[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 4b595904cef..b89c956e04f 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;