From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:45728 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932931AbcILRM7 (ORCPT ); Mon, 12 Sep 2016 13:12:59 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jake Oshins , "K. Y. Srinivasan" , Sasha Levin Subject: [PATCH 4.4 142/192] [PATCH 4.4 13/16] drivers:hv: Lock access to hyperv_mmio resource tree Date: Mon, 12 Sep 2016 19:00:51 +0200 Message-Id: <20160912152205.014647006@linuxfoundation.org> In-Reply-To: <20160912152158.855601725@linuxfoundation.org> References: <20160912152158.855601725@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jake Oshins [ Upstream commit e16dad6bfe1437aaee565f875a6713ca7ce81bdf ] 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 Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/hv/vmbus_drv.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -105,6 +105,7 @@ static struct notifier_block hyperv_pani }; struct resource *hyperv_mmio; +DEFINE_SEMAPHORE(hyperv_mmio_lock); static int vmbus_exists(void) { @@ -1140,7 +1141,10 @@ int vmbus_allocate_mmio(struct resource 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)) @@ -1177,13 +1181,17 @@ int vmbus_allocate_mmio(struct resource 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);