Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753520AbbDGJrZ (ORCPT ); Tue, 7 Apr 2015 05:47:25 -0400 Received: from mail-lb0-f170.google.com ([209.85.217.170]:35610 "EHLO mail-lb0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753475AbbDGJrS (ORCPT ); Tue, 7 Apr 2015 05:47:18 -0400 From: Johan Hovold To: Greg Kroah-Hartman , Felipe Balbi , Alan Stern Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Stephen Warren , Thierry Reding , Alexandre Courbot , linux-tegra@vger.kernel.org, Johan Hovold , stable Subject: [PATCH 1/2] USB: musb: fix inefficient copy of unaligned buffers Date: Tue, 7 Apr 2015 11:46:51 +0200 Message-Id: <1428400012-7563-2-git-send-email-johan@kernel.org> X-Mailer: git-send-email 2.0.5 In-Reply-To: <1428400012-7563-1-git-send-email-johan@kernel.org> References: <1428400012-7563-1-git-send-email-johan@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1547 Lines: 40 Make sure only to copy any actual data rather than the whole buffer, when releasing the temporary buffer used for unaligned transfer buffers. Note that this also fixes a lockup on disconnect, where repeated failed transfers would starve the hub workqueue from processing the disconnect, which would have prevented the urbs from being resubmitted. In this case there is no data to forward, but the full buffer length was being copied nonetheless. The disconnect lockup can easily be reproduced using four unaligned 4k-bulk-in urbs on Beaglebone Black. Fixes: 8408fd1d83e3 ("usb: musb: implement (un)map_urb_for_dma hooks") Cc: stable # v3.10 Signed-off-by: Johan Hovold --- drivers/usb/musb/musb_host.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c index c3d5fc9dfb5b..d8327ec19a1f 100644 --- a/drivers/usb/musb/musb_host.c +++ b/drivers/usb/musb/musb_host.c @@ -2523,7 +2523,7 @@ static void musb_free_temp_buffer(struct urb *urb) if (dir == DMA_FROM_DEVICE) { memcpy(temp->old_xfer_buffer, temp->data, - urb->transfer_buffer_length); + urb->actual_length); } urb->transfer_buffer = temp->old_xfer_buffer; kfree(temp->kmalloc_ptr); -- 2.0.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/