From: John Hubbard Date: Fri, 6 Aug 2021 06:53:30 +0000 (-0700) Subject: net: mvvp2: fix short frame size on s390 X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=704e624f7b3e8a4fc1ce43fb564746d1d07b20c0;p=linux.git net: mvvp2: fix short frame size on s390 On s390, the following build warning occurs: drivers/net/ethernet/marvell/mvpp2/mvpp2.h:844:2: warning: overflow in conversion from 'long unsigned int' to 'int' changes value from '18446744073709551584' to '-32' [-Woverflow] 844 | ((total_size) - MVPP2_SKB_HEADROOM - MVPP2_SKB_SHINFO_SIZE) This happens because MVPP2_SKB_SHINFO_SIZE, which is 320 bytes (which is already 64-byte aligned) on some architectures, actually gets ALIGN'd up to 512 bytes in the s390 case. So then, when this is invoked: MVPP2_RX_MAX_PKT_SIZE(MVPP2_BM_SHORT_FRAME_SIZE) ...that turns into: 704 - 224 - 512 == -32 ...which is not a good frame size to end up with! The warning above is a bit lucky: it notices a signed/unsigned bad behavior here, which leads to the real problem of a frame that is too short for its contents. Increase MVPP2_BM_SHORT_FRAME_SIZE by 32 (from 704 to 736), which is just exactly big enough. (The other values can't readily be changed without causing a lot of other problems.) Fixes: 07dd0a7aae7f ("mvpp2: add basic XDP support") Cc: Sven Auhagen Cc: Matteo Croce Cc: David S. Miller Signed-off-by: John Hubbard Signed-off-by: David S. Miller --- diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2.h b/drivers/net/ethernet/marvell/mvpp2/mvpp2.h index b9fbc9f000f2f..cf8acabb90ac1 100644 --- a/drivers/net/ethernet/marvell/mvpp2/mvpp2.h +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2.h @@ -938,7 +938,7 @@ enum mvpp22_ptp_packet_format { #define MVPP2_BM_COOKIE_POOL_OFFS 8 #define MVPP2_BM_COOKIE_CPU_OFFS 24 -#define MVPP2_BM_SHORT_FRAME_SIZE 704 /* frame size 128 */ +#define MVPP2_BM_SHORT_FRAME_SIZE 736 /* frame size 128 */ #define MVPP2_BM_LONG_FRAME_SIZE 2240 /* frame size 1664 */ #define MVPP2_BM_JUMBO_FRAME_SIZE 10432 /* frame size 9856 */ /* BM short pool packet size