usb: xhci: move all segment re-numbering to xhci_link_rings()

This is a preparation patch for switching from custom segment list
handling to using list.h functions.

Contain all segment re-numbering in xhci_link_rings() which links two
segments lists together, and performs all necessary adjustments for
them to fit together.

No need to send segment number to xhci_alloc_segments_for_ring()
as a parameter after this.
Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20240626124835.1023046-11-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci-mem.c

@@ -153,7 +153,7 @@ static void xhci_link_rings(struct xhci_hcd *xhci, struct xhci_ring *ring,
 		ring->last_seg = last;
 	}
 
-	for (seg = last; seg != ring->last_seg; seg = seg->next)
+	for (seg = ring->enq_seg; seg != ring->last_seg; seg = seg->next)
 		seg->next->num = seg->num + 1;
 }
 
@@ -324,12 +324,16 @@ EXPORT_SYMBOL_GPL(xhci_initialize_ring_info);
 
 /* 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 num,
-		unsigned int cycle_state, enum xhci_ring_type type,
-		unsigned int max_packet, gfp_t flags)
+					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)
 {
 	struct xhci_segment *prev;
+	unsigned int num = 0;
 	bool chain_links;
 
 	chain_links = xhci_link_chain_quirk(xhci, type);
@@ -388,9 +392,8 @@ struct xhci_ring *xhci_ring_alloc(struct xhci_hcd *xhci,
 	if (num_segs == 0)
 		return ring;
 
-	ret = xhci_alloc_segments_for_ring(xhci, &ring->first_seg,
-			&ring->last_seg, num_segs, 0, cycle_state, type,
-			max_packet, flags);
+	ret = xhci_alloc_segments_for_ring(xhci, &ring->first_seg, &ring->last_seg, num_segs,
+					   cycle_state, type, max_packet, flags);
 	if (ret)
 		goto fail;
 
@@ -428,10 +431,8 @@ int xhci_ring_expansion(struct xhci_hcd *xhci, struct xhci_ring *ring,
 	struct xhci_segment	*last;
 	int			ret;
 
-	ret = xhci_alloc_segments_for_ring(xhci, &first, &last,
-			num_new_segs, ring->enq_seg->num + 1,
-			ring->cycle_state, ring->type,
-			ring->bounce_buf_len, flags);
+	ret = xhci_alloc_segments_for_ring(xhci, &first, &last, num_new_segs, ring->cycle_state,
+					   ring->type, ring->bounce_buf_len, flags);
 	if (ret)
 		return -ENOMEM;