Merge tag 'block-ioctl-cleanup-5.6' into 5.6/scsi-queue

Pull compat_ioctl cleanup from Arnd. Here's his description:

This series concludes the work I did for linux-5.5 on the compat_ioctl()
cleanup, killing off fs/compat_ioctl.c and block/compat_ioctl.c by moving
everything into drivers.

Overall this would be a reduction both in complexity and line count, but
as I'm also adding documentation the overall number of lines increases
in the end.

My plan was originally to keep the SCSI and block parts separate.
This did not work easily because of interdependencies: I cannot
do the final SCSI cleanup in a good way without first addressing the
CDROM ioctls, so this is one series that I hope could be merged through
either the block or the scsi git trees, or possibly both if you can
pull in the same branch.

The series comes in these steps:

1. clean up the sg v3 interface as suggested by Linus. I have
   talked about this with Doug Gilbert as well, and he would
   rebase his sg v4 patches on top of "compat: scsi: sg: fix v3
   compat read/write interface"

2. Actually moving handlers out of block/compat_ioctl.c and
   block/scsi_ioctl.c into drivers, mixed in with cleanup
   patches

3. Document how to do this right. I keep getting asked about this,
   and it helps to point to some documentation file.

The branch is based on another one that fixes a couple of bugs found
during the creation of this series.

Changes since v3:
  https://lore.kernel.org/lkml/20200102145552.1853992-1-arnd@arndb.de/

- Move sr_compat_ioctl fixup to correct patch (Ben Hutchings)
- Add Reviewed-by tags

Changes since v2:
  https://lore.kernel.org/lkml/20191217221708.3730997-1-arnd@arndb.de/

- Rebase to v5.5-rc4, which contains the earlier bugfixes
- Fix sr_block_compat_ioctl() error handling bug found by
  Ben Hutchings
- Fix idecd_locked_compat_ioctl() compat_ptr() bug
- Don't try to handle HDIO_DRIVE_TASKFILE in drivers/ide
- More documentation improvements

Changes since v1:
  https://lore.kernel.org/lkml/20191211204306.1207817-1-arnd@arndb.de/

- move out the bugfixes into a branch for itself
- clean up scsi sg driver further as suggested by Christoph Hellwig
- avoid some ifdefs by moving compat_ptr() out of asm/compat.h
- split out the blkdev_compat_ptr_ioctl function; bug spotted by
  Ben Hutchings
- Improve formatting of documentation

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

2 files changed, 31 insertions, 0 deletions

diff --git a/include/scsi/scsi_ioctl.h b/include/scsi/scsi_ioctl.h
index 5101e987c0ef..4fe69d863b5d 100644
--- a/include/scsi/scsi_ioctl.h
+++ b/include/scsi/scsi_ioctl.h
@@ -44,6 +44,7 @@ typedef struct scsi_fctargaddress {
 int scsi_ioctl_block_when_processing_errors(struct scsi_device *sdev,
 		int cmd, bool ndelay);
 extern int scsi_ioctl(struct scsi_device *, int, void __user *);
+extern int scsi_compat_ioctl(struct scsi_device *sdev, int cmd, void __user *arg);
 
 #endif /* __KERNEL__ */
 #endif /* _SCSI_IOCTL_H */
diff --git a/include/scsi/sg.h b/include/scsi/sg.h
index f91bcca604e4..29c7ad04d2e2 100644
--- a/include/scsi/sg.h
+++ b/include/scsi/sg.h
@@ -68,6 +68,36 @@ typedef struct sg_io_hdr
     unsigned int info;          /* [o] auxiliary information */
 } sg_io_hdr_t;  /* 64 bytes long (on i386) */
 
+#if defined(__KERNEL__)
+#include <linux/compat.h>
+
+struct compat_sg_io_hdr {
+	compat_int_t interface_id;	/* [i] 'S' for SCSI generic (required) */
+	compat_int_t dxfer_direction;	/* [i] data transfer direction  */
+	unsigned char cmd_len;		/* [i] SCSI command length ( <= 16 bytes) */
+	unsigned char mx_sb_len;	/* [i] max length to write to sbp */
+	unsigned short iovec_count;	/* [i] 0 implies no scatter gather */
+	compat_uint_t dxfer_len;	/* [i] byte count of data transfer */
+	compat_uint_t dxferp;		/* [i], [*io] points to data transfer memory
+						or scatter gather list */
+	compat_uptr_t cmdp;		/* [i], [*i] points to command to perform */
+	compat_uptr_t sbp;		/* [i], [*o] points to sense_buffer memory */
+	compat_uint_t timeout;		/* [i] MAX_UINT->no timeout (unit: millisec) */
+	compat_uint_t flags;		/* [i] 0 -> default, see SG_FLAG... */
+	compat_int_t pack_id;		/* [i->o] unused internally (normally) */
+	compat_uptr_t usr_ptr;		/* [i->o] unused internally */
+	unsigned char status;		/* [o] scsi status */
+	unsigned char masked_status;	/* [o] shifted, masked scsi status */
+	unsigned char msg_status;	/* [o] messaging level data (optional) */
+	unsigned char sb_len_wr;	/* [o] byte count actually written to sbp */
+	unsigned short host_status;	/* [o] errors from host adapter */
+	unsigned short driver_status;	/* [o] errors from software driver */
+	compat_int_t resid;		/* [o] dxfer_len - actual_transferred */
+	compat_uint_t duration;		/* [o] time taken by cmd (unit: millisec) */
+	compat_uint_t info;		/* [o] auxiliary information */
+};
+#endif
+
 #define SG_INTERFACE_ID_ORIG 'S'
 
 /* Use negative values to flag difference from original sg_header structure */