2017-09-05 15:42:38

by Haakon Bugge

Subject: [PATCH net] rds: Fix non-atomic operation on shared flag variable

The bits in m_flags in struct rds_message are used for a plurality of
reasons, and from different contexts. To avoid any missing updates to
m_flags, use the atomic set_bit() instead of the non-atomic equivalent.

Signed-off-by: Håkon Bugge <[email protected]>
Reviewed-by: Knut Omang <[email protected]>
Reviewed-by: Wei Lin Guay <[email protected]>
---
net/rds/send.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/rds/send.c b/net/rds/send.c
index 41b9f0f..058a407 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c
@@ -273,7 +273,7 @@ int rds_send_xmit(struct rds_conn_path *cp)
len = ntohl(rm->m_inc.i_hdr.h_len);
if (cp->cp_unacked_packets == 0 ||
cp->cp_unacked_bytes < len) {
- __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
+ set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);

cp->cp_unacked_packets =
rds_sysctl_max_unacked_packets;
@@ -829,7 +829,7 @@ static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
* throughput hits a certain threshold.
*/
if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
- __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
+ set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);

list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
--
2.9.3

2017-09-05 16:32:34

by Santosh Shilimkar

Subject: Re: [PATCH net] rds: Fix non-atomic operation on shared flag variable

On 9/5/2017 8:42 AM, Håkon Bugge wrote:
> The bits in m_flags in struct rds_message are used for a plurality of
> reasons, and from different contexts. To avoid any missing updates to
> m_flags, use the atomic set_bit() instead of the non-atomic equivalent.
>
> Signed-off-by: Håkon Bugge <[email protected]>
> Reviewed-by: Knut Omang <[email protected]>
> Reviewed-by: Wei Lin Guay <[email protected]>
> ---
> net/rds/send.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/net/rds/send.c b/net/rds/send.c
> index 41b9f0f..058a407 100644
> --- a/net/rds/send.c
> +++ b/net/rds/send.c
> @@ -273,7 +273,7 @@ int rds_send_xmit(struct rds_conn_path *cp)
> len = ntohl(rm->m_inc.i_hdr.h_len);
> if (cp->cp_unacked_packets == 0 ||
> cp->cp_unacked_bytes < len) {
> - __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
> + set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
>
> cp->cp_unacked_packets =
> rds_sysctl_max_unacked_packets;
> @@ -829,7 +829,7 @@ static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
> * throughput hits a certain threshold.
> */
> if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
> - __set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
> + set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
>
> list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
> set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
>
Indeed, these couple of instances remained for the m_flags.
Patch looks good. Thanks !!

Acked-by: Santosh Shilimkar <[email protected]>

2017-09-05 21:50:04

by David Miller

Subject: Re: [PATCH net] rds: Fix non-atomic operation on shared flag variable

From: H?kon Bugge <[email protected]>
Date: Tue, 5 Sep 2017 17:42:01 +0200

> The bits in m_flags in struct rds_message are used for a plurality of
> reasons, and from different contexts. To avoid any missing updates to
> m_flags, use the atomic set_bit() instead of the non-atomic equivalent.
>
> Signed-off-by: H?kon Bugge <[email protected]>
> Reviewed-by: Knut Omang <[email protected]>
> Reviewed-by: Wei Lin Guay <[email protected]>

Applied.