linux-kernel - [PATCH v2 09/17] cifs: Defer read completion

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Message-ID: <612371.1718911800@warthog.procyon.org.uk>
Date: Thu, 20 Jun 2024 20:30:00 +0100
From: David Howells <dhowells@...hat.com>
Cc: dhowells@...hat.com, Christian Brauner <christian@...uner.io>,
    Steve French <smfrench@...il.com>,
    Matthew Wilcox <willy@...radead.org>,
    Jeff Layton <jlayton@...nel.org>,
    Gao Xiang <hsiangkao@...ux.alibaba.com>,
    Dominique Martinet <asmadeus@...ewreck.org>,
    Marc Dionne <marc.dionne@...istor.com>,
    Paulo Alcantara <pc@...guebit.com>,
    Shyam Prasad N <sprasad@...rosoft.com>, Tom Talpey <tom@...pey.com>,
    Eric Van Hensbergen <ericvh@...nel.org>,
    Ilya Dryomov <idryomov@...il.com>, netfs@...ts.linux.dev,
    linux-afs@...ts.infradead.org, linux-cifs@...r.kernel.org,
    linux-nfs@...r.kernel.org, ceph-devel@...r.kernel.org,
    v9fs@...ts.linux.dev, linux-erofs@...ts.ozlabs.org,
    linux-fsdevel@...r.kernel.org, linux-mm@...ck.org,
    netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2 09/17] cifs: Defer read completion

Oops - a bit of debugging code had got left in this patch and I forgot to
fill out the description.  Updated patch attached.

David
---
cifs: Defer read completion

Defer read completion from the I/O thread to the cifsiod thread so as not
to slow down the I/O thread.  This restores the behaviour of v6.9.

Signed-off-by: David Howells <dhowells@...hat.com>
cc: Steve French <sfrench@...ba.org>
cc: Paulo Alcantara <pc@...guebit.com>
cc: Jeff Layton <jlayton@...nel.org>
cc: linux-cifs@...r.kernel.org
cc: netfs@...ts.linux.dev
cc: linux-fsdevel@...r.kernel.org
---
 fs/smb/client/smb2pdu.c |   15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index 38a06e8a0f90..e213cecd5094 100644
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -4484,6 +4484,16 @@ smb2_new_read_req(void **buf, unsigned int *total_len,
 	return rc;
 }
 
+static void smb2_readv_worker(struct work_struct *work)
+{
+	struct cifs_io_subrequest *rdata =
+		container_of(work, struct cifs_io_subrequest, subreq.work);
+
+	netfs_subreq_terminated(&rdata->subreq,
+				(rdata->result == 0 || rdata->result == -EAGAIN) ?
+				rdata->got_bytes : rdata->result, true);
+}
+
 static void
 smb2_readv_callback(struct mid_q_entry *mid)
 {
@@ -4578,9 +4588,8 @@ smb2_readv_callback(struct mid_q_entry *mid)
 			rdata->result = 0;
 	}
 	rdata->credits.value = 0;
-	netfs_subreq_terminated(&rdata->subreq,
-				(rdata->result == 0 || rdata->result == -EAGAIN) ?
-				rdata->got_bytes : rdata->result, true);
+	INIT_WORK(&rdata->subreq.work, smb2_readv_worker);
+	queue_work(cifsiod_wq, &rdata->subreq.work);
 	release_mid(mid);
 	add_credits(server, &credits, 0);
 }