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![Gustavo A. R. Silva](/assets/img/avatar_default.png)
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>
96 lines
2.2 KiB
C
96 lines
2.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* iSCSI Transport BSG Interface
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*
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* Copyright (C) 2009 James Smart, Emulex Corporation
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*/
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#ifndef SCSI_BSG_ISCSI_H
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#define SCSI_BSG_ISCSI_H
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/*
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* This file intended to be included by both kernel and user space
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*/
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#include <scsi/scsi.h>
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/*
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* iSCSI Transport SGIO v4 BSG Message Support
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*/
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/* Default BSG request timeout (in seconds) */
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#define ISCSI_DEFAULT_BSG_TIMEOUT (10 * HZ)
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/*
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* Request Message Codes supported by the iSCSI Transport
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*/
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/* define the class masks for the message codes */
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#define ISCSI_BSG_CLS_MASK 0xF0000000 /* find object class */
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#define ISCSI_BSG_HST_MASK 0x80000000 /* iscsi host class */
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/* iscsi host Message Codes */
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#define ISCSI_BSG_HST_VENDOR (ISCSI_BSG_HST_MASK | 0x000000FF)
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/*
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* iSCSI Host Messages
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*/
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/* ISCSI_BSG_HST_VENDOR : */
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/* Request:
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* Note: When specifying vendor_id, be sure to read the Vendor Type and ID
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* formatting requirements specified in scsi_netlink.h
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*/
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struct iscsi_bsg_host_vendor {
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/*
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* Identifies the vendor that the message is formatted for. This
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* should be the recipient of the message.
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*/
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uint64_t vendor_id;
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/* start of vendor command area */
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uint32_t vendor_cmd[];
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};
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/* Response:
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*/
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struct iscsi_bsg_host_vendor_reply {
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/* start of vendor response area */
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uint32_t vendor_rsp[0];
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};
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/* request (CDB) structure of the sg_io_v4 */
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struct iscsi_bsg_request {
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uint32_t msgcode;
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union {
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struct iscsi_bsg_host_vendor h_vendor;
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} rqst_data;
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} __attribute__((packed));
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/* response (request sense data) structure of the sg_io_v4 */
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struct iscsi_bsg_reply {
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/*
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* The completion result. Result exists in two forms:
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* if negative, it is an -Exxx system errno value. There will
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* be no further reply information supplied.
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* else, it's the 4-byte scsi error result, with driver, host,
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* msg and status fields. The per-msgcode reply structure
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* will contain valid data.
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*/
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uint32_t result;
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/* If there was reply_payload, how much was recevied ? */
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uint32_t reply_payload_rcv_len;
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union {
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struct iscsi_bsg_host_vendor_reply vendor_reply;
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} reply_data;
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};
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#endif /* SCSI_BSG_ISCSI_H */
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