FAILED: patch "[PATCH] xhci: Fix immediate data transfer if buffer is already DMA" failed to apply to 5.2-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.2-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 13b82b746310b51b064bc855993a1c84bf862726 Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman@linux.intel.com>
Date: Wed, 22 May 2019 14:34:00 +0300
Subject: [PATCH] xhci: Fix immediate data transfer if buffer is already DMA
 mapped

xhci immediate data transfer (IDT) support in 5.2-rc1 caused regression
on various Samsung Exynos boards with ASIX USB 2.0 ethernet dongle.

If the transfer buffer in the URB is already DMA mapped then IDT should
not be used. urb->transfer_dma will already contain a valid dma address,
and there is no guarantee the data in urb->transfer_buffer is valid.

The IDT support patch used urb->transfer_dma as a temporary storage,
copying data from urb->transfer_buffer into it.

Issue was solved by preventing IDT if transfer buffer is already dma
mapped, and by not using urb->transfer_dma as temporary storage.

Fixes: 33e39350ebd2 ("usb: xhci: add Immediate Data Transfer support")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
CC: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index ef7c8698772e..88392aa65722 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -3432,11 +3432,14 @@ int xhci_queue_ctrl_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 
 	if (urb->transfer_buffer_length > 0) {
 		u32 length_field, remainder;
+		u64 addr;
 
 		if (xhci_urb_suitable_for_idt(urb)) {
-			memcpy(&urb->transfer_dma, urb->transfer_buffer,
+			memcpy(&addr, urb->transfer_buffer,
 			       urb->transfer_buffer_length);
 			field |= TRB_IDT;
+		} else {
+			addr = (u64) urb->transfer_dma;
 		}
 
 		remainder = xhci_td_remainder(xhci, 0,
@@ -3449,8 +3452,8 @@ int xhci_queue_ctrl_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 		if (setup->bRequestType & USB_DIR_IN)
 			field |= TRB_DIR_IN;
 		queue_trb(xhci, ep_ring, true,
-				lower_32_bits(urb->transfer_dma),
-				upper_32_bits(urb->transfer_dma),
+				lower_32_bits(addr),
+				upper_32_bits(addr),
 				length_field,
 				field | ep_ring->cycle_state);
 	}
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index a450a99e90eb..7f8b950d1a73 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -2160,7 +2160,8 @@ static inline bool xhci_urb_suitable_for_idt(struct urb *urb)
 {
 	if (!usb_endpoint_xfer_isoc(&urb->ep->desc) && usb_urb_dir_out(urb) &&
 	    usb_endpoint_maxp(&urb->ep->desc) >= TRB_IDT_MAX_SIZE &&
-	    urb->transfer_buffer_length <= TRB_IDT_MAX_SIZE)
+	    urb->transfer_buffer_length <= TRB_IDT_MAX_SIZE &&
+	    !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP))
 		return true;
 
 	return false;