Merge tag 'v3.13-rc4' into next

Linux 3.13-rc4

* tag 'v3.13-rc4': (1001 commits)
  Linux 3.13-rc4
  null_blk: mem garbage on NUMA systems during init
  radeon_pm: fix oops in hwmon_attributes_visible() and radeon_hwmon_show_temp_thresh()
  Revert "selinux: consider filesystem subtype in policies"
  igb: Fix for issue where values could be too high for udelay function.
  i40e: fix null dereference
  ARM: fix asm/memory.h build error
  dm array: fix a reference counting bug in shadow_ablock
  dm space map: disallow decrementing a reference count below zero
  mm: memcg: do not allow task about to OOM kill to bypass the limit
  mm: memcg: fix race condition between memcg teardown and swapin
  thp: move preallocated PTE page table on move_huge_pmd()
  mfd/rtc: s5m: fix register updating by adding regmap for RTC
  rtc: s5m: enable IRQ wake during suspend
  rtc: s5m: limit endless loop waiting for register update
  rtc: s5m: fix unsuccesful IRQ request during probe
  drivers/rtc/rtc-s5m.c: fix info->rtc assignment
  include/linux/kernel.h: make might_fault() a nop for !MMU
  drivers/rtc/rtc-at91rm9200.c: correct alarm over day/month wrap
  procfs: also fix proc_reg_get_unmapped_area() for !MMU case
  ...

Signed-off-by: Felipe Balbi <balbi@ti.com>

1 files changed, 52 insertions, 2 deletions

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 1e2f3f495843..53c2e296467f 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -2973,8 +2973,58 @@ static int prepare_ring(struct xhci_hcd *xhci, struct xhci_ring *ep_ring,
 	}
 
 	while (1) {
-		if (room_on_ring(xhci, ep_ring, num_trbs))
-			break;
+		if (room_on_ring(xhci, ep_ring, num_trbs)) {
+			union xhci_trb *trb = ep_ring->enqueue;
+			unsigned int usable = ep_ring->enq_seg->trbs +
+					TRBS_PER_SEGMENT - 1 - trb;
+			u32 nop_cmd;
+
+			/*
+			 * Section 4.11.7.1 TD Fragments states that a link
+			 * TRB must only occur at the boundary between
+			 * data bursts (eg 512 bytes for 480M).
+			 * While it is possible to split a large fragment
+			 * we don't know the size yet.
+			 * Simplest solution is to fill the trb before the
+			 * LINK with nop commands.
+			 */
+			if (num_trbs == 1 || num_trbs <= usable || usable == 0)
+				break;
+
+			if (ep_ring->type != TYPE_BULK)
+				/*
+				 * While isoc transfers might have a buffer that
+				 * crosses a 64k boundary it is unlikely.
+				 * Since we can't add NOPs without generating
+				 * gaps in the traffic just hope it never
+				 * happens at the end of the ring.
+				 * This could be fixed by writing a LINK TRB
+				 * instead of the first NOP - however the
+				 * TRB_TYPE_LINK_LE32() calls would all need
+				 * changing to check the ring length.
+				 */
+				break;
+
+			if (num_trbs >= TRBS_PER_SEGMENT) {
+				xhci_err(xhci, "Too many fragments %d, max %d\n",
+						num_trbs, TRBS_PER_SEGMENT - 1);
+				return -ENOMEM;
+			}
+
+			nop_cmd = cpu_to_le32(TRB_TYPE(TRB_TR_NOOP) |
+					ep_ring->cycle_state);
+			ep_ring->num_trbs_free -= usable;
+			do {
+				trb->generic.field[0] = 0;
+				trb->generic.field[1] = 0;
+				trb->generic.field[2] = 0;
+				trb->generic.field[3] = nop_cmd;
+				trb++;
+			} while (--usable);
+			ep_ring->enqueue = trb;
+			if (room_on_ring(xhci, ep_ring, num_trbs))
+				break;
+		}
 
 		if (ep_ring == xhci->cmd_ring) {
 			xhci_err(xhci, "Do not support expand command ring\n");