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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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28
drivers/scsi/st.c
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@@ -22,6 +22,7 @@ static const char *verstr = "20160209";
#include <linux/module.h>
#include <linux/compat.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/sched/signal.h>
@@ -3800,14 +3801,11 @@ static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
if (STp->cleaning_req)
mt_status.mt_gstat |= GMT_CLN(0xffffffff);
i = copy_to_user(p, &mt_status, sizeof(struct mtget));
if (i) {
retval = (-EFAULT);
retval = put_user_mtget(p, &mt_status);
if (retval)
goto out;
}
STp->recover_reg = 0; /* Clear after read */
retval = 0;
goto out;
} /* End of MTIOCGET */
if (cmd_type == _IOC_TYPE(MTIOCPOS) && cmd_nr == _IOC_NR(MTIOCPOS)) {
@@ -3821,9 +3819,7 @@ static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
goto out;
}
mt_pos.mt_blkno = blk;
i = copy_to_user(p, &mt_pos, sizeof(struct mtpos));
if (i)
retval = (-EFAULT);
retval = put_user_mtpos(p, &mt_pos);
goto out;
}
mutex_unlock(&STp->lock);
@@ -3857,14 +3853,26 @@ static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
}
#ifdef CONFIG_COMPAT
static long st_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
static long st_compat_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
{
void __user *p = compat_ptr(arg);
struct scsi_tape *STp = file->private_data;
struct scsi_device *sdev = STp->device;
int ret = -ENOIOCTLCMD;
/* argument conversion is handled using put_user_mtpos/put_user_mtget */
switch (cmd_in) {
case MTIOCTOP:
return st_ioctl(file, MTIOCTOP, (unsigned long)p);
case MTIOCPOS32:
return st_ioctl(file, MTIOCPOS, (unsigned long)p);
case MTIOCGET32:
return st_ioctl(file, MTIOCGET, (unsigned long)p);
}
if (sdev->host->hostt->compat_ioctl) {
ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);
ret = sdev->host->hostt->compat_ioctl(sdev, cmd_in, (void __user *)arg);
}
return ret;