Commit f8d0efb1 authored Jun 11, 2018 by Jakub Kicinski Committed by David S. Miller Jun 12, 2018

nfp: don't pad strings in nfp_cpp_resource_find() to avoid gcc 8 warning



Once upon a time nfp_cpp_resource_find() took a name parameter,
which could be any user-chosen string.  Resources are identified
by a CRC32 hash of a 8 byte string, so we had to pad user input
with zeros to make sure CRC32 gave the correct result.

Since then nfp_cpp_resource_find() was made to operate on allocated
resources only (struct nfp_resource).  We kzalloc those so there is
no need to pad the strings and use memcmp.

This avoids a GCC 8 stringop-truncation warning:

In function ‘nfp_cpp_resource_find’,
    inlined from ‘nfp_resource_try_acquire’ at .../nfpcore/nfp_resource.c:153:8,
    inlined from ‘nfp_resource_acquire’ at .../nfpcore/nfp_resource.c:206:9:
    .../nfpcore/nfp_resource.c:108:2: warning:  strncpy’ output may be truncated copying 8 bytes from a string of length 8 [-Wstringop-truncation]
      strncpy(name_pad, res->name, sizeof(name_pad));
      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent cdb8744d

drivers/net/ethernet/netronome/nfp/nfpcore/nfp_resource.c

+2 −5

Original line number	Diff line number	Diff line
		@@ -98,21 +98,18 @@ struct nfp_resource {

		static int nfp_cpp_resource_find(struct nfp_cpp cpp, struct nfp_resource res)
		{
		char name_pad[NFP_RESOURCE_ENTRY_NAME_SZ] = {};
		struct nfp_resource_entry entry;
		u32 cpp_id, key;
		int ret, i;

		cpp_id = NFP_CPP_ID(NFP_RESOURCE_TBL_TARGET, 3, 0); /* Atomic read */

		strncpy(name_pad, res->name, sizeof(name_pad));

		/* Search for a matching entry */
		if (!memcmp(name_pad, NFP_RESOURCE_TBL_NAME "\0\0\0\0\0\0\0\0", 8)) {
		if (!strcmp(res->name, NFP_RESOURCE_TBL_NAME)) {
		nfp_err(cpp, "Grabbing device lock not supported\n");
		return -EOPNOTSUPP;
		}
		key = crc32_posix(name_pad, sizeof(name_pad));
		key = crc32_posix(res->name, NFP_RESOURCE_ENTRY_NAME_SZ);

		for (i = 0; i < NFP_RESOURCE_TBL_ENTRIES; i++) {
		u64 addr = NFP_RESOURCE_TBL_BASE +