octeontx2-af: use unsigned int as iterator for unsigned values

The local variable i is used to iterate over unsigned
values. The lower bound of the loop is set to 0. While
the upper bound is cgx->lmac_count, where they lmac_count is
an u8. So the theoretical upper bound is 255.

As is, GCC can't see this range of values and warns that
a formatted string, which includes the %d representation of i,
may overflow the buffer provided.

GCC 15.1.0 says:

  .../cgx.c: In function 'cgx_lmac_init':
  .../cgx.c:1737:49: warning: '%d' directive writing between 1 and 11 bytes into a region of size between 4 and 6 [-Wformat-overflow=]
   1737 |                 sprintf(lmac->name, "cgx_fwi_%d_%d", cgx->cgx_id, i);
        |                                                 ^~
  .../cgx.c:1737:37: note: directive argument in the range [-2147483641, 254]
   1737 |                 sprintf(lmac->name, "cgx_fwi_%d_%d", cgx->cgx_id, i);
        |                                     ^~~~~~~~~~~~~~~
  .../cgx.c:1737:17: note: 'sprintf' output between 12 and 24 bytes into a destination of size 16
   1737 |                 sprintf(lmac->name, "cgx_fwi_%d_%d", cgx->cgx_id, i);
        |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Empirically, changing the type of i from (signed) int to unsigned int
addresses this problem. I assume by allowing GCC to see the range of
values described above.

Also update the format specifiers for the integer values in the string
in question from %d to %u. This seems appropriate as they are now both
unsigned.

No functional change intended.
Compile tested only.

Signed-off-by: Simon Horman <horms@kernel.org>
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Link: https://patch.msgid.link/20250724-octeontx2-af-unsigned-v1-1-c745c106e06f@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/marvell/octeontx2/af/cgx.c b/drivers/net/ethernet/marvell/octeontx2/af/cgx.c
index ab5838865c3f875c074248a0a9c7595115147d83..4ff19a04b23ee6848105a67a29d44cd3da35f2fe 100644 (file)
--- a/drivers/net/ethernet/marvell/octeontx2/af/cgx.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/cgx.c
@@ -1706,9 +1706,9 @@ static int cgx_lmac_init(struct cgx *cgx)
 {
        u8 max_dmac_filters;
        struct lmac *lmac;
+       int err, filter;
+       unsigned int i;
        u64 lmac_list;
-       int i, err;
-       int filter;
 
        /* lmac_list specifies which lmacs are enabled
         * when bit n is set to 1, LMAC[n] is enabled
@@ -1734,7 +1734,7 @@ static int cgx_lmac_init(struct cgx *cgx)
                        err = -ENOMEM;
                        goto err_lmac_free;
                }
-               sprintf(lmac->name, "cgx_fwi_%d_%d", cgx->cgx_id, i);
+               sprintf(lmac->name, "cgx_fwi_%u_%u", cgx->cgx_id, i);
                if (cgx->mac_ops->non_contiguous_serdes_lane) {
                        lmac->lmac_id = __ffs64(lmac_list);
                        lmac_list   &= ~BIT_ULL(lmac->lmac_id);