Return-Path: linux-nfs-owner@vger.kernel.org Received: from smtp02.citrix.com ([66.165.176.63]:60785 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757331Ab2ECO7Y (ORCPT ); Thu, 3 May 2012 10:59:24 -0400 From: Ian Campbell To: netdev@vger.kernel.org CC: David Miller , Eric Dumazet , "Michael S. Tsirkin" , Ian Campbell , Neil Brown , "J. Bruce Fields" , linux-nfs@vger.kernel.org Subject: [PATCH 9/9] sunrpc: use SKB fragment destructors to delay completion until page is released by network stack. Date: Thu, 3 May 2012 15:56:11 +0100 Message-ID: <1336056971-7839-9-git-send-email-ian.campbell@citrix.com> In-Reply-To: <1336056915.20716.96.camel@zakaz.uk.xensource.com> References: <1336056915.20716.96.camel@zakaz.uk.xensource.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-nfs-owner@vger.kernel.org List-ID: This prevents an issue where an ACK is delayed, a retransmit is queued (either at the RPC or TCP level) and the ACK arrives before the retransmission hits the wire. If this happens to an NFS WRITE RPC then the write() system call completes and the userspace process can continue, potentially modifying data referenced by the retransmission before the retransmission occurs. Signed-off-by: Ian Campbell Acked-by: Trond Myklebust Cc: "David S. Miller" Cc: Neil Brown Cc: "J. Bruce Fields" Cc: linux-nfs@vger.kernel.org Cc: netdev@vger.kernel.org --- include/linux/sunrpc/xdr.h | 2 ++ include/linux/sunrpc/xprt.h | 5 ++++- net/sunrpc/clnt.c | 27 ++++++++++++++++++++++----- net/sunrpc/svcsock.c | 3 ++- net/sunrpc/xprt.c | 12 ++++++++++++ net/sunrpc/xprtsock.c | 3 ++- 6 files changed, 44 insertions(+), 8 deletions(-) diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h index af70af3..ff1b121 100644 --- a/include/linux/sunrpc/xdr.h +++ b/include/linux/sunrpc/xdr.h @@ -16,6 +16,7 @@ #include #include #include +#include /* * Buffer adjustment @@ -57,6 +58,7 @@ struct xdr_buf { tail[1]; /* Appended after page data */ struct page ** pages; /* Array of contiguous pages */ + struct skb_frag_destructor *destructor; unsigned int page_base, /* Start of page data */ page_len, /* Length of page data */ flags; /* Flags for data disposition */ diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index 77d278d..e8d3f18 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -92,7 +92,10 @@ struct rpc_rqst { /* A cookie used to track the state of the transport connection */ - + struct skb_frag_destructor destructor; /* SKB paged fragment + * destructor for + * transmitted pages*/ + /* * Partial send handling */ diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index 6797246..351bf3d 100644 --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -61,6 +61,7 @@ static void call_reserve(struct rpc_task *task); static void call_reserveresult(struct rpc_task *task); static void call_allocate(struct rpc_task *task); static void call_decode(struct rpc_task *task); +static void call_complete(struct rpc_task *task); static void call_bind(struct rpc_task *task); static void call_bind_status(struct rpc_task *task); static void call_transmit(struct rpc_task *task); @@ -1416,6 +1417,8 @@ rpc_xdr_encode(struct rpc_task *task) (char *)req->rq_buffer + req->rq_callsize, req->rq_rcvsize); + req->rq_snd_buf.destructor = &req->destructor; + p = rpc_encode_header(task); if (p == NULL) { printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n"); @@ -1581,6 +1584,7 @@ call_connect_status(struct rpc_task *task) static void call_transmit(struct rpc_task *task) { + struct rpc_rqst *req = task->tk_rqstp; dprint_status(task); task->tk_action = call_status; @@ -1614,8 +1618,8 @@ call_transmit(struct rpc_task *task) call_transmit_status(task); if (rpc_reply_expected(task)) return; - task->tk_action = rpc_exit_task; - rpc_wake_up_queued_task(&task->tk_xprt->pending, task); + task->tk_action = call_complete; + skb_frag_destructor_unref(&req->destructor); } /* @@ -1688,7 +1692,8 @@ call_bc_transmit(struct rpc_task *task) return; } - task->tk_action = rpc_exit_task; + task->tk_action = call_complete; + skb_frag_destructor_unref(&req->destructor); if (task->tk_status < 0) { printk(KERN_NOTICE "RPC: Could not send backchannel reply " "error: %d\n", task->tk_status); @@ -1728,7 +1733,6 @@ call_bc_transmit(struct rpc_task *task) "error: %d\n", task->tk_status); break; } - rpc_wake_up_queued_task(&req->rq_xprt->pending, task); } #endif /* CONFIG_SUNRPC_BACKCHANNEL */ @@ -1906,12 +1910,14 @@ call_decode(struct rpc_task *task) return; } - task->tk_action = rpc_exit_task; + task->tk_action = call_complete; if (decode) { task->tk_status = rpcauth_unwrap_resp(task, decode, req, p, task->tk_msg.rpc_resp); } + rpc_sleep_on(&req->rq_xprt->pending, task, NULL); + skb_frag_destructor_unref(&req->destructor); dprintk("RPC: %5u call_decode result %d\n", task->tk_pid, task->tk_status); return; @@ -1926,6 +1932,17 @@ out_retry: } } +/* + * 8. Wait for pages to be released by the network stack. + */ +static void +call_complete(struct rpc_task *task) +{ + dprintk("RPC: %5u call_complete result %d\n", + task->tk_pid, task->tk_status); + task->tk_action = rpc_exit_task; +} + static __be32 * rpc_encode_header(struct rpc_task *task) { diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index f6d8c73..1145929 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -198,7 +198,8 @@ int svc_send_common(struct socket *sock, struct xdr_buf *xdr, while (pglen > 0) { if (slen == size) flags = 0; - result = kernel_sendpage(sock, *ppage, NULL, base, size, flags); + result = kernel_sendpage(sock, *ppage, xdr->destructor, + base, size, flags); if (result > 0) len += result; if (result != size) diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 6fe2dce..f8418a0 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -1108,6 +1108,16 @@ static inline void xprt_init_xid(struct rpc_xprt *xprt) xprt->xid = net_random(); } +static int xprt_complete_skb_pages(struct skb_frag_destructor *destroy) +{ + struct rpc_rqst *req = + container_of(destroy, struct rpc_rqst, destructor); + + dprintk("RPC: %5u completing skb pages\n", req->rq_task->tk_pid); + rpc_wake_up_queued_task(&req->rq_xprt->pending, req->rq_task); + return 0; +} + static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt) { struct rpc_rqst *req = task->tk_rqstp; @@ -1120,6 +1130,8 @@ static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt) req->rq_xid = xprt_alloc_xid(xprt); req->rq_release_snd_buf = NULL; xprt_reset_majortimeo(req); + atomic_set(&req->destructor.ref, 1); + req->destructor.destroy = &xprt_complete_skb_pages; dprintk("RPC: %5u reserved req %p xid %08x\n", task->tk_pid, req, ntohl(req->rq_xid)); } diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index f1995dc..44e07f3 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -408,7 +408,8 @@ static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned i remainder -= len; if (remainder != 0 || more) flags |= MSG_MORE; - err = sock->ops->sendpage(sock, *ppage, NULL, base, len, flags); + err = sock->ops->sendpage(sock, *ppage, xdr->destructor, + base, len, flags); if (remainder == 0 || err != len) break; sent += err; -- 1.7.2.5