xhci: Adjust segment numbers after ring expansion

Initial xhci_ring allocation has just been amended to assign a
monotonically increasing number to each ring segment.

However rings may be expanded after initial allocation.

So number newly inserted segments starting from the preceding segment in
the ring and renumber all segments succeeding the newly inserted ones.

This is not a fix because ring expansion currently isn't done on the
Event Ring and that's the only ring type using the segment number.
It's just in preparation for when either Event Ring expansion is added
or when other ring types start making use of the segment number.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20231019102924.2797346-7-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci-mem.c

@@ -130,7 +130,7 @@ static void xhci_link_rings(struct xhci_hcd *xhci, struct xhci_ring *ring,
 		struct xhci_segment *first, struct xhci_segment *last,
 		unsigned int num_segs)
 {
-	struct xhci_segment *next;
+	struct xhci_segment *next, *seg;
 	bool chain_links;
 
 	if (!ring || !first || !last)
@@ -153,6 +153,9 @@ static void xhci_link_rings(struct xhci_hcd *xhci, struct xhci_ring *ring,
 			|= cpu_to_le32(LINK_TOGGLE);
 		ring->last_seg = last;
 	}
+
+	for (seg = last; seg != ring->last_seg; seg = seg->next)
+		seg->next->num = seg->num + 1;
 }
 
 /*
@@ -322,11 +325,11 @@ void xhci_initialize_ring_info(struct xhci_ring *ring,
 /* Allocate segments and link them for a ring */
 static int xhci_alloc_segments_for_ring(struct xhci_hcd *xhci,
 		struct xhci_segment **first, struct xhci_segment **last,
-		unsigned int num_segs, unsigned int cycle_state,
-		enum xhci_ring_type type, unsigned int max_packet, gfp_t flags)
+		unsigned int num_segs, unsigned int num,
+		unsigned int cycle_state, enum xhci_ring_type type,
+		unsigned int max_packet, gfp_t flags)
 {
 	struct xhci_segment *prev;
-	unsigned int num = 0;
 	bool chain_links;
 
 	/* Set chain bit for 0.95 hosts, and for isoc rings on AMD 0.96 host */
@@ -392,7 +395,7 @@ struct xhci_ring *xhci_ring_alloc(struct xhci_hcd *xhci,
 		return ring;
 
 	ret = xhci_alloc_segments_for_ring(xhci, &ring->first_seg,
-			&ring->last_seg, num_segs, cycle_state, type,
+			&ring->last_seg, num_segs, 0, cycle_state, type,
 			max_packet, flags);
 	if (ret)
 		goto fail;
@@ -432,7 +435,8 @@ int xhci_ring_expansion(struct xhci_hcd *xhci, struct xhci_ring *ring,
 	int			ret;
 
 	ret = xhci_alloc_segments_for_ring(xhci, &first, &last,
-			num_new_segs, ring->cycle_state, ring->type,
+			num_new_segs, ring->enq_seg->num + 1,
+			ring->cycle_state, ring->type,
 			ring->bounce_buf_len, flags);
 	if (ret)
 		return -ENOMEM;