Re: [PATCH 3.12 34/72] Fix regression in NFSRDMA server

[Tom Tucker <tom@opengridcomputing.com>]

Seems like part of a patch was dropped or there was a merge problem. The 
code in my tree has all these changes. Very strange.

Tom

On 11/23/15 7:08 AM, Jiri Slaby wrote:
> From: Tom Tucker <tom@ogc.us>
>
> 3.12-stable review patch.  If anyone has any objections, please let me know.
>
> ===============
>
> commit 7e4359e2611f95a97037e2b6905eab52f28afbeb upstream.
>
> The server regression was caused by the addition of rq_next_page
> (afc59400d6c65bad66d4ad0b2daf879cbff8e23e). There were a few places that
> were missed with the update of the rq_respages array.
>
> Signed-off-by: Tom Tucker <tom@ogc.us>
> Tested-by: Steve Wise <swise@ogc.us>
> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
> ---
>   net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 12 ++++--------
>   net/sunrpc/xprtrdma/svc_rdma_sendto.c   |  1 +
>   2 files changed, 5 insertions(+), 8 deletions(-)
>
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> index 0ce75524ed21..8d904e4eef15 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
> @@ -90,6 +90,7 @@ static void rdma_build_arg_xdr(struct svc_rqst *rqstp,
>   		sge_no++;
>   	}
>   	rqstp->rq_respages = &rqstp->rq_pages[sge_no];
> +	rqstp->rq_next_page = rqstp->rq_respages + 1;
This was fixed in an older version.
>   
>   	/* We should never run out of SGE because the limit is defined to
>   	 * support the max allowed RPC data length
> @@ -169,6 +170,7 @@ static int map_read_chunks(struct svcxprt_rdma *xprt,
>   		 */
>   		head->arg.pages[page_no] = rqstp->rq_arg.pages[page_no];
>   		rqstp->rq_respages = &rqstp->rq_arg.pages[page_no+1];
> +		rqstp->rq_next_page = rqstp->rq_respages + 1;
>   
>   		byte_count -= sge_bytes;
>   		ch_bytes -= sge_bytes;
> @@ -276,6 +278,7 @@ static int fast_reg_read_chunks(struct svcxprt_rdma *xprt,
>   
>   	/* rq_respages points one past arg pages */
>   	rqstp->rq_respages = &rqstp->rq_arg.pages[page_no];
> +	rqstp->rq_next_page = rqstp->rq_respages + 1;
>   
>   	/* Create the reply and chunk maps */
>   	offset = 0;
> @@ -520,13 +523,6 @@ next_sge:
>   	for (ch_no = 0; &rqstp->rq_pages[ch_no] < rqstp->rq_respages; ch_no++)
>   		rqstp->rq_pages[ch_no] = NULL;
>   
> -	/*
> -	 * Detach res pages. If svc_release sees any it will attempt to
> -	 * put them.
> -	 */
> -	while (rqstp->rq_next_page != rqstp->rq_respages)
> -		*(--rqstp->rq_next_page) = NULL;
> -
>   	return err;
>   }
>   
> @@ -550,7 +546,7 @@ static int rdma_read_complete(struct svc_rqst *rqstp,
>   
>   	/* rq_respages starts after the last arg page */
>   	rqstp->rq_respages = &rqstp->rq_arg.pages[page_no];
> -	rqstp->rq_next_page = &rqstp->rq_arg.pages[page_no];
> +	rqstp->rq_next_page = rqstp->rq_respages + 1;
>   
>   	/* Rebuild rq_arg head and tail. */
>   	rqstp->rq_arg.head[0] = head->arg.head[0];
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> index c1d124dc772b..11e90f8c0fc5 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> @@ -625,6 +625,7 @@ static int send_reply(struct svcxprt_rdma *rdma,
>   		if (page_no+1 >= sge_no)
>   			ctxt->sge[page_no+1].length = 0;
>   	}
> +	rqstp->rq_next_page = rqstp->rq_respages + 1;
>   	BUG_ON(sge_no > rdma->sc_max_sge);
>   	memset(&send_wr, 0, sizeof send_wr);
>   	ctxt->wr_op = IB_WR_SEND;