scsi: Replace zero-length array with flexible-array member (5febf6d6) · Commits · 戴 / test

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 ("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>

drivers/scsi/fnic/vnic_devcmd.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -442,7 +442,7 @@ struct vnic_devcmd_notify {
		struct vnic_devcmd_provinfo {
		u8 oui[3];
		u8 type;
		u8 data[0];
		u8 data[];
		};

		/*

drivers/scsi/ipr.h

+3 −3

Original line number	Diff line number	Diff line
		@@ -451,12 +451,12 @@ struct ipr_config_table_hdr64 {

		struct ipr_config_table {
		struct ipr_config_table_hdr hdr;
		struct ipr_config_table_entry dev[0];
		struct ipr_config_table_entry dev[];
		}__attribute__((packed, aligned (4)));

		struct ipr_config_table64 {
		struct ipr_config_table_hdr64 hdr64;
		struct ipr_config_table_entry64 dev[0];
		struct ipr_config_table_entry64 dev[];
		}__attribute__((packed, aligned (8)));

		struct ipr_config_table_entry_wrapper {
		@@ -792,7 +792,7 @@ struct ipr_mode_page28 {
		struct ipr_mode_page_hdr hdr;
		u8 num_entries;
		u8 entry_length;
		struct ipr_dev_bus_entry bus[0];
		struct ipr_dev_bus_entry bus[];
		}__attribute__((packed));

		struct ipr_mode_page24 {

drivers/scsi/isci/sas.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -201,7 +201,7 @@ struct smp_req {
		u8 func; /* byte 1 */
		u8 alloc_resp_len; /* byte 2 */
		u8 req_len; /* byte 3 */
		u8 req_data[0];
		u8 req_data[];
		} __packed;

		/*

drivers/scsi/mpt3sas/mpt3sas_scsih.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -207,7 +207,7 @@ struct fw_event_work {
		u8 ignore;
		u16 event;
		struct kref refcount;
		char event_data[0] __aligned(4);
		char event_data[] __aligned(4);
		};

		static void fw_event_work_free(struct kref *r)

drivers/scsi/mvsas/mv_sas.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -394,7 +394,7 @@ struct mvs_info {
		dma_addr_t bulk_buffer_dma1;
		#define TRASH_BUCKET_SIZE 0x20000
		void *dma_pool;
		struct mvs_slot_info slot_info[0];
		struct mvs_slot_info slot_info[];
		};

		struct mvs_prv_info{

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