From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753368AbcDBQdd (ORCPT ); Sat, 2 Apr 2016 12:33:33 -0400 Received: from p3plsmtps2ded04.prod.phx3.secureserver.net ([208.109.80.198]:41631 "EHLO p3plsmtps2ded04.prod.phx3.secureserver.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753087AbcDBQda (ORCPT ); Sat, 2 Apr 2016 12:33:30 -0400 x-originating-ip: 72.167.245.219 From: "K. Y. Srinivasan" To: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com, vkuznets@redhat.com, jasowang@redhat.com Cc: Jake Oshins , "K. Y. Srinivasan" Subject: [PATCH 3/6] hv: Lock access to hyperv_mmio resource tree Date: Sat, 2 Apr 2016 11:10:58 -0700 Message-Id: <1459620661-16720-3-git-send-email-kys@microsoft.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1459620661-16720-1-git-send-email-kys@microsoft.com> References: <1459620638-16681-1-git-send-email-kys@microsoft.com> <1459620661-16720-1-git-send-email-kys@microsoft.com> X-CMAE-Envelope: MS4wfJ1S9nit96J/WsWOW5EKPQWmDECL0c5z2GSwl+Hgcy7kIFou2t5z98rQzEJH0/Gq/3yzJkYBgGZ3XIMeoM+LwvWRggN88BHjF92eQq8BzkFErI7ne+LU awQojafrIWX1JzWU0t3Vv3uNoCCEkyiZ7hyc6Zsy2IqOI422M/kbFZQl8nvRh5Gv9PVWPH4pklsMuw6vmePHugojcZEFnzaV6Wa0e5yp5z7X1xeZMcelnwx3 cfe0m7+fDn+wMcX7Qhf82CkAPS5YQvT+7y1ScQiOBoCFRLl+AS5sflcvpFRBeb5HYnGV0pOhAr6vUfJXYvuDI5VB52BQuvrJTijXVxlZ/BYw6OCE2mlB2APo KNP0HgfFyCbMp5mB4+uiivbv16S/eHwOJEmHIwal35+5jrqZ0RH117HHTynHQCSW9zgTgMtyErOdSBJu2I7iwI8NhPwXdA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jake Oshins In existing code, this tree of resources is created in single-threaded code and never modified after it is created, and thus needs no locking. This patch introduces a semaphore for tree access, as other patches in this series introduce run-time modifications of this resource tree which can happen on multiple threads. Signed-off-by: Jake Oshins Signed-off-by: K. Y. Srinivasan --- drivers/hv/vmbus_drv.c | 16 ++++++++++++---- 1 files changed, 12 insertions(+), 4 deletions(-) diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 44e95a4..60553c1 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -102,6 +102,7 @@ static struct notifier_block hyperv_panic_block = { }; struct resource *hyperv_mmio; +DEFINE_SEMAPHORE(hyperv_mmio_lock); static int vmbus_exists(void) { @@ -1132,7 +1133,10 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj, resource_size_t range_min, range_max, start, local_min, local_max; const char *dev_n = dev_name(&device_obj->device); u32 fb_end = screen_info.lfb_base + (screen_info.lfb_size << 1); - int i; + int i, retval; + + retval = -ENXIO; + down(&hyperv_mmio_lock); for (iter = hyperv_mmio; iter; iter = iter->sibling) { if ((iter->start >= max) || (iter->end <= min)) @@ -1169,13 +1173,17 @@ int vmbus_allocate_mmio(struct resource **new, struct hv_device *device_obj, for (; start + size - 1 <= local_max; start += align) { *new = request_mem_region_exclusive(start, size, dev_n); - if (*new) - return 0; + if (*new) { + retval = 0; + goto exit; + } } } } - return -ENXIO; +exit: + up(&hyperv_mmio_lock); + return retval; } EXPORT_SYMBOL_GPL(vmbus_allocate_mmio); -- 1.7.4.1