1 files changed, 49 insertions, 0 deletions

diff --git a/net/9p/client.c b/net/9p/client.c
index f7e90b4769bb..00774656eeac 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -18,6 +18,7 @@
 #include <linux/sched/signal.h>
 #include <linux/uaccess.h>
 #include <linux/uio.h>
+#include <linux/netfs.h>
 #include <net/9p/9p.h>
 #include <linux/parser.h>
 #include <linux/seq_file.h>
@@ -1661,6 +1662,54 @@ p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
 }
 EXPORT_SYMBOL(p9_client_write);
 
+void
+p9_client_write_subreq(struct netfs_io_subrequest *subreq)
+{
+	struct netfs_io_request *wreq = subreq->rreq;
+	struct p9_fid *fid = wreq->netfs_priv;
+	struct p9_client *clnt = fid->clnt;
+	struct p9_req_t *req;
+	unsigned long long start = subreq->start + subreq->transferred;
+	int written, len = subreq->len - subreq->transferred;
+	int err;
+
+	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu len %d\n",
+		 fid->fid, start, len);
+
+	/* Don't bother zerocopy for small IO (< 1024) */
+	if (clnt->trans_mod->zc_request && len > 1024) {
+		req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, &subreq->io_iter,
+				       0, wreq->len, P9_ZC_HDR_SZ, "dqd",
+				       fid->fid, start, len);
+	} else {
+		req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
+				    start, len, &subreq->io_iter);
+	}
+	if (IS_ERR(req)) {
+		netfs_write_subrequest_terminated(subreq, PTR_ERR(req), false);
+		return;
+	}
+
+	err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &written);
+	if (err) {
+		trace_9p_protocol_dump(clnt, &req->rc);
+		p9_req_put(clnt, req);
+		netfs_write_subrequest_terminated(subreq, err, false);
+		return;
+	}
+
+	if (written > len) {
+		pr_err("bogus RWRITE count (%d > %u)\n", written, len);
+		written = len;
+	}
+
+	p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", len);
+
+	p9_req_put(clnt, req);
+	netfs_write_subrequest_terminated(subreq, written, false);
+}
+EXPORT_SYMBOL(p9_client_write_subreq);
+
 struct p9_wstat *p9_client_stat(struct p9_fid *fid)
 {
 	int err;