fs/netfs: remove unused flag NETFS_RREQ_DONT_UNLOCK_FOLIOS

NETFS_RREQ_DONT_UNLOCK_FOLIOS has never been used ever since it was
added by commit 3d3c950 ("netfs: Provide readahead and readpage
netfs helpers").

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/20250519134813.2975312-11-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.com>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: MaxKellermann

fs/netfs/read_collect.c

@@ -83,14 +83,12 @@ static void netfs_unlock_read_folio(struct netfs_io_request *rreq,
 	}
 
 just_unlock:
-	if (!test_bit(NETFS_RREQ_DONT_UNLOCK_FOLIOS, &rreq->flags)) {
-		if (folio->index == rreq->no_unlock_folio &&
-		    test_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags)) {
-			_debug("no unlock");
-		} else {
-			trace_netfs_folio(folio, netfs_folio_trace_read_unlock);
-			folio_unlock(folio);
-		}
+	if (folio->index == rreq->no_unlock_folio &&
+	    test_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags)) {
+		_debug("no unlock");
+	} else {
+		trace_netfs_folio(folio, netfs_folio_trace_read_unlock);
+		folio_unlock(folio);
 	}
 
 	folioq_clear(folioq, slot);

include/linux/netfs.h

@@ -266,7 +266,6 @@ struct netfs_io_request {
 	unsigned long		flags;
 #define NETFS_RREQ_OFFLOAD_COLLECTION	0	/* Offload collection to workqueue */
 #define NETFS_RREQ_NO_UNLOCK_FOLIO	2	/* Don't unlock no_unlock_folio on completion */
-#define NETFS_RREQ_DONT_UNLOCK_FOLIOS	3	/* Don't unlock the folios on completion */
 #define NETFS_RREQ_FAILED		4	/* The request failed */
 #define NETFS_RREQ_IN_PROGRESS		5	/* Unlocked when the request completes */
 #define NETFS_RREQ_FOLIO_COPY_TO_CACHE	6	/* Copy current folio to cache from read */