From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Venkateswararao Jujjuri (JV)" Subject: [RFC] [PATCH 1/7] [net/9p] Additional elements to p9_fcall to accomodate zero copy. Date: Sun, 6 Feb 2011 23:21:23 -0800 Message-ID: <1297063283-2180-8-git-send-email-jvrao@linux.vnet.ibm.com> References: <1297063283-2180-1-git-send-email-jvrao@linux.vnet.ibm.com> Cc: linux-fsdevel@vger.kernel.org, "Venkateswararao Jujjuri (JV)" To: v9fs-developer@lists.sourceforge.net Return-path: Received: from e37.co.us.ibm.com ([32.97.110.158]:50516 "EHLO e37.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752510Ab1BGGoa (ORCPT ); Mon, 7 Feb 2011 01:44:30 -0500 Received: from d03relay03.boulder.ibm.com (d03relay03.boulder.ibm.com [9.17.195.228]) by e37.co.us.ibm.com (8.14.4/8.13.1) with ESMTP id p176ftNv016473 for ; Sun, 6 Feb 2011 23:41:55 -0700 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay03.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p176iQiC122306 for ; Sun, 6 Feb 2011 23:44:26 -0700 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p176iPTM018178 for ; Sun, 6 Feb 2011 23:44:26 -0700 In-Reply-To: <1297063283-2180-1-git-send-email-jvrao@linux.vnet.ibm.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: In addition, this patch also avoids zero copy for short reads in !dotl case. Signed-off-by: Venkateswararao Jujjuri Conflicts: net/9p/protocol.c --- include/net/9p/9p.h | 2 + net/9p/client.c | 74 +++++++++++++++++++++++++++++++++----------------- 2 files changed, 51 insertions(+), 25 deletions(-) diff --git a/include/net/9p/9p.h b/include/net/9p/9p.h index 9c939c2..7313801 100644 --- a/include/net/9p/9p.h +++ b/include/net/9p/9p.h @@ -320,6 +320,8 @@ enum p9_qid_t { /* Room for readdir header */ #define P9_READDIRHDRSZ 24 +#define P9_ERRMAX 256 /* FIXME: Check what is the correct value */ + /** * struct p9_str - length prefixed string type * @len: length of the string diff --git a/net/9p/client.c b/net/9p/client.c index f939edf..7f34c42 100644 --- a/net/9p/client.c +++ b/net/9p/client.c @@ -443,6 +443,7 @@ static int p9_check_errors(struct p9_client *c, struct p9_req_t *req) { int8_t type; int err; + int ecode; err = p9_parse_header(req->rc, NULL, &type, NULL, 0); if (err) { @@ -450,36 +451,53 @@ static int p9_check_errors(struct p9_client *c, struct p9_req_t *req) return err; } - if (type == P9_RERROR || type == P9_RLERROR) { - int ecode; - - if (!p9_is_proto_dotl(c)) { - char *ename; + if (type != P9_RERROR && type != P9_RLERROR) + return 0; - err = p9pdu_readf(req->rc, c->proto_version, "s?d", - &ename, &ecode); - if (err) - goto out_err; + if (!p9_is_proto_dotl(c)) { + char *ename; + + if (req->tc->pbuf_size) { + /* Handle user buffers */ + size_t len = req->rc->size - req->rc->offset; + if (req->tc->pbuf && + !segment_eq(get_fs(), KERNEL_DS)) { + /* User Buffer */ + err = copy_from_user( + &req->rc->sdata[req->rc->offset], + req->tc->pbuf, len); + if (err) { + err = -EFAULT; + return err; + } + } else { + /* Kernel Buffer */ + memmove(&req->rc->sdata[req->rc->offset], + req->tc->pbuf, len); + } + } + err = p9pdu_readf(req->rc, c->proto_version, "s?d", + &ename, &ecode); + if (err) + goto out_err; - if (p9_is_proto_dotu(c)) - err = -ecode; + if (p9_is_proto_dotu(c)) + err = -ecode; - if (!err || !IS_ERR_VALUE(err)) { - err = p9_errstr2errno(ename, strlen(ename)); + if (!err || !IS_ERR_VALUE(err)) { + err = p9_errstr2errno(ename, strlen(ename)); - P9_DPRINTK(P9_DEBUG_9P, "<<< RERROR (%d) %s\n", -ecode, ename); + P9_DPRINTK(P9_DEBUG_9P, "<<< RERROR (%d) %s\n", -ecode, ename); - kfree(ename); - } - } else { - err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode); - err = -ecode; - - P9_DPRINTK(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode); + kfree(ename); } + } else { + err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode); + err = -ecode; + + P9_DPRINTK(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode); + } - } else - err = 0; return err; @@ -1270,8 +1288,14 @@ p9_client_read(struct p9_fid *fid, char *data, char __user *udata, u64 offset, if (count < rsize) rsize = count; - if ((clnt->trans_mod->pref & P9_TRANS_PREF_PAYLOAD_MASK) == - P9_TRANS_PREF_PAYLOAD_SEP) { + /* for !p9_proto_2000L, we need to have enough space on PDU + * to handle TREAD/RERROR. Hence don't attempt payload + * seperaion for small reads even if the transport prefers + * P9_TRANS_PREF_PAYLOAD_SEP */ + if (((clnt->trans_mod->pref & P9_TRANS_PREF_PAYLOAD_MASK) == + P9_TRANS_PREF_PAYLOAD_SEP) && + ((clnt->proto_version == p9_proto_2000L) || + rsize > 2 * P9_ERRMAX) ) { req = p9_client_rpc(clnt, P9_TREAD, "dqE", fid->fid, offset, rsize, data ? data : udata); } else { -- 1.6.5.2