From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752614AbdIIXAL (ORCPT ); Sat, 9 Sep 2017 19:00:11 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:43076 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752442AbdIIXAH (ORCPT ); Sat, 9 Sep 2017 19:00:07 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Till Harbaum" , "Sebastian Reichel" , "Greg Kroah-Hartman" , "Wolfram Sang" Date: Sat, 09 Sep 2017 22:47:14 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 077/233] i2c: i2c-tiny-usb: fix buffer not being DMA capable In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.48-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Sebastian Reichel commit 5165da5923d6c7df6f2927b0113b2e4d9288661e upstream. Since v4.9 i2c-tiny-usb generates the below call trace and longer works, since it can't communicate with the USB device. The reason is, that since v4.9 the USB stack checks, that the buffer it should transfer is DMA capable. This was a requirement since v2.2 days, but it usually worked nevertheless. [ 17.504959] ------------[ cut here ]------------ [ 17.505488] WARNING: CPU: 0 PID: 93 at drivers/usb/core/hcd.c:1587 usb_hcd_map_urb_for_dma+0x37c/0x570 [ 17.506545] transfer buffer not dma capable [ 17.507022] Modules linked in: [ 17.507370] CPU: 0 PID: 93 Comm: i2cdetect Not tainted 4.11.0-rc8+ #10 [ 17.508103] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 17.509039] Call Trace: [ 17.509320] ? dump_stack+0x5c/0x78 [ 17.509714] ? __warn+0xbe/0xe0 [ 17.510073] ? warn_slowpath_fmt+0x5a/0x80 [ 17.510532] ? nommu_map_sg+0xb0/0xb0 [ 17.510949] ? usb_hcd_map_urb_for_dma+0x37c/0x570 [ 17.511482] ? usb_hcd_submit_urb+0x336/0xab0 [ 17.511976] ? wait_for_completion_timeout+0x12f/0x1a0 [ 17.512549] ? wait_for_completion_timeout+0x65/0x1a0 [ 17.513125] ? usb_start_wait_urb+0x65/0x160 [ 17.513604] ? usb_control_msg+0xdc/0x130 [ 17.514061] ? usb_xfer+0xa4/0x2a0 [ 17.514445] ? __i2c_transfer+0x108/0x3c0 [ 17.514899] ? i2c_transfer+0x57/0xb0 [ 17.515310] ? i2c_smbus_xfer_emulated+0x12f/0x590 [ 17.515851] ? _raw_spin_unlock_irqrestore+0x11/0x20 [ 17.516408] ? i2c_smbus_xfer+0x125/0x330 [ 17.516876] ? i2c_smbus_xfer+0x125/0x330 [ 17.517329] ? i2cdev_ioctl_smbus+0x1c1/0x2b0 [ 17.517824] ? i2cdev_ioctl+0x75/0x1c0 [ 17.518248] ? do_vfs_ioctl+0x9f/0x600 [ 17.518671] ? vfs_write+0x144/0x190 [ 17.519078] ? SyS_ioctl+0x74/0x80 [ 17.519463] ? entry_SYSCALL_64_fastpath+0x1e/0xad [ 17.519959] ---[ end trace d047c04982f5ac50 ]--- Signed-off-by: Sebastian Reichel Reviewed-by: Greg Kroah-Hartman Acked-by: Till Harbaum Signed-off-by: Wolfram Sang Signed-off-by: Ben Hutchings --- drivers/i2c/busses/i2c-tiny-usb.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) --- a/drivers/i2c/busses/i2c-tiny-usb.c +++ b/drivers/i2c/busses/i2c-tiny-usb.c @@ -178,22 +178,39 @@ static int usb_read(struct i2c_adapter * int value, int index, void *data, int len) { struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data; + void *dmadata = kmalloc(len, GFP_KERNEL); + int ret; + + if (!dmadata) + return -ENOMEM; /* do control transfer */ - return usb_control_msg(dev->usb_dev, usb_rcvctrlpipe(dev->usb_dev, 0), + ret = usb_control_msg(dev->usb_dev, usb_rcvctrlpipe(dev->usb_dev, 0), cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE | - USB_DIR_IN, value, index, data, len, 2000); + USB_DIR_IN, value, index, dmadata, len, 2000); + + memcpy(data, dmadata, len); + kfree(dmadata); + return ret; } static int usb_write(struct i2c_adapter *adapter, int cmd, int value, int index, void *data, int len) { struct i2c_tiny_usb *dev = (struct i2c_tiny_usb *)adapter->algo_data; + void *dmadata = kmemdup(data, len, GFP_KERNEL); + int ret; + + if (!dmadata) + return -ENOMEM; /* do control transfer */ - return usb_control_msg(dev->usb_dev, usb_sndctrlpipe(dev->usb_dev, 0), + ret = usb_control_msg(dev->usb_dev, usb_sndctrlpipe(dev->usb_dev, 0), cmd, USB_TYPE_VENDOR | USB_RECIP_INTERFACE, - value, index, data, len, 2000); + value, index, dmadata, len, 2000); + + kfree(dmadata); + return ret; } static void i2c_tiny_usb_free(struct i2c_tiny_usb *dev)