Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760422AbcDEXky (ORCPT ); Tue, 5 Apr 2016 19:40:54 -0400 Received: from p3plsmtps2ded02.prod.phx3.secureserver.net ([208.109.80.59]:52011 "EHLO p3plsmtps2ded02.prod.phx3.secureserver.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760347AbcDEXkv (ORCPT ); Tue, 5 Apr 2016 19:40:51 -0400 x-originating-ip: 72.167.245.219 From: Jake Oshins To: linux-pci@vger.kernel.org, gregkh@linuxfoundation.org, kys@microsoft.com, linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com, vkuznets@redhat.com, haiyangz@microsoft.com, haddenh@microsoft.com, helgaas@kernel.org Cc: Jake Oshins Subject: [PATCH v5 1/6] drivers:hv: Lock access to hyperv_mmio resource tree Date: Tue, 5 Apr 2016 18:18:17 -0700 Message-Id: <1459905502-20798-2-git-send-email-jakeo@microsoft.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1459905502-20798-1-git-send-email-jakeo@microsoft.com> References: <1459905502-20798-1-git-send-email-jakeo@microsoft.com> X-CMAE-Envelope: MS4wfI9F+Sh/hpPIdDrVebDfPokFa3MTzeiDKzhWDfzQcqKIMfMDJbPB48ZQk4CX+YmNU/5qTWJVmYUkpHplFNHzanSFUVKZOUSq7Yo2BR+MndpTC78wguKT 9FiPOLuwaQTE0mo+gBy4E58kyyT+dbJLW/Qh709jK/xGmME3FfyIR8RolgbY51FuLeu6bKuI117WGpLUkdND1KXd/RUASYIQXrkD0JS1RCgU9WzbLj37eYpZ ELsEOy5E9X0U3zQC+JgWKU+XvUAyHYU4luX/GitjTiSowpLwW72ddn0RzTjdekrzINg/5759hpT6kv+i0jvEdNuUs/OYVhQZtpj+KXDcqRB+BaHCFZdjXVeB PZPaC4A2+3szBqEGfVZbWz0eCjJIl7bZAOxYFBH9toYfdJWDqeHMNsuEw68jzLXKEAmQh8SBFkmNJW8TehDFwDiCIAhM45p8bEXqf+p44LDxh+/4e9sjZ8rJ RpfBYNSkkxcVIzuyTywcohWWH+7csxrV/ZDmJ7dftaf++uuZNXBFSKUdtE7uGl/wnSFiswtQE05tEYTx Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1740 Lines: 59 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 --- drivers/hv/vmbus_drv.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 64713ff..799518b 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); -- 1.9.1