netfs: Move max_len/max_nr_segs from netfs_io_subrequest to netfs_io_stream

Move max_len/max_nr_segs from struct netfs_io_subrequest to struct
netfs_io_stream as we only issue one subreq at a time and then don't need
these values again for that subreq unless and until we have to retry it -
in which case we want to renegotiate them.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20240814203850.2240469-8-dhowells@redhat.com/ # v2
Signed-off-by: Christian Brauner <brauner@kernel.org>

fs/afs/write.c

@@ -89,10 +89,12 @@ static const struct afs_operation_ops afs_store_data_operation = {
  */
 void afs_prepare_write(struct netfs_io_subrequest *subreq)
 {
+	struct netfs_io_stream *stream = &subreq->rreq->io_streams[subreq->stream_nr];
+
 	//if (test_bit(NETFS_SREQ_RETRYING, &subreq->flags))
 	//	subreq->max_len = 512 * 1024;
 	//else
-	subreq->max_len = 256 * 1024 * 1024;
+	stream->sreq_max_len = 256 * 1024 * 1024;
 }
 
 /*

fs/cachefiles/io.c

@@ -627,11 +627,12 @@ static void cachefiles_prepare_write_subreq(struct netfs_io_subrequest *subreq)
 {
 	struct netfs_io_request *wreq = subreq->rreq;
 	struct netfs_cache_resources *cres = &wreq->cache_resources;
+	struct netfs_io_stream *stream = &wreq->io_streams[subreq->stream_nr];
 
 	_enter("W=%x[%x] %llx", wreq->debug_id, subreq->debug_index, subreq->start);
 
-	subreq->max_len = MAX_RW_COUNT;
+	stream->sreq_max_len = MAX_RW_COUNT;
-	subreq->max_nr_segs = BIO_MAX_VECS;
+	stream->sreq_max_segs = BIO_MAX_VECS;
 
 	if (!cachefiles_cres_file(cres)) {
 		if (!fscache_wait_for_operation(cres, FSCACHE_WANT_WRITE))

fs/netfs/io.c

@@ -624,9 +624,9 @@ netfs_rreq_prepare_read(struct netfs_io_request *rreq,
 			goto out;
 		}
 
-		if (subreq->max_nr_segs) {
+		if (rreq->io_streams[0].sreq_max_segs) {
 			lsize = netfs_limit_iter(io_iter, 0, subreq->len,
-						 subreq->max_nr_segs);
+						 rreq->io_streams[0].sreq_max_segs);
 			if (subreq->len > lsize) {
 				subreq->len = lsize;
 				trace_netfs_sreq(subreq, netfs_sreq_trace_limited);

fs/netfs/write_collect.c

@@ -238,7 +238,7 @@ static void netfs_retry_write_stream(struct netfs_io_request *wreq,
 			__set_bit(NETFS_SREQ_RETRYING, &subreq->flags);
 			stream->prepare_write(subreq);
 
-			part = min(len, subreq->max_len);
+			part = min(len, stream->sreq_max_len);
 			subreq->len = part;
 			subreq->start = start;
 			subreq->transferred = 0;
@@ -278,8 +278,6 @@ static void netfs_retry_write_stream(struct netfs_io_request *wreq,
 			subreq = netfs_alloc_subrequest(wreq);
 			subreq->source		= to->source;
 			subreq->start		= start;
-			subreq->max_len		= len;
-			subreq->max_nr_segs	= INT_MAX;
 			subreq->debug_index	= atomic_inc_return(&wreq->subreq_counter);
 			subreq->stream_nr	= to->stream_nr;
 			__set_bit(NETFS_SREQ_RETRYING, &subreq->flags);
@@ -293,10 +291,12 @@ static void netfs_retry_write_stream(struct netfs_io_request *wreq,
 			to = list_next_entry(to, rreq_link);
 			trace_netfs_sreq(subreq, netfs_sreq_trace_retry);
 
+			stream->sreq_max_len	= len;
+			stream->sreq_max_segs	= INT_MAX;
 			switch (stream->source) {
 			case NETFS_UPLOAD_TO_SERVER:
 				netfs_stat(&netfs_n_wh_upload);
-				subreq->max_len = min(len, wreq->wsize);
+				stream->sreq_max_len = umin(len, wreq->wsize);
 				break;
 			case NETFS_WRITE_TO_CACHE:
 				netfs_stat(&netfs_n_wh_write);
@@ -307,7 +307,7 @@ static void netfs_retry_write_stream(struct netfs_io_request *wreq,
 
 			stream->prepare_write(subreq);
 
-			part = min(len, subreq->max_len);
+			part = umin(len, stream->sreq_max_len);
 			subreq->len = subreq->transferred + part;
 			len -= part;
 			start += part;

fs/netfs/write_issue.c

@@ -158,8 +158,6 @@ static void netfs_prepare_write(struct netfs_io_request *wreq,
 	subreq = netfs_alloc_subrequest(wreq);
 	subreq->source		= stream->source;
 	subreq->start		= start;
-	subreq->max_len		= ULONG_MAX;
-	subreq->max_nr_segs	= INT_MAX;
 	subreq->stream_nr	= stream->stream_nr;
 
 	_enter("R=%x[%x]", wreq->debug_id, subreq->debug_index);
@@ -170,10 +168,12 @@ static void netfs_prepare_write(struct netfs_io_request *wreq,
 
 	trace_netfs_sreq(subreq, netfs_sreq_trace_prepare);
 
+	stream->sreq_max_len	= UINT_MAX;
+	stream->sreq_max_segs	= INT_MAX;
 	switch (stream->source) {
 	case NETFS_UPLOAD_TO_SERVER:
 		netfs_stat(&netfs_n_wh_upload);
-		subreq->max_len = wreq->wsize;
+		stream->sreq_max_len = wreq->wsize;
 		break;
 	case NETFS_WRITE_TO_CACHE:
 		netfs_stat(&netfs_n_wh_write);
@@ -290,13 +290,13 @@ int netfs_advance_write(struct netfs_io_request *wreq,
 		netfs_prepare_write(wreq, stream, start);
 	subreq = stream->construct;
 
-	part = min(subreq->max_len - subreq->len, len);
+	part = umin(stream->sreq_max_len - subreq->len, len);
-	_debug("part %zx/%zx %zx/%zx", subreq->len, subreq->max_len, part, len);
+	_debug("part %zx/%zx %zx/%zx", subreq->len, stream->sreq_max_len, part, len);
 	subreq->len += part;
 	subreq->nr_segs++;
 
-	if (subreq->len >= subreq->max_len ||
+	if (subreq->len >= stream->sreq_max_len ||
-	    subreq->nr_segs >= subreq->max_nr_segs ||
+	    subreq->nr_segs >= stream->sreq_max_segs ||
 	    to_eof) {
 		netfs_issue_write(wreq, stream);
 		subreq = NULL;

fs/smb/client/file.c

@@ -49,6 +49,7 @@ static void cifs_prepare_write(struct netfs_io_subrequest *subreq)
 	struct cifs_io_subrequest *wdata =
 		container_of(subreq, struct cifs_io_subrequest, subreq);
 	struct cifs_io_request *req = wdata->req;
+	struct netfs_io_stream *stream = &req->rreq.io_streams[subreq->stream_nr];
 	struct TCP_Server_Info *server;
 	struct cifsFileInfo *open_file = req->cfile;
 	size_t wsize = req->rreq.wsize;
@@ -73,7 +74,7 @@ retry:
 		}
 	}
 
-	rc = server->ops->wait_mtu_credits(server, wsize, &wdata->subreq.max_len,
+	rc = server->ops->wait_mtu_credits(server, wsize, &stream->sreq_max_len,
 					   &wdata->credits);
 	if (rc < 0) {
 		subreq->error = rc;
@@ -92,7 +93,7 @@ retry:
 
 #ifdef CONFIG_CIFS_SMB_DIRECT
 	if (server->smbd_conn)
-		subreq->max_nr_segs = server->smbd_conn->max_frmr_depth;
+		stream->sreq_max_segs = server->smbd_conn->max_frmr_depth;
 #endif
 }
 
@@ -150,11 +151,11 @@ static void cifs_netfs_invalidate_cache(struct netfs_io_request *wreq)
 static bool cifs_clamp_length(struct netfs_io_subrequest *subreq)
 {
 	struct netfs_io_request *rreq = subreq->rreq;
+	struct netfs_io_stream *stream = &rreq->io_streams[subreq->stream_nr];
 	struct cifs_io_subrequest *rdata = container_of(subreq, struct cifs_io_subrequest, subreq);
 	struct cifs_io_request *req = container_of(subreq->rreq, struct cifs_io_request, rreq);
 	struct TCP_Server_Info *server = req->server;
 	struct cifs_sb_info *cifs_sb = CIFS_SB(rreq->inode->i_sb);
-	size_t rsize;
 	int rc;
 
 	rdata->xid = get_xid();
@@ -168,7 +169,7 @@ static bool cifs_clamp_length(struct netfs_io_subrequest *subreq)
 
 
 	rc = server->ops->wait_mtu_credits(server, cifs_sb->ctx->rsize,
-					   &rsize, &rdata->credits);
+					   &stream->sreq_max_len, &rdata->credits);
 	if (rc) {
 		subreq->error = rc;
 		return false;
@@ -184,12 +185,12 @@ static bool cifs_clamp_length(struct netfs_io_subrequest *subreq)
 			      server->credits, server->in_flight, 0,
 			      cifs_trace_rw_credits_read_submit);
 
-	subreq->len = umin(subreq->len, rsize);
+	subreq->len = umin(subreq->len, stream->sreq_max_len);
 	rdata->actual_len = subreq->len;
 
 #ifdef CONFIG_CIFS_SMB_DIRECT
 	if (server->smbd_conn)
-		subreq->max_nr_segs = server->smbd_conn->max_frmr_depth;
+		stream->sreq_max_segs = server->smbd_conn->max_frmr_depth;
 #endif
 	return true;
 }

include/linux/netfs.h

@@ -134,6 +134,8 @@ static inline struct netfs_group *netfs_folio_group(struct folio *folio)
 struct netfs_io_stream {
 	/* Submission tracking */
 	struct netfs_io_subrequest *construct;	/* Op being constructed */
+	size_t			sreq_max_len;	/* Maximum size of a subrequest */
+	unsigned int		sreq_max_segs;	/* 0 or max number of segments in an iterator */
 	unsigned int		submit_off;	/* Folio offset we're submitting from */
 	unsigned int		submit_len;	/* Amount of data left to submit */
 	unsigned int		submit_max_len;	/* Amount I/O can be rounded up to */
@@ -177,14 +179,12 @@ struct netfs_io_subrequest {
 	struct list_head	rreq_link;	/* Link in rreq->subrequests */
 	struct iov_iter		io_iter;	/* Iterator for this subrequest */
 	unsigned long long	start;		/* Where to start the I/O */
-	size_t			max_len;	/* Maximum size of the I/O */
 	size_t			len;		/* Size of the I/O */
 	size_t			transferred;	/* Amount of data transferred */
 	refcount_t		ref;
 	short			error;		/* 0 or error that occurred */
 	unsigned short		debug_index;	/* Index in list (for debugging output) */
 	unsigned int		nr_segs;	/* Number of segs in io_iter */
-	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 char		stream_nr;	/* I/O stream this belongs to */
 	unsigned long		flags;