From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753589AbaIYPlv (ORCPT ); Thu, 25 Sep 2014 11:41:51 -0400 Received: from mga11.intel.com ([192.55.52.93]:38793 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752759AbaIYPlt (ORCPT ); Thu, 25 Sep 2014 11:41:49 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,597,1406617200"; d="scan'208";a="605317597" From: Octavian Purdila To: sameo@linux.intel.com, lee.jones@linaro.org Cc: linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, johan@kernel.org, Octavian Purdila Subject: [PATCH v4 1/3] mfd: viperboard: allocate I/O buffer separately Date: Thu, 25 Sep 2014 18:41:35 +0300 Message-Id: <1411659697-27258-2-git-send-email-octavian.purdila@intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1411659697-27258-1-git-send-email-octavian.purdila@intel.com> References: <1411659697-27258-1-git-send-email-octavian.purdila@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently the I/O buffer is allocated part of the device status structure, potentially sharing the same cache line with other members in this structure. Allocate the buffer separately, to avoid the I/O operations corrupting the device status structure due to cache line sharing. Compiled tested only as I don't have access to hardware. Signed-off-by: Octavian Purdila --- drivers/mfd/viperboard.c | 8 ++++++++ include/linux/mfd/viperboard.h | 2 +- 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/mfd/viperboard.c b/drivers/mfd/viperboard.c index e00f534..5f62f4e 100644 --- a/drivers/mfd/viperboard.c +++ b/drivers/mfd/viperboard.c @@ -64,6 +64,12 @@ static int vprbrd_probe(struct usb_interface *interface, return -ENOMEM; } + vb->buf = kzalloc(sizeof(struct vprbrd_i2c_write_msg), GFP_KERNEL); + if (vb->buf == NULL) { + ret = -ENOMEM; + goto error; + } + mutex_init(&vb->lock); vb->usb_dev = usb_get_dev(interface_to_usbdev(interface)); @@ -105,6 +111,7 @@ static int vprbrd_probe(struct usb_interface *interface, error: if (vb) { usb_put_dev(vb->usb_dev); + kfree(vb->buf); kfree(vb); } @@ -118,6 +125,7 @@ static void vprbrd_disconnect(struct usb_interface *interface) mfd_remove_devices(&interface->dev); usb_set_intfdata(interface, NULL); usb_put_dev(vb->usb_dev); + kfree(vb->buf); kfree(vb); dev_dbg(&interface->dev, "disconnected\n"); diff --git a/include/linux/mfd/viperboard.h b/include/linux/mfd/viperboard.h index 1934528..af928d0 100644 --- a/include/linux/mfd/viperboard.h +++ b/include/linux/mfd/viperboard.h @@ -103,7 +103,7 @@ struct vprbrd_i2c_addr_msg { struct vprbrd { struct usb_device *usb_dev; /* the usb device for this device */ struct mutex lock; - u8 buf[sizeof(struct vprbrd_i2c_write_msg)]; + u8 *buf; struct platform_device pdev; }; -- 1.9.1