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1207045da5
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>
61 lines
1.3 KiB
C
61 lines
1.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_MTIO_COMPAT_H
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#define _LINUX_MTIO_COMPAT_H
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#include <linux/compat.h>
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#include <uapi/linux/mtio.h>
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#include <linux/uaccess.h>
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/*
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* helper functions for implementing compat ioctls on the four tape
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* drivers: we define the 32-bit layout of each incompatible structure,
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* plus a wrapper function to copy it to user space in either format.
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*/
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struct mtget32 {
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s32 mt_type;
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s32 mt_resid;
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s32 mt_dsreg;
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s32 mt_gstat;
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s32 mt_erreg;
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s32 mt_fileno;
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s32 mt_blkno;
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};
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#define MTIOCGET32 _IOR('m', 2, struct mtget32)
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struct mtpos32 {
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s32 mt_blkno;
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};
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#define MTIOCPOS32 _IOR('m', 3, struct mtpos32)
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static inline int put_user_mtget(void __user *u, struct mtget *k)
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{
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struct mtget32 k32 = {
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.mt_type = k->mt_type,
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.mt_resid = k->mt_resid,
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.mt_dsreg = k->mt_dsreg,
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.mt_gstat = k->mt_gstat,
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.mt_erreg = k->mt_erreg,
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.mt_fileno = k->mt_fileno,
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.mt_blkno = k->mt_blkno,
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};
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int ret;
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if (in_compat_syscall())
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ret = copy_to_user(u, &k32, sizeof(k32));
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else
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ret = copy_to_user(u, k, sizeof(*k));
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return ret ? -EFAULT : 0;
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}
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static inline int put_user_mtpos(void __user *u, struct mtpos *k)
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{
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if (in_compat_syscall())
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return put_user(k->mt_blkno, (u32 __user *)u);
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else
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return put_user(k->mt_blkno, (long __user *)u);
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}
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#endif
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