From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754182AbaIVOrJ (ORCPT ); Mon, 22 Sep 2014 10:47:09 -0400 Received: from mga02.intel.com ([134.134.136.20]:20970 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753647AbaIVOrG (ORCPT ); Mon, 22 Sep 2014 10:47:06 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,571,1406617200"; d="scan'208";a="479187570" From: Octavian Purdila To: sameo@linux.intel.com, lee.jones@linaro.org Cc: linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, Octavian Purdila Subject: [PATCH] mfd: viperboard: allocate I/O buffer separately Date: Mon, 22 Sep 2014 17:46:52 +0300 Message-Id: <1411397212-31625-1-git-send-email-octavian.purdila@intel.com> X-Mailer: git-send-email 1.9.1 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 | 16 ++++++++++------ include/linux/mfd/viperboard.h | 2 +- 2 files changed, 11 insertions(+), 7 deletions(-) diff --git a/drivers/mfd/viperboard.c b/drivers/mfd/viperboard.c index e00f534..d27c131 100644 --- a/drivers/mfd/viperboard.c +++ b/drivers/mfd/viperboard.c @@ -59,9 +59,13 @@ static int vprbrd_probe(struct usb_interface *interface, /* allocate memory for our device state and initialize it */ vb = kzalloc(sizeof(*vb), GFP_KERNEL); - if (vb == NULL) { - dev_err(&interface->dev, "Out of memory\n"); + if (vb == NULL) 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); @@ -103,10 +107,9 @@ static int vprbrd_probe(struct usb_interface *interface, return 0; error: - if (vb) { - usb_put_dev(vb->usb_dev); - kfree(vb); - } + usb_put_dev(vb->usb_dev); + kfree(vb->buf); + kfree(vb); return ret; } @@ -118,6 +121,7 @@ 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