                                 goto out_clear;
                         bdev->bd_contains = whole;
@@ -1075,7 +1064,7 @@ static int do_open(struct block_device *bdev, struct file *file, int for_part)
                 disk = NULL;
                 if (bdev->bd_contains == bdev) {
                         if (bdev->bd_disk->fops->open) {
-                                ret = bdev->bd_disk->fops->open(bdev, file->f_mode);
+                                ret = bdev->bd_disk->fops->open(bdev, mode);
                                 if (ret)
                                         goto out_unlock_bdev;
                         }
@@ -1095,7 +1084,7 @@ static int do_open(struct block_device *bdev, struct file *file, int for_part)
         bdev->bd_part = NULL;
         bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
         if (bdev != bdev->bd_contains)
-                __blkdev_put(bdev->bd_contains, file->f_mode, 1);
+                __blkdev_put(bdev->bd_contains, mode, 1);
         bdev->bd_contains = NULL;
  out_unlock_bdev:
         mutex_unlock(&bdev->bd_mutex);
@@ -1111,28 +1100,9 @@ static int do_open(struct block_device *bdev, struct file *file, int for_part)
         return ret;
 }
 
-static int __blkdev_get(struct block_device *bdev, fmode_t mode, unsigned flags,
-                        int for_part)
-{
-        /*
-         * This crockload is due to bad choice of ->open() type.
-         * It will go away.
-         * For now, block device ->open() routine must _not_
-         * examine anything in 'inode' argument except ->i_rdev.
-         */
-        struct file fake_file = {};
-        struct dentry fake_dentry = {};
-        fake_file.f_mode = mode;
-        fake_file.f_flags = flags;
-        fake_file.f_path.dentry = &fake_dentry;
-        fake_dentry.d_inode = bdev->bd_inode;
-
-        return do_open(bdev, &fake_file, for_part);
-}
-
-int blkdev_get(struct block_device *bdev, fmode_t mode, unsigned flags)
+int blkdev_get(struct block_device *bdev, fmode_t mode)
 {
-        return __blkdev_get(bdev, mode, flags, 0);
+        return __blkdev_get(bdev, mode, 0);
 }
 EXPORT_SYMBOL(blkdev_get);
 
@@ -1149,15 +1119,24 @@ static int blkdev_open(struct inode * inode, struct file * filp)
          */
         filp->f_flags |= O_LARGEFILE;
 
+        if (filp->f_flags & O_NDELAY)
+                filp->f_mode |= FMODE_NDELAY;
+        if (filp->f_flags & O_EXCL)
+                filp->f_mode |= FMODE_EXCL;
+        if ((filp->f_flags & O_ACCMODE) == 3)
+                filp->f_mode |= FMODE_WRITE_IOCTL;
+
         bdev = bd_acquire(inode);
         if (bdev == NULL)
                 return -ENOMEM;
 
-        res = do_open(bdev, filp, 0);
+        filp->f_mapping = bdev->bd_inode->i_mapping;
+
+        res = blkdev_get(bdev, filp->f_mode);
         if (res)
                 return res;
 
-        if (!(filp->f_flags & O_EXCL) )
+        if (!(filp->f_mode & FMODE_EXCL))
                 return 0;
 
         if (!(res = bd_claim(bdev, filp)))
@@ -1327,7 +1306,7 @@ struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *h
         if (IS_ERR(bdev))
                 return bdev;
 
-        error = blkdev_get(bdev, mode, 0);
+        error = blkdev_get(bdev, mode);
         if (error)
                 return ERR_PTR(error);
         error = -EACCES;