[PATCH] block: add unlocked_ioctl support for block devices

This patch allows block device drivers to convert their ioctl functions to unlocked_ioctl() like character devices and other subsystems. All functions that were called with the BKL held before are still used that way, but I would not be surprised if it could be removed from the ioctl functions in drivers/block/ioctl.c themselves. As a side note, I found that compat_blkdev_ioctl() acquires the BKL as well, which looks like a bug. I have checked that every user of disk->fops->compat_ioctl() in the current git tree gets the BKL itself, so it could easily be removed from compat_blkdev_ioctl(). Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] block: add unlocked_ioctl support for block devices
This patch allows block device drivers to convert their ioctl functions to unlocked_ioctl() like character devices and other subsystems. All functions that were called with the BKL held before are still used that way, but I would not be surprised if it could be removed from the ioctl functions in drivers/block/ioctl.c themselves. As a side note, I found that compat_blkdev_ioctl() acquires the BKL as well, which looks like a bug. I have checked that every user of disk->fops->compat_ioctl() in the current git tree gets the BKL itself, so it could easily be removed from compat_blkdev_ioctl(). Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Arnd Bergmann · Linus Torvalds
1 parent 0d77e5a2c2
Showing 3 changed files with 57 additions and 23 deletions Side-by-side Diff
drivers/block/ioctl.c
fs/block_dev.c
include/linux/fs.h
@@ -133,11 +133,9 @@
 	return put_user(val, (u64 __user *)arg);
 }
  
-int blkdev_ioctl(struct inode *inode, struct file *file, unsigned cmd,
-			unsigned long arg)
+static int blkdev_locked_ioctl(struct file *file, struct block_device *bdev,
+				unsigned cmd, unsigned long arg)
 {
-	struct block_device *bdev = inode->i_bdev;
-	struct gendisk *disk = bdev->bd_disk;
 	struct backing_dev_info *bdi;
 	int ret, n;
  
  
  
  
  
  
  
  
  
@@ -190,36 +188,72 @@
 		return put_ulong(arg, bdev->bd_inode->i_size >> 9);
 	case BLKGETSIZE64:
 		return put_u64(arg, bdev->bd_inode->i_size);
+	}
+	return -ENOIOCTLCMD;
+}
+
+static int blkdev_driver_ioctl(struct inode *inode, struct file *file,
+		struct gendisk *disk, unsigned cmd, unsigned long arg)
+{
+	int ret;
+	if (disk->fops->unlocked_ioctl)
+		return disk->fops->unlocked_ioctl(file, cmd, arg);
+
+	if (disk->fops->ioctl) {
+		lock_kernel();
+		ret = disk->fops->ioctl(inode, file, cmd, arg);
+		unlock_kernel();
+		return ret;
+	}
+
+	return -ENOTTY;
+}
+
+int blkdev_ioctl(struct inode *inode, struct file *file, unsigned cmd,
+			unsigned long arg)
+{
+	struct block_device *bdev = inode->i_bdev;
+	struct gendisk *disk = bdev->bd_disk;
+	int ret, n;
+
+	switch(cmd) {
 	case BLKFLSBUF:
 		if (!capable(CAP_SYS_ADMIN))
 			return -EACCES;
-		if (disk->fops->ioctl) {
-			ret = disk->fops->ioctl(inode, file, cmd, arg);
-			/* -EINVAL to handle old uncorrected drivers */
-			if (ret != -EINVAL && ret != -ENOTTY)
-				return ret;
-		}
+
+		ret = blkdev_driver_ioctl(inode, file, disk, cmd, arg);
+		/* -EINVAL to handle old uncorrected drivers */
+		if (ret != -EINVAL && ret != -ENOTTY)
+			return ret;
+
+		lock_kernel();
 		fsync_bdev(bdev);
 		invalidate_bdev(bdev, 0);
+		unlock_kernel();
 		return 0;
+
 	case BLKROSET:
-		if (disk->fops->ioctl) {
-			ret = disk->fops->ioctl(inode, file, cmd, arg);
-			/* -EINVAL to handle old uncorrected drivers */
-			if (ret != -EINVAL && ret != -ENOTTY)
-				return ret;
-		}
+		ret = blkdev_driver_ioctl(inode, file, disk, cmd, arg);
+		/* -EINVAL to handle old uncorrected drivers */
+		if (ret != -EINVAL && ret != -ENOTTY)
+			return ret;
 		if (!capable(CAP_SYS_ADMIN))
 			return -EACCES;
 		if (get_user(n, (int __user *)(arg)))
 			return -EFAULT;
+		lock_kernel();
 		set_device_ro(bdev, n);
+		unlock_kernel();
 		return 0;
-	default:
-		if (disk->fops->ioctl)
-			return disk->fops->ioctl(inode, file, cmd, arg);
 	}
-	return -ENOTTY;
+
+	lock_kernel();
+	ret = blkdev_locked_ioctl(file, bdev, cmd, arg);
+	unlock_kernel();
+	if (ret != -ENOIOCTLCMD)
+		return ret;
+
+	return blkdev_driver_ioctl(inode, file, disk, cmd, arg);
 }
  
 /* Most of the generic ioctls are handled in the normal fallback path.
@@ -777,8 +777,7 @@
 	return generic_file_aio_write_nolock(iocb, &local_iov, 1, &iocb->ki_pos);
 }
  
-static int block_ioctl(struct inode *inode, struct file *file, unsigned cmd,
-			unsigned long arg)
+static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
 {
 	return blkdev_ioctl(file->f_mapping->host, file, cmd, arg);
 }
@@ -803,7 +802,7 @@
   	.aio_write	= blkdev_file_aio_write, 
 	.mmap		= generic_file_mmap,
 	.fsync		= block_fsync,
-	.ioctl		= block_ioctl,
+	.unlocked_ioctl	= block_ioctl,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl	= compat_blkdev_ioctl,
 #endif
@@ -884,6 +884,7 @@
 	int (*open) (struct inode *, struct file *);
 	int (*release) (struct inode *, struct file *);
 	int (*ioctl) (struct inode *, struct file *, unsigned, unsigned long);
+	long (*unlocked_ioctl) (struct file *, unsigned, unsigned long);
 	long (*compat_ioctl) (struct file *, unsigned, unsigned long);
 	int (*media_changed) (struct gendisk *);
 	int (*revalidate_disk) (struct gendisk *);
...	...	@@ -133,11 +133,9 @@
133	133	return put_user(val, (u64 __user *)arg);
134	134	}
135	135
136		-int blkdev_ioctl(struct inode inode, struct file file, unsigned cmd,
137		- unsigned long arg)
	136	+static int blkdev_locked_ioctl(struct file file, struct block_device bdev,
	137	+ unsigned cmd, unsigned long arg)
138	138	{
139		- struct block_device *bdev = inode->i_bdev;
140		- struct gendisk *disk = bdev->bd_disk;
141	139	struct backing_dev_info *bdi;
142	140	int ret, n;
143	141
144	142
145	143
146	144
147	145
148	146
149	147
150	148
151	149
...	...	@@ -190,36 +188,72 @@
190	188	return put_ulong(arg, bdev->bd_inode->i_size >> 9);
191	189	case BLKGETSIZE64:
192	190	return put_u64(arg, bdev->bd_inode->i_size);
	191	+ }
	192	+ return -ENOIOCTLCMD;
	193	+}
	194	+
	195	+static int blkdev_driver_ioctl(struct inode inode, struct file file,
	196	+ struct gendisk *disk, unsigned cmd, unsigned long arg)
	197	+{
	198	+ int ret;
	199	+ if (disk->fops->unlocked_ioctl)
	200	+ return disk->fops->unlocked_ioctl(file, cmd, arg);
	201	+
	202	+ if (disk->fops->ioctl) {
	203	+ lock_kernel();
	204	+ ret = disk->fops->ioctl(inode, file, cmd, arg);
	205	+ unlock_kernel();
	206	+ return ret;
	207	+ }
	208	+
	209	+ return -ENOTTY;
	210	+}
	211	+
	212	+int blkdev_ioctl(struct inode inode, struct file file, unsigned cmd,
	213	+ unsigned long arg)
	214	+{
	215	+ struct block_device *bdev = inode->i_bdev;
	216	+ struct gendisk *disk = bdev->bd_disk;
	217	+ int ret, n;
	218	+
	219	+ switch(cmd) {
193	220	case BLKFLSBUF:
194	221	if (!capable(CAP_SYS_ADMIN))
195	222	return -EACCES;
196		- if (disk->fops->ioctl) {
197		- ret = disk->fops->ioctl(inode, file, cmd, arg);
198		- /* -EINVAL to handle old uncorrected drivers */
199		- if (ret != -EINVAL && ret != -ENOTTY)
200		- return ret;
201		- }
	223	+
	224	+ ret = blkdev_driver_ioctl(inode, file, disk, cmd, arg);
	225	+ /* -EINVAL to handle old uncorrected drivers */
	226	+ if (ret != -EINVAL && ret != -ENOTTY)
	227	+ return ret;
	228	+
	229	+ lock_kernel();
202	230	fsync_bdev(bdev);
203	231	invalidate_bdev(bdev, 0);
	232	+ unlock_kernel();
204	233	return 0;
	234	+
205	235	case BLKROSET:
206		- if (disk->fops->ioctl) {
207		- ret = disk->fops->ioctl(inode, file, cmd, arg);
208		- /* -EINVAL to handle old uncorrected drivers */
209		- if (ret != -EINVAL && ret != -ENOTTY)
210		- return ret;
211		- }
	236	+ ret = blkdev_driver_ioctl(inode, file, disk, cmd, arg);
	237	+ /* -EINVAL to handle old uncorrected drivers */
	238	+ if (ret != -EINVAL && ret != -ENOTTY)
	239	+ return ret;
212	240	if (!capable(CAP_SYS_ADMIN))
213	241	return -EACCES;
214	242	if (get_user(n, (int __user *)(arg)))
215	243	return -EFAULT;
	244	+ lock_kernel();
216	245	set_device_ro(bdev, n);
	246	+ unlock_kernel();
217	247	return 0;
218		- default:
219		- if (disk->fops->ioctl)
220		- return disk->fops->ioctl(inode, file, cmd, arg);
221	248	}
222		- return -ENOTTY;
	249	+
	250	+ lock_kernel();
	251	+ ret = blkdev_locked_ioctl(file, bdev, cmd, arg);
	252	+ unlock_kernel();
	253	+ if (ret != -ENOIOCTLCMD)
	254	+ return ret;
	255	+
	256	+ return blkdev_driver_ioctl(inode, file, disk, cmd, arg);
223	257	}
224	258
225	259	/* Most of the generic ioctls are handled in the normal fallback path.
...	...	@@ -777,8 +777,7 @@
777	777	return generic_file_aio_write_nolock(iocb, &local_iov, 1, &iocb->ki_pos);
778	778	}
779	779
780		-static int block_ioctl(struct inode inode, struct file file, unsigned cmd,
781		- unsigned long arg)
	780	+static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
782	781	{
783	782	return blkdev_ioctl(file->f_mapping->host, file, cmd, arg);
784	783	}
...	...	@@ -803,7 +802,7 @@
803	802	.aio_write = blkdev_file_aio_write,
804	803	.mmap = generic_file_mmap,
805	804	.fsync = block_fsync,
806		- .ioctl = block_ioctl,
	805	+ .unlocked_ioctl = block_ioctl,
807	806	#ifdef CONFIG_COMPAT
808	807	.compat_ioctl = compat_blkdev_ioctl,
809	808	#endif
...	...	@@ -884,6 +884,7 @@
884	884	int (open) (struct inode , struct file *);
885	885	int (release) (struct inode , struct file *);
886	886	int (ioctl) (struct inode , struct file *, unsigned, unsigned long);
	887	+ long (unlocked_ioctl) (struct file , unsigned, unsigned long);
887	888	long (compat_ioctl) (struct file , unsigned, unsigned long);
888	889	int (media_changed) (struct gendisk );
889	890	int (revalidate_disk) (struct gendisk );