[PATCH] tg3: Use slab_build_skb() when needed

[Kees Cook]

The tg3 driver will use kmalloc() under some conditions. Check the
frag_size and use slab_build_skb() when frag_size is 0. Silences
the warning introduced by commit ce098da1497c ("skbuff: Introduce
slab_build_skb()"):

	Use slab_build_skb() instead
	...
	tg3_poll_work+0x638/0xf90 [tg3]

Reported-by: Fiona Ebner <f.ebner@xxxxxxxxxxx>
Closes: https://lore.kernel.org/all/1bd4cb9c-4eb8-3bdb-3e05-8689817242d1@xxxxxxxxxxx
Cc: Siva Reddy Kallam <siva.kallam@xxxxxxxxxxxx>
Cc: Prashant Sreedharan <prashant@xxxxxxxxxxxx>
Cc: Michael Chan <mchan@xxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
Cc: Bagas Sanjaya <bagasdotme@xxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
 drivers/net/ethernet/broadcom/tg3.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index 5ef073a79ce9..cb2810f175cc 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -6881,7 +6881,10 @@ static int tg3_rx(struct tg3_napi *tnapi, int budget)
 
 			ri->data = NULL;
 
-			skb = build_skb(data, frag_size);
+			if (frag_size)
+				skb = build_skb(data, frag_size);
+			else
+				skb = slab_build_skb(data);
 			if (!skb) {
 				tg3_frag_free(frag_size != 0, data);
 				goto drop_it_no_recycle;
-- 
2.34.1