Commit 65dc2f1a authored by Gustavo A. R. Silva's avatar Gustavo A. R. Silva Committed by David S. Miller
Browse files

chelsio: 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 76497732 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: default avatarGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 59bc954c

drivers/net/ethernet/chelsio/cxgb3/cxgb3_ioctl.h

+1 −1
Original line number Diff line number Diff line
@@ -79,7 +79,7 @@ struct ch_mem_range { 
	uint32_t addr;

	uint32_t len;

	uint32_t version;

	uint8_t buf[0];

	uint8_t buf[];

};



struct ch_qset_params {

drivers/net/ethernet/chelsio/cxgb3/t3_cpl.h

+1 −1
Original line number Diff line number Diff line
@@ -1448,7 +1448,7 @@ struct cpl_rdma_terminate { 
#endif

	__be32 msn;

	__be32 mo;

	__u8 data[0];

	__u8 data[];

};



/* cpl_rdma_terminate.tid_len fields */

drivers/net/ethernet/chelsio/cxgb4/clip_tbl.h

+1 −1
Original line number Diff line number Diff line
@@ -29,7 +29,7 @@ struct clip_tbl { 
	atomic_t nfree;

	struct list_head ce_free_head;

	void *cl_list;

	struct list_head hash_list[0];

	struct list_head hash_list[];

};



enum {

drivers/net/ethernet/chelsio/cxgb4/cudbg_entity.h

+4 −4
Original line number Diff line number Diff line
@@ -82,7 +82,7 @@ struct cudbg_ulprx_la { 
struct cudbg_tp_la {

	u32 size;

	u32 mode;

	u8 data[0];

	u8 data[];

};



static const char * const cudbg_region[] = {
@@ -134,7 +134,7 @@ struct cudbg_meminfo { 


struct cudbg_cim_pif_la {

	int size;

	u8 data[0];

	u8 data[];

};



struct cudbg_clk_info {
@@ -339,13 +339,13 @@ struct cudbg_qdesc_entry { 
	u32 qid;

	u32 desc_size;

	u32 num_desc;

	u8 data[0]; /* Must be last */

	u8 data[]; /* Must be last */

};



struct cudbg_qdesc_info {

	u32 qdesc_entry_size;

	u32 num_queues;

	u8 data[0]; /* Must be last */

	u8 data[]; /* Must be last */

};



#define IREG_NUM_ELEM 4

drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c

+1 −1
Original line number Diff line number Diff line
@@ -984,7 +984,7 @@ static const char * const devlog_facility_strings[] = { 
struct devlog_info {

	unsigned int nentries;		/* number of entries in log[] */

	unsigned int first;		/* first [temporal] entry in log[] */

	struct fw_devlog_e log[0];	/* Firmware Device Log */

	struct fw_devlog_e log[];	/* Firmware Device Log */

};



/* Dump a Firmaware Device Log entry.