xhci: Fix immediate data transfer if buffer is already DMA mapped (13b82b74) · Commits · 戴 / test

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: ("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>

drivers/usb/host/xhci-ring.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -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);
		}

drivers/usb/host/xhci.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -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;

Admin message