From: David Howells <dhowells@redhat.com>
To: linux-afs@lists.infradead.org
Cc: dhowells@redhat.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 09/13] rxrpc: Use ACCESS_ONCE() when accessing circular buffer pointers
Date: Fri, 04 Mar 2016 16:38:08 +0000 [thread overview]
Message-ID: <20160304163808.31057.35519.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <20160304163705.31057.60831.stgit@warthog.procyon.org.uk>
Use ACCESS_ONCE() when accessing the other-end pointer into a circular
buffer as it's possible the other-end pointer might change whilst we're
doing this, and if we access it twice, we might get some weird things
happening.
Signed-off-by: David Howells <dhowells@redhat.com>
---
net/rxrpc/ar-output.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/net/rxrpc/ar-output.c b/net/rxrpc/ar-output.c
index 353f5c9141ea..14c8df6b7f41 100644
--- a/net/rxrpc/ar-output.c
+++ b/net/rxrpc/ar-output.c
@@ -401,7 +401,8 @@ static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
int ret;
_enter(",{%d},%ld",
- CIRC_SPACE(call->acks_head, call->acks_tail, call->acks_winsz),
+ CIRC_SPACE(call->acks_head, ACCESS_ONCE(call->acks_tail),
+ call->acks_winsz),
*timeo);
add_wait_queue(&call->tx_waitq, &myself);
@@ -409,7 +410,7 @@ static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
for (;;) {
set_current_state(TASK_INTERRUPTIBLE);
ret = 0;
- if (CIRC_SPACE(call->acks_head, call->acks_tail,
+ if (CIRC_SPACE(call->acks_head, ACCESS_ONCE(call->acks_tail),
call->acks_winsz) > 0)
break;
if (signal_pending(current)) {
@@ -570,7 +571,8 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
_debug("alloc");
- if (CIRC_SPACE(call->acks_head, call->acks_tail,
+ if (CIRC_SPACE(call->acks_head,
+ ACCESS_ONCE(call->acks_tail),
call->acks_winsz) <= 0) {
ret = -EAGAIN;
if (msg->msg_flags & MSG_DONTWAIT)
@@ -686,7 +688,8 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
sp->hdr.flags = conn->out_clientflag;
if (msg_data_left(msg) == 0 && !more)
sp->hdr.flags |= RXRPC_LAST_PACKET;
- else if (CIRC_SPACE(call->acks_head, call->acks_tail,
+ else if (CIRC_SPACE(call->acks_head,
+ ACCESS_ONCE(call->acks_tail),
call->acks_winsz) > 1)
sp->hdr.flags |= RXRPC_MORE_PACKETS;
if (more && seq & 1)
next prev parent reply other threads:[~2016-03-04 16:38 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-04 16:37 [PATCH 00/13] RxRPC: Rewrite part 1 David Howells
2016-03-04 16:37 ` [PATCH 01/13] rxrpc: Fix a case where a call event bit is being used as a flag bit David Howells
2016-03-04 16:37 ` [PATCH 02/13] rxrpc: Convert call flag and event numbers into enums David Howells
2016-03-04 16:37 ` [PATCH 03/13] rxrpc: Rename call events to begin RXRPC_CALL_EV_ David Howells
2016-03-04 16:37 ` [PATCH 04/13] rxrpc: Keep the skb private record of the Rx header in host byte order David Howells
2016-03-04 16:37 ` [PATCH 05/13] rxrpc: The protocol family should be set to PF_RXRPC not PF_UNIX David Howells
2016-03-04 16:37 ` [PATCH 06/13] rxrpc: Fix defined range for /proc/sys/net/rxrpc/rx_mtu David Howells
2016-03-04 16:37 ` [PATCH 07/13] rxrpc: Be more selective about the types of received packets we accept David Howells
2016-03-04 16:38 ` [PATCH 08/13] rxrpc: Adjust some whitespace and comments David Howells
2016-03-04 16:38 ` David Howells [this message]
2016-03-04 16:38 ` [PATCH 10/13] rxrpc: rxkad: The version number in the response should be net byte order David Howells
2016-03-04 16:38 ` [PATCH 11/13] rxrpc: rxkad: Casts are needed when comparing be32 values David Howells
2016-03-04 16:38 ` [PATCH 12/13] rxrpc: Clear the unused part of a sockaddr_rxrpc for memcmp() use David Howells
2016-03-04 16:38 ` [PATCH 13/13] rxrpc: Don't try to map ICMP to error as the lower layer already did that David Howells
2016-03-04 22:20 ` [PATCH 00/13] RxRPC: Rewrite part 1 David Miller
2016-03-04 22:33 ` David Howells
2016-03-04 23:27 ` David Miller
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