From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D1E96C43334 for ; Fri, 1 Jul 2022 13:47:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231555AbiGANrc (ORCPT ); Fri, 1 Jul 2022 09:47:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40980 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231557AbiGANrb (ORCPT ); Fri, 1 Jul 2022 09:47:31 -0400 Received: from kylie.crudebyte.com (kylie.crudebyte.com [5.189.157.229]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 033102252F for ; Fri, 1 Jul 2022 06:47:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=crudebyte.com; s=kylie; h=Content-Type:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Content-ID:Content-Description; bh=Go8HaF3VoPFHkP1B+Cs94du0xGeGCJofe/qVsbIPjkI=; b=P+Ok4CmVFAuqyeWMyzkEVmSGmN v2npl2aO+/twyehOX6N73lfvkARlPcAMKx+vIaELSTRMGLNkNy6PDgBmereWviFoRLvUgR+a1UqpK Zl0aMBja+btfhJhNoIkCqhUWpbJJ+euffRYv8EJOOIpotpm7SY6jIwTwJ9hRbyCmHYO31wOenNwXU EE3CtHjq4+vJn9ovTh1VucmdIYc7otyiuKpnS/HddRNR1nyr8A3VvOca+DEFHV5+ruk5NNk7eBHHY p26IXmIbZEYyiGCMfP3UkBdjURvpGXhpm00jIctQFMn6yiOdxdYmAkoZ8etA34DO8xXobMaIgajgE UR1aBYpvchUTHo7z1dlZqtce9+7t3pMUrPd6+o7faJAyVqT0j5P/wlZ5bbQkFXFyH50TSAJbKSIV2 OjCxwdwLjBvWxvB/dM+ylMO0Akra3PFiUmVz0MzvMoHD1OCosd2JQ9yO1Jm6KCw5o9pxBwXdUWfXm Wdl2JrUUtCT853x0iEKU8dyJ+18WD0kMAd5U8GV5AeANVN7UQT2kTHXzZom7n4RmsDIqzvGzaODil +1zQxUH5rQSDEN07KKx5EdbkqXjPbiqd6fL/VuB47Mg/0YIm0BXNgcutzCLVpHkAxdbZXIsjfq3OP CIpapsct0BUIZeuUkc23CGgVRM98yvfja3f9D7OOg=; From: Christian Schoenebeck To: linux-fsdevel@vger.kernel.org, Al Viro , Dominique Martinet Cc: Linus Torvalds , Jens Axboe , Christoph Hellwig , Matthew Wilcox , David Howells , Christian Brauner Subject: Re: [PATCH 40/44] 9p: convert to advancing variant of iov_iter_get_pages_alloc() Date: Fri, 01 Jul 2022 15:47:24 +0200 Message-ID: <7966323.F5XntFNgCk@silver> In-Reply-To: <20220622041552.737754-40-viro@zeniv.linux.org.uk> References: <20220622041552.737754-1-viro@zeniv.linux.org.uk> <20220622041552.737754-40-viro@zeniv.linux.org.uk> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mittwoch, 22. Juni 2022 06:15:48 CEST Al Viro wrote: > that one is somewhat clumsier than usual and needs serious testing. > > Signed-off-by: Al Viro Hi Al, it took me a bit to find the patch that introduces iov_iter_get_pages_alloc2(), but this patch itself looks fine: Reviewed-by: Christian Schoenebeck Please give me some days for thorough testing. We recently had 9p broken (with cache=loose) for half a year, so I would like to avoid repetition. Best regards, Christian Schoenebeck > --- > net/9p/client.c | 39 +++++++++++++++++++++++---------------- > net/9p/protocol.c | 3 +-- > net/9p/trans_virtio.c | 3 ++- > 3 files changed, 26 insertions(+), 19 deletions(-) > > diff --git a/net/9p/client.c b/net/9p/client.c > index d403085b9ef5..cb4324211561 100644 > --- a/net/9p/client.c > +++ b/net/9p/client.c > @@ -1491,7 +1491,7 @@ p9_client_read_once(struct p9_fid *fid, u64 offset, > struct iov_iter *to, struct p9_client *clnt = fid->clnt; > struct p9_req_t *req; > int count = iov_iter_count(to); > - int rsize, non_zc = 0; > + int rsize, received, non_zc = 0; > char *dataptr; > > *err = 0; > @@ -1520,36 +1520,40 @@ p9_client_read_once(struct p9_fid *fid, u64 offset, > struct iov_iter *to, } > if (IS_ERR(req)) { > *err = PTR_ERR(req); > + if (!non_zc) > + iov_iter_revert(to, count - iov_iter_count(to)); > return 0; > } > > *err = p9pdu_readf(&req->rc, clnt->proto_version, > - "D", &count, &dataptr); > + "D", &received, &dataptr); > if (*err) { > + if (!non_zc) > + iov_iter_revert(to, count - iov_iter_count(to)); > trace_9p_protocol_dump(clnt, &req->rc); > p9_tag_remove(clnt, req); > return 0; > } > - if (rsize < count) { > - pr_err("bogus RREAD count (%d > %d)\n", count, rsize); > - count = rsize; > + if (rsize < received) { > + pr_err("bogus RREAD count (%d > %d)\n", received, rsize); > + received = rsize; > } > > p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count); > > if (non_zc) { > - int n = copy_to_iter(dataptr, count, to); > + int n = copy_to_iter(dataptr, received, to); > > - if (n != count) { > + if (n != received) { > *err = -EFAULT; > p9_tag_remove(clnt, req); > return n; > } > } else { > - iov_iter_advance(to, count); > + iov_iter_revert(to, count - received - iov_iter_count(to)); > } > p9_tag_remove(clnt, req); > - return count; > + return received; > } > EXPORT_SYMBOL(p9_client_read_once); > > @@ -1567,6 +1571,7 @@ p9_client_write(struct p9_fid *fid, u64 offset, struct > iov_iter *from, int *err) while (iov_iter_count(from)) { > int count = iov_iter_count(from); > int rsize = fid->iounit; > + int written; > > if (!rsize || rsize > clnt->msize - P9_IOHDRSZ) > rsize = clnt->msize - P9_IOHDRSZ; > @@ -1584,27 +1589,29 @@ p9_client_write(struct p9_fid *fid, u64 offset, > struct iov_iter *from, int *err) offset, rsize, from); > } > if (IS_ERR(req)) { > + iov_iter_revert(from, count - iov_iter_count(from)); > *err = PTR_ERR(req); > break; > } > > - *err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &count); > + *err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &written); > if (*err) { > + iov_iter_revert(from, count - iov_iter_count(from)); > trace_9p_protocol_dump(clnt, &req->rc); > p9_tag_remove(clnt, req); > break; > } > - if (rsize < count) { > - pr_err("bogus RWRITE count (%d > %d)\n", count, rsize); > - count = rsize; > + if (rsize < written) { > + pr_err("bogus RWRITE count (%d > %d)\n", written, rsize); > + written = rsize; > } > > p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count); > > p9_tag_remove(clnt, req); > - iov_iter_advance(from, count); > - total += count; > - offset += count; > + iov_iter_revert(from, count - written - iov_iter_count(from)); > + total += written; > + offset += written; > } > return total; > } > diff --git a/net/9p/protocol.c b/net/9p/protocol.c > index 3754c33e2974..83694c631989 100644 > --- a/net/9p/protocol.c > +++ b/net/9p/protocol.c > @@ -63,9 +63,8 @@ static size_t > pdu_write_u(struct p9_fcall *pdu, struct iov_iter *from, size_t size) > { > size_t len = min(pdu->capacity - pdu->size, size); > - struct iov_iter i = *from; > > - if (!copy_from_iter_full(&pdu->sdata[pdu->size], len, &i)) > + if (!copy_from_iter_full(&pdu->sdata[pdu->size], len, from)) > len = 0; > > pdu->size += len; > diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c > index 2a210c2f8e40..1977d33475fe 100644 > --- a/net/9p/trans_virtio.c > +++ b/net/9p/trans_virtio.c > @@ -331,7 +331,7 @@ static int p9_get_mapped_pages(struct virtio_chan *chan, > if (err == -ERESTARTSYS) > return err; > } > - n = iov_iter_get_pages_alloc(data, pages, count, offs); > + n = iov_iter_get_pages_alloc2(data, pages, count, offs); > if (n < 0) > return n; > *need_drop = 1; > @@ -373,6 +373,7 @@ static int p9_get_mapped_pages(struct virtio_chan *chan, > (*pages)[index] = kmap_to_page(p); > p += PAGE_SIZE; > } > + iov_iter_advance(data, len); > return len; > } > }