netfs: Use subreq_counter to allocate subreq debug_index values

Use the subreq_counter in netfs_io_request to allocate subrequest
debug_index values in read ops as well as write ops.

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

fs/netfs/io.c

@@ -501,8 +501,7 @@ netfs_rreq_prepare_read(struct netfs_io_request *rreq,
  * Slice off a piece of a read request and submit an I/O request for it.
  */
 static bool netfs_rreq_submit_slice(struct netfs_io_request *rreq,
-				    struct iov_iter *io_iter,
-				    unsigned int *_debug_index)
+				    struct iov_iter *io_iter)
 {
 	struct netfs_io_subrequest *subreq;
 	enum netfs_io_source source;
@@ -511,7 +510,6 @@ static bool netfs_rreq_submit_slice(struct netfs_io_request *rreq,
 	if (!subreq)
 		return false;
 
-	subreq->debug_index	= (*_debug_index)++;
 	subreq->start		= rreq->start + rreq->submitted;
 	subreq->len		= io_iter->count;
 
@@ -565,7 +563,6 @@ static bool netfs_rreq_submit_slice(struct netfs_io_request *rreq,
 int netfs_begin_read(struct netfs_io_request *rreq, bool sync)
 {
 	struct iov_iter io_iter;
-	unsigned int debug_index = 0;
 	int ret;
 
 	_enter("R=%x %llx-%llx",
@@ -596,7 +593,7 @@ int netfs_begin_read(struct netfs_io_request *rreq, bool sync)
 		if (rreq->origin == NETFS_DIO_READ &&
 		    rreq->start + rreq->submitted >= rreq->i_size)
 			break;
-		if (!netfs_rreq_submit_slice(rreq, &io_iter, &debug_index))
+		if (!netfs_rreq_submit_slice(rreq, &io_iter))
 			break;
 		if (test_bit(NETFS_RREQ_BLOCKED, &rreq->flags) &&
 		    test_bit(NETFS_RREQ_NONBLOCK, &rreq->flags))

fs/netfs/objects.c

@@ -152,6 +152,7 @@ struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq
 		INIT_LIST_HEAD(&subreq->rreq_link);
 		refcount_set(&subreq->ref, 2);
 		subreq->rreq = rreq;
+		subreq->debug_index = atomic_inc_return(&rreq->subreq_counter);
 		netfs_get_request(rreq, netfs_rreq_trace_get_subreq);
 		netfs_stat(&netfs_n_rh_sreq);
 	}

fs/netfs/output.c

@@ -37,7 +37,6 @@ struct netfs_io_subrequest *netfs_create_write_request(struct netfs_io_request *
 		subreq->source	= dest;
 		subreq->start	= start;
 		subreq->len	= len;
-		subreq->debug_index = atomic_inc_return(&wreq->subreq_counter);
 
 		switch (subreq->source) {
 		case NETFS_UPLOAD_TO_SERVER: