Commit e2243720 authored Jun 05, 2020 by Alexander Lobakin Committed by David S. Miller Jun 05, 2020

net: ethernet: mvneta: fix MVNETA_SKB_HEADROOM alignment



Commit ca23cb0b ("mvneta: MVNETA_SKB_HEADROOM set last 3 bits to zero")
added headroom alignment check against 8.
Hovewer (if we imagine that NET_SKB_PAD or XDP_PACKET_HEADROOM is not
aligned to cacheline size), it actually aligns headroom down, while
skb/xdp_buff headroom should be *at least* equal to one of the values
(depending on XDP prog presence).
So, fix the check to align the value up. This satisfies both
hardware/driver and network stack requirements.

Fixes: ca23cb0b ("mvneta: MVNETA_SKB_HEADROOM set last 3 bits to zero")
Signed-off-by: Alexander Lobakin <bloodyreaper@yandex.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 178f67b1

drivers/net/ethernet/marvell/mvneta.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -325,7 +325,7 @@
		cache_line_size())

		/* Driver assumes that the last 3 bits are 0 */
		#define MVNETA_SKB_HEADROOM (max(XDP_PACKET_HEADROOM, NET_SKB_PAD) & ~0x7)
		#define MVNETA_SKB_HEADROOM ALIGN(max(NET_SKB_PAD, XDP_PACKET_HEADROOM), 8)
		#define MVNETA_SKB_PAD (SKB_DATA_ALIGN(sizeof(struct skb_shared_info) + \
		MVNETA_SKB_HEADROOM))
		#define MVNETA_SKB_SIZE(len) (SKB_DATA_ALIGN(len) + MVNETA_SKB_PAD)

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