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[68.61.232.219]) by smtp.gmail.com with ESMTPSA id w204sm14980202qka.41.2020.06.22.14.01.05 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 22 Jun 2020 14:01:06 -0700 (PDT) Received: from klimt.1015granger.net (klimt.1015granger.net [192.168.1.55]) by gateway.1015granger.net (8.14.7/8.14.7) with ESMTP id 05ML15cQ018822; Mon, 22 Jun 2020 21:01:05 GMT Subject: [PATCH v1 1/6] svcrdma: Fix page leak in svc_rdma_recv_read_chunk() From: Chuck Lever To: linux-nfs@vger.kernel.org, linux-rdma@vger.kernel.org Date: Mon, 22 Jun 2020 17:01:05 -0400 Message-ID: <20200622210105.2144.36726.stgit@klimt.1015granger.net> In-Reply-To: <20200622205906.2144.43930.stgit@klimt.1015granger.net> References: <20200622205906.2144.43930.stgit@klimt.1015granger.net> User-Agent: StGit/0.22-31-g4b47 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org Commit 07d0ff3b0cd2 ("svcrdma: Clean up Read chunk path") moved the page saver logic so that it gets executed event when an error occurs. In that case, the I/O is never posted, and those pages are then leaked. Errors in this path, however, are quite rare. Fixes: 07d0ff3b0cd2 ("svcrdma: Clean up Read chunk path") Signed-off-by: Chuck Lever --- net/sunrpc/xprtrdma/svc_rdma_rw.c | 28 +++++++++++++++++++++------- 1 file changed, 21 insertions(+), 7 deletions(-) diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c index 5eb35309ecef..83806fa94def 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_rw.c +++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c @@ -684,7 +684,6 @@ static int svc_rdma_build_read_chunk(struct svc_rqst *rqstp, struct svc_rdma_read_info *info, __be32 *p) { - unsigned int i; int ret; ret = -EINVAL; @@ -707,12 +706,6 @@ static int svc_rdma_build_read_chunk(struct svc_rqst *rqstp, info->ri_chunklen += rs_length; } - /* Pages under I/O have been copied to head->rc_pages. - * Prevent their premature release by svc_xprt_release() . - */ - for (i = 0; i < info->ri_readctxt->rc_page_count; i++) - rqstp->rq_pages[i] = NULL; - return ret; } @@ -807,6 +800,26 @@ static int svc_rdma_build_pz_read_chunk(struct svc_rqst *rqstp, return ret; } +/* Pages under I/O have been copied to head->rc_pages. Ensure they + * are not released by svc_xprt_release() until the I/O is complete. + * + * This has to be done after all Read WRs are constructed to properly + * handle a page that is part of I/O on behalf of two different RDMA + * segments. + * + * Do this only if I/O has been posted. Otherwise, we do indeed want + * svc_xprt_release() to clean things up properly. + */ +static void svc_rdma_save_io_pages(struct svc_rqst *rqstp, + const unsigned int start, + const unsigned int num_pages) +{ + unsigned int i; + + for (i = start; i < num_pages + start; i++) + rqstp->rq_pages[i] = NULL; +} + /** * svc_rdma_recv_read_chunk - Pull a Read chunk from the client * @rdma: controlling RDMA transport @@ -860,6 +873,7 @@ int svc_rdma_recv_read_chunk(struct svcxprt_rdma *rdma, struct svc_rqst *rqstp, ret = svc_rdma_post_chunk_ctxt(&info->ri_cc); if (ret < 0) goto out_err; + svc_rdma_save_io_pages(rqstp, 0, head->rc_page_count); return 0; out_err: