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compat_ioctl: move tape handling into drivers

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MTIOCPOS and MTIOCGET are incompatible between 32-bit and 64-bit user
space, and traditionally have been translated in fs/compat_ioctl.c.

To get rid of that translation handler, move a corresponding
implementation into each of the four drivers implementing those commands.

The interesting part of that is now in a new linux/mtio.h header that
wraps the existing uapi/linux/mtio.h header and provides an abstraction
to let drivers handle both cases easily. Using an in_compat_syscall()
check, the caller does not have to keep track of whether this was
called through .unlocked_ioctl() or .compat_ioctl().

Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "Kai Mäkisara" <Kai.Makisara@kolumbus.fi>
Cc: linux-scsi@vger.kernel.org
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Arnd Bergmann
2018-09-07 16:49:43 +02:00
parent 01b8bca81e
commit 1207045da5
5 changed files with 114 additions and 115 deletions
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27
drivers/ide/ide-tape.c
View File

@@ -19,6 +19,7 @@
#define IDETAPE_VERSION "1.20"
#include <linux/compat.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
@@ -1407,14 +1408,10 @@ static long do_idetape_chrdev_ioctl(struct file *file,
if (tape->drv_write_prot)
mtget.mt_gstat |= GMT_WR_PROT(0xffffffff);
if (copy_to_user(argp, &mtget, sizeof(struct mtget)))
return -EFAULT;
return 0;
return put_user_mtget(argp, &mtget);
case MTIOCPOS:
mtpos.mt_blkno = position / tape->user_bs_factor - block_offset;
if (copy_to_user(argp, &mtpos, sizeof(struct mtpos)))
return -EFAULT;
return 0;
return put_user_mtpos(argp, &mtpos);
default:
if (tape->chrdev_dir == IDETAPE_DIR_READ)
ide_tape_discard_merge_buffer(drive, 1);
@@ -1432,6 +1429,22 @@ static long idetape_chrdev_ioctl(struct file *file,
return ret;
}
static long idetape_chrdev_compat_ioctl(struct file *file,
unsigned int cmd, unsigned long arg)
{
long ret;
if (cmd == MTIOCPOS32)
cmd = MTIOCPOS;
else if (cmd == MTIOCGET32)
cmd = MTIOCGET;
mutex_lock(&ide_tape_mutex);
ret = do_idetape_chrdev_ioctl(file, cmd, arg);
mutex_unlock(&ide_tape_mutex);
return ret;
}
/*
* Do a mode sense page 0 with block descriptor and if it succeeds set the tape
* block size with the reported value.
@@ -1886,6 +1899,8 @@ static const struct file_operations idetape_fops = {
.read = idetape_chrdev_read,
.write = idetape_chrdev_write,
.unlocked_ioctl = idetape_chrdev_ioctl,
.compat_ioctl = IS_ENABLED(CONFIG_COMPAT) ?
idetape_chrdev_compat_ioctl : NULL,
.open = idetape_chrdev_open,
.release = idetape_chrdev_release,
.llseek = noop_llseek,