* Re: [patch 5/11] s390: #ifdefs in compat_ioctls.
2005-06-01 18:11 ` Christoph Hellwig
@ 2005-06-01 22:43 ` Arnd Bergmann
0 siblings, 0 replies; 3+ messages in thread
From: Arnd Bergmann @ 2005-06-01 22:43 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: Martin Schwidefsky, akpm, linux-kernel, Andi Kleen
On Middeweken 01 Juni 2005 20:11, Christoph Hellwig wrote:
> Actually is there any chance you could just provide ->compat_ioctl handlers
> in the drivers? All these ioctls are specific to drivers, and it sounds like
> a rather bad idea to pollute the global has table with them. This is also
> a good chance to switch the drivers to drop BKL usage in the ioctl path and
> use the same handler for ->unlocked_ioctl and ->compat_ioctl.
I just checked and found that block_device_operations don't support
unlocked_ioctl() yet. I have hacked up a patch to add that without
changing the semantics of blkdev_ioctl(). I have not done thorough
testing, but my system is running fine with this applied.
Does it look ok to you?
[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>
--
Index: drivers/block/ioctl.c
===================================================================
--- 3ac19ebb77c3cd8a1df31b7170c6eaf9e1afb1a4/drivers/block/ioctl.c (mode:100644)
+++ uncommitted/drivers/block/ioctl.c (mode:100644)
@@ -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.
Index: fs/block_dev.c
===================================================================
--- 3ac19ebb77c3cd8a1df31b7170c6eaf9e1afb1a4/fs/block_dev.c (mode:100644)
+++ uncommitted/fs/block_dev.c (mode:100644)
@@ -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
Index: include/linux/fs.h
===================================================================
--- 3ac19ebb77c3cd8a1df31b7170c6eaf9e1afb1a4/include/linux/fs.h (mode:100644)
+++ uncommitted/include/linux/fs.h (mode:100644)
@@ -883,6 +883,7 @@
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 *);
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