From patchwork Wed Dec 13 15:23:27 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 13491263 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ZC/jQUV+" Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4EEBE1700 for ; Wed, 13 Dec 2023 07:25:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1702481116; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=YJNYoDwT7ftU812GMv/DOgXVSH8Cj0I5WKRdeJiGu3I=; b=ZC/jQUV+EwS6snYfTNqF+TGgdXRyzFclwE1aa2QS1xGvKU4vo7mjyRly3Gyk0zUsYFGWI7 OAseGkxBaQsVvHh0ngNcOA/EkG+EIbga0L96LaSqra45sYueaKGRtzrsaGxz3WVXa3xBYe M0zlGF1gdBiLRjvgddnaGC1YFq2jdEs= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-441-flG4pN2DMa-Hpy2vCSDm9Q-1; Wed, 13 Dec 2023 10:25:11 -0500 X-MC-Unique: flG4pN2DMa-Hpy2vCSDm9Q-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D07A71C06E02; Wed, 13 Dec 2023 15:25:06 +0000 (UTC) Received: from warthog.procyon.org.com (unknown [10.42.28.2]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3FA05492BC8; Wed, 13 Dec 2023 15:25:03 +0000 (UTC) From: David Howells To: Jeff Layton , Steve French Cc: David Howells , Matthew Wilcox , Marc Dionne , Paulo Alcantara , Shyam Prasad N , Tom Talpey , Dominique Martinet , Eric Van Hensbergen , Ilya Dryomov , Christian Brauner , linux-cachefs@redhat.com, linux-afs@lists.infradead.org, linux-cifs@vger.kernel.org, linux-nfs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 17/39] netfs: Limit subrequest by size or number of segments Date: Wed, 13 Dec 2023 15:23:27 +0000 Message-ID: <20231213152350.431591-18-dhowells@redhat.com> In-Reply-To: <20231213152350.431591-1-dhowells@redhat.com> References: <20231213152350.431591-1-dhowells@redhat.com> Precedence: bulk X-Mailing-List: ceph-devel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.9 Limit a subrequest to a maximum size and/or a maximum number of contiguous physical regions. This permits, for instance, an subreq's iterator to be limited to the number of DMA'able segments that a large RDMA request can handle. Signed-off-by: David Howells cc: Jeff Layton cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org --- fs/netfs/io.c | 18 ++++++++++++++++++ include/linux/netfs.h | 1 + include/trace/events/netfs.h | 1 + 3 files changed, 20 insertions(+) diff --git a/fs/netfs/io.c b/fs/netfs/io.c index d8e9cd6ce338..c80b8eed1209 100644 --- a/fs/netfs/io.c +++ b/fs/netfs/io.c @@ -525,6 +525,7 @@ netfs_rreq_prepare_read(struct netfs_io_request *rreq, struct iov_iter *io_iter) { enum netfs_io_source source; + size_t lsize; _enter("%llx-%llx,%llx", subreq->start, subreq->start + subreq->len, rreq->i_size); @@ -547,13 +548,30 @@ netfs_rreq_prepare_read(struct netfs_io_request *rreq, source = NETFS_INVALID_READ; goto out; } + + if (subreq->max_nr_segs) { + lsize = netfs_limit_iter(io_iter, 0, subreq->len, + subreq->max_nr_segs); + if (subreq->len > lsize) { + subreq->len = lsize; + trace_netfs_sreq(subreq, netfs_sreq_trace_limited); + } + } } + if (subreq->len > rreq->len) + pr_warn("R=%08x[%u] SREQ>RREQ %zx > %zx\n", + rreq->debug_id, subreq->debug_index, + subreq->len, rreq->len); + if (WARN_ON(subreq->len == 0)) { source = NETFS_INVALID_READ; goto out; } + subreq->source = source; + trace_netfs_sreq(subreq, netfs_sreq_trace_prepare); + subreq->io_iter = *io_iter; iov_iter_truncate(&subreq->io_iter, subreq->len); iov_iter_advance(io_iter, subreq->len); diff --git a/include/linux/netfs.h b/include/linux/netfs.h index a30b47e10797..406d5a3a3298 100644 --- a/include/linux/netfs.h +++ b/include/linux/netfs.h @@ -161,6 +161,7 @@ struct netfs_io_subrequest { refcount_t ref; short error; /* 0 or error that occurred */ unsigned short debug_index; /* Index in list (for debugging output) */ + unsigned int max_nr_segs; /* 0 or max number of segments in an iterator */ enum netfs_io_source source; /* Where to read from/write to */ unsigned long flags; #define NETFS_SREQ_COPY_TO_CACHE 0 /* Set if should copy the data to the cache */ diff --git a/include/trace/events/netfs.h b/include/trace/events/netfs.h index beec534cbaab..fce6d0bc78e5 100644 --- a/include/trace/events/netfs.h +++ b/include/trace/events/netfs.h @@ -44,6 +44,7 @@ #define netfs_sreq_traces \ EM(netfs_sreq_trace_download_instead, "RDOWN") \ EM(netfs_sreq_trace_free, "FREE ") \ + EM(netfs_sreq_trace_limited, "LIMIT") \ EM(netfs_sreq_trace_prepare, "PREP ") \ EM(netfs_sreq_trace_resubmit_short, "SHORT") \ EM(netfs_sreq_trace_submit, "SUBMT") \