linux/include/scsi/scsi_ioctl.h
Gustavo A. R. Silva 5febf6d6ae scsi: Replace zero-length array with flexible-array member
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare variable-length
types such as these ones is a flexible array member[1][2], introduced in
C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by this
change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Link: https://lore.kernel.org/r/20200224161406.GA21454@embeddedor
Reviewed-by: Lee Duncan <lduncan@suse.com>
Reviewed-by: Satish Kharat <satishkh@cisco.com>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2020-03-11 23:07:56 -04:00

51 lines
1.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _SCSI_IOCTL_H
#define _SCSI_IOCTL_H
#define SCSI_IOCTL_SEND_COMMAND 1
#define SCSI_IOCTL_TEST_UNIT_READY 2
#define SCSI_IOCTL_BENCHMARK_COMMAND 3
#define SCSI_IOCTL_SYNC 4 /* Request synchronous parameters */
#define SCSI_IOCTL_START_UNIT 5
#define SCSI_IOCTL_STOP_UNIT 6
/* The door lock/unlock constants are compatible with Sun constants for
the cdrom */
#define SCSI_IOCTL_DOORLOCK 0x5380 /* lock the eject mechanism */
#define SCSI_IOCTL_DOORUNLOCK 0x5381 /* unlock the mechanism */
#define SCSI_REMOVAL_PREVENT 1
#define SCSI_REMOVAL_ALLOW 0
#ifdef __KERNEL__
struct scsi_device;
/*
* Structures used for scsi_ioctl et al.
*/
typedef struct scsi_ioctl_command {
unsigned int inlen;
unsigned int outlen;
unsigned char data[];
} Scsi_Ioctl_Command;
typedef struct scsi_idlun {
__u32 dev_id;
__u32 host_unique_id;
} Scsi_Idlun;
/* Fibre Channel WWN, port_id struct */
typedef struct scsi_fctargaddress {
__u32 host_port_id;
unsigned char host_wwn[8]; // include NULL term.
} 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 */