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linux/drivers/scsi/isci/sas.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

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/*
* This file is provided under a dual BSD/GPLv2 license. When using or
* redistributing this file, you may do so under either license.
*
* GPL LICENSE SUMMARY
*
* Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
* The full GNU General Public License is included in this distribution
* in the file called LICENSE.GPL.
*
* BSD LICENSE
*
* Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _SCI_SAS_H_
#define _SCI_SAS_H_
#include <linux/kernel.h>
/*
* SATA FIS Types These constants depict the various SATA FIS types devined in
* the serial ATA specification.
* XXX: This needs to go into <scsi/sas.h>
*/
#define FIS_REGH2D 0x27
#define FIS_REGD2H 0x34
#define FIS_SETDEVBITS 0xA1
#define FIS_DMA_ACTIVATE 0x39
#define FIS_DMA_SETUP 0x41
#define FIS_BIST_ACTIVATE 0x58
#define FIS_PIO_SETUP 0x5F
#define FIS_DATA 0x46
/**************************************************************************/
#define SSP_RESP_IU_MAX_SIZE 280
/*
* contents of the SSP COMMAND INFORMATION UNIT.
* For specific information on each of these individual fields please
* reference the SAS specification SSP transport layer section.
* XXX: This needs to go into <scsi/sas.h>
*/
struct ssp_cmd_iu {
u8 LUN[8];
u8 add_cdb_len:6;
u8 _r_a:2;
u8 _r_b;
u8 en_fburst:1;
u8 task_prio:4;
u8 task_attr:3;
u8 _r_c;
u8 cdb[16];
} __packed;
/*
* contents of the SSP TASK INFORMATION UNIT.
* For specific information on each of these individual fields please
* reference the SAS specification SSP transport layer section.
* XXX: This needs to go into <scsi/sas.h>
*/
struct ssp_task_iu {
u8 LUN[8];
u8 _r_a;
u8 task_func;
u8 _r_b[4];
u16 task_tag;
u8 _r_c[12];
} __packed;
/*
* struct smp_req_phy_id - This structure defines the contents of
* an SMP Request that is comprised of the struct smp_request_header and a
* phy identifier.
* Examples: SMP_REQUEST_DISCOVER, SMP_REQUEST_REPORT_PHY_SATA.
*
* For specific information on each of these individual fields please reference
* the SAS specification.
*/
struct smp_req_phy_id {
u8 _r_a[4]; /* bytes 4-7 */
u8 ign_zone_grp:1; /* byte 8 */
u8 _r_b:7;
u8 phy_id; /* byte 9 */
u8 _r_c; /* byte 10 */
u8 _r_d; /* byte 11 */
} __packed;
/*
* struct smp_req_config_route_info - This structure defines the
* contents of an SMP Configure Route Information request.
*
* For specific information on each of these individual fields please reference
* the SAS specification.
*/
struct smp_req_conf_rtinfo {
u16 exp_change_cnt; /* bytes 4-5 */
u8 exp_rt_idx_hi; /* byte 6 */
u8 exp_rt_idx; /* byte 7 */
u8 _r_a; /* byte 8 */
u8 phy_id; /* byte 9 */
u16 _r_b; /* bytes 10-11 */
u8 _r_c:7; /* byte 12 */
u8 dis_rt_entry:1;
u8 _r_d[3]; /* bytes 13-15 */
u8 rt_sas_addr[8]; /* bytes 16-23 */
u8 _r_e[16]; /* bytes 24-39 */
} __packed;
/*
* struct smp_req_phycntl - This structure defines the contents of an
* SMP Phy Controller request.
*
* For specific information on each of these individual fields please reference
* the SAS specification.
*/
struct smp_req_phycntl {
u16 exp_change_cnt; /* byte 4-5 */
u8 _r_a[3]; /* bytes 6-8 */
u8 phy_id; /* byte 9 */
u8 phy_op; /* byte 10 */
u8 upd_pathway:1; /* byte 11 */
u8 _r_b:7;
u8 _r_c[12]; /* byte 12-23 */
u8 att_dev_name[8]; /* byte 24-31 */
u8 _r_d:4; /* byte 32 */
u8 min_linkrate:4;
u8 _r_e:4; /* byte 33 */
u8 max_linkrate:4;
u8 _r_f[2]; /* byte 34-35 */
u8 pathway:4; /* byte 36 */
u8 _r_g:4;
u8 _r_h[3]; /* bytes 37-39 */
} __packed;
/*
* struct smp_req - This structure simply unionizes the existing request
* structures into a common request type.
*
* XXX: This data structure may need to go to scsi/sas.h
*/
struct smp_req {
u8 type; /* byte 0 */
u8 func; /* byte 1 */
u8 alloc_resp_len; /* byte 2 */
u8 req_len; /* byte 3 */
u8 req_data[];
} __packed;
/*
* struct sci_sas_address - This structure depicts how a SAS address is
* represented by SCI.
* XXX convert this to u8 [SAS_ADDR_SIZE] like the rest of libsas
*
*/
struct sci_sas_address {
u32 high;
u32 low;
};
#endif
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