[PATCH v2 2/4] xhci: fix issue of cross page boundary in TRB prefetch

[Weitao Wang]

On some Zhaoxin platforms, xHCI will prefetch TRB for performance
improvement. However this TRB prefetch mechanism may cross page boundary,
which may access memory not allocated by xHCI driver. In order to fix
this issue, two pages was allocated for TRB and only the first
page will be used.

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Weitao Wang <WeitaoWang-oc@xxxxxxxxxxx>
---
 drivers/usb/host/xhci-mem.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index d0a9467aa5fc..d5517400d874 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -2369,8 +2369,12 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
 	 * and our use of dma addresses in the trb_address_map radix tree needs
 	 * TRB_SEGMENT_SIZE alignment, so we pick the greater alignment need.
 	 */
-	xhci->segment_pool = dma_pool_create("xHCI ring segments", dev,
-			TRB_SEGMENT_SIZE, TRB_SEGMENT_SIZE, xhci->page_size);
+	if (xhci->quirks & XHCI_ZHAOXIN_TRB_FETCH)
+		xhci->segment_pool = dma_pool_create("xHCI ring segments", dev,
+				TRB_SEGMENT_SIZE * 2, TRB_SEGMENT_SIZE * 2, xhci->page_size * 2);
+	else
+		xhci->segment_pool = dma_pool_create("xHCI ring segments", dev,
+				TRB_SEGMENT_SIZE, TRB_SEGMENT_SIZE, xhci->page_size);
 
 	/* See Table 46 and Note on Figure 55 */
 	xhci->device_pool = dma_pool_create("xHCI input/output contexts", dev,
-- 
2.32.0