bnxt_en: reserve space inside receive page for skb_shared_info

BugLink: https://bugs.launchpad.net/bugs/1971497
[ Upstream commit facc173cf700e55b2ad249ecbd3a7537f7315691 ]

Insufficient space was being reserved in the page used for packet
reception, so the interface MTU could be set too large to still have
room for the contents of the packet when doing XDP redirect.  This
resulted in the following message when redirecting a packet between
3520 and 3822 bytes with an MTU of 3822:

[311815.561880] XDP_WARN: xdp_update_frame_from_buff(line:200): Driver BUG: missing reserved tailroom

Fixes: f18c2b77b2e4 ("bnxt_en: optimized XDP_REDIRECT support")
Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: Andy Gospodarek <gospo@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.h b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
index 8ba369c0100b473253c86ef5b2f83454c415c90d..9e8a0c772ca93e32326116200b45db549d66777f 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
@@ -559,7 +559,8 @@ struct nqe_cn {
 #define BNXT_MAX_MTU           9500
 #define BNXT_MAX_PAGE_MODE_MTU \
        ((unsigned int)PAGE_SIZE - VLAN_ETH_HLEN - NET_IP_ALIGN -       \
-        XDP_PACKET_HEADROOM)
+        XDP_PACKET_HEADROOM - \
+        SKB_DATA_ALIGN((unsigned int)sizeof(struct skb_shared_info)))
 
 #define BNXT_MIN_PKT_SIZE      52