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net: mvvp2: fix short frame size on s390

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[ Upstream commit 704e624f7b3e8a4fc1ce43fb564746d1d07b20c0 ]

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: 07dd0a7aae ("mvpp2: add basic XDP support")
Cc: Sven Auhagen <sven.auhagen@voleatech.de>
Cc: Matteo Croce <mcroce@microsoft.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
John Hubbard 2021-08-05 23:53:30 -07:00 committed by AuxXxilium
parent 390acd6e6a
commit b25cf69b2b
1 changed files with 1 additions and 1 deletions
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2
drivers/net/ethernet/marvell/mvpp2/mvpp2.h
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@ -854,7 +854,7 @@ 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