Commit a55a603d authored by Vasanthy Kolluri's avatar Vasanthy Kolluri Committed by David S. Miller
Browse files

enic: Bug Fix: Fix hardware descriptor reads 



The last bit written to a completion descriptor by hardware is the color
bit. Driver must read all other descriptor fields only after reading the
color bit to avoid reading stale descriptor fields.  There is a rmb() after
reading the color bit to avoid any compiler/cpu reordering of the reads.
The color bit is the generation bit that toggles each pass through the
completion descriptor ring.

Signed-off-by: default avatarScott Feldman <scofeldm@cisco.com>
Signed-off-by: default avatarVasanthy Kolluri <vkolluri@cisco.com>
Signed-off-by: default avatarRoopa Prabhu <roprabhu@cisco.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ba7e94a4

drivers/net/enic/cq_enet_desc.h

+8 −4
Original line number Diff line number Diff line
@@ -101,14 +101,18 @@ static inline void cq_enet_rq_desc_dec(struct cq_enet_rq_desc *desc, 
	u8 *tcp_udp_csum_ok, u8 *udp, u8 *tcp, u8 *ipv4_csum_ok,

	u8 *ipv6, u8 *ipv4, u8 *ipv4_fragment, u8 *fcs_ok)

{

	u16 completed_index_flags = le16_to_cpu(desc->completed_index_flags);

	u16 q_number_rss_type_flags =

		le16_to_cpu(desc->q_number_rss_type_flags);

	u16 bytes_written_flags = le16_to_cpu(desc->bytes_written_flags);

	u16 completed_index_flags;

	u16 q_number_rss_type_flags;

	u16 bytes_written_flags;



	cq_desc_dec((struct cq_desc *)desc, type,

		color, q_number, completed_index);



	completed_index_flags = le16_to_cpu(desc->completed_index_flags);

	q_number_rss_type_flags =

		le16_to_cpu(desc->q_number_rss_type_flags);

	bytes_written_flags = le16_to_cpu(desc->bytes_written_flags);



	*ingress_port = (completed_index_flags &

		CQ_ENET_RQ_DESC_FLAGS_INGRESS_PORT) ? 1 : 0;

	*fcoe = (completed_index_flags & CQ_ENET_RQ_DESC_FLAGS_FCOE) ?

drivers/net/enic/enic.h

+1 −1
Original line number Diff line number Diff line
@@ -34,7 +34,7 @@ 


#define DRV_NAME		"enic"

#define DRV_DESCRIPTION		"Cisco 10G Ethernet Driver"

#define DRV_VERSION		"1.1.0.241a"

#define DRV_VERSION		"1.3.1.1"

#define DRV_COPYRIGHT		"Copyright 2008-2009 Cisco Systems, Inc"

#define PFX			DRV_NAME ": "

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