From patchwork Wed Feb 24 21:23:59 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jake Oshins X-Patchwork-Id: 587748 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 570981402BC for ; Thu, 25 Feb 2016 08:26:23 +1100 (AEDT) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=sendgrid.me header.i=@sendgrid.me header.b=MenEWd71; dkim-atps=neutral Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758619AbcBXVZ7 (ORCPT ); Wed, 24 Feb 2016 16:25:59 -0500 Received: from o1.f.az.sendgrid.net ([208.117.55.132]:12657 "EHLO o1.f.az.sendgrid.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758605AbcBXVZ5 (ORCPT ); Wed, 24 Feb 2016 16:25:57 -0500 DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sendgrid.me; h=from:to:cc:subject:in-reply-to:references; s=smtpapi; bh=xI29AHB5Fl7el5xOfqYL/t5YB+Q=; b=MenEWd71vx0NMajwB6noQ/NQjwd+G EkM9VnZVN2I2Ic27Wx5T24szEb81/s6V9/hIFBisUWO+9BJNiOHFIgJ831RJmwNe aTxjlEL6/mrKLgdBlIxbgql2m3tZNTzUqaTMncCgz3sffqvG2Ssymbit7RWXqkzT mb1t2U9erRIvNE= Received: by filter0108p1las1.sendgrid.net with SMTP id filter0108p1las1.16799.56CE1FDE2F 2016-02-24 21:25:50.883343486 +0000 UTC Received: from jakeoshinsu2.jakeoshinsu2.d1.internal.cloudapp.net (unknown [104.210.40.47]) by ismtpd0012p1las1.sendgrid.net (SG) with ESMTP id zsa6FdGMTeiR1CRkg32oyA Wed, 24 Feb 2016 21:25:50.786 +0000 (UTC) From: jakeo@microsoft.com 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 Cc: Jake Oshins Subject: [PATCH 2/5] hv: Lock access to hyperv_mmio resource tree Date: Wed, 24 Feb 2016 21:23:59 +0000 Message-Id: <1456349042-16275-3-git-send-email-jakeo@microsoft.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1456349042-16275-1-git-send-email-jakeo@microsoft.com> References: <1456349042-16275-1-git-send-email-jakeo@microsoft.com> X-SG-EID: lfnueJVzSjg1mfuVqqukVH7tZvRy9mfCIcBnfbfzaMMKF+DcLOnuwUNvSKtXbTLQsfOyjKsAQIlwIF R66bypMi5qNDTZsJpkwVwy0M4YEMeJ4jYolV8PoualMDcvFUVZm6E66XNM3lxHP5IcaAY1AWSFxiR1 zy2O6O/mc1anhWxnYw3I2MpqR756zq1yNowg1Vrc0ymv9uuBHiclWW7xpQ== Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@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 --- 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 69393ff..1da18e1 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -103,6 +103,7 @@ static struct notifier_block hyperv_panic_block = { }; struct resource *hyperv_mmio; +DEFINE_SEMAPHORE(hyperv_mmio_lock); static int vmbus_exists(void) { @@ -1173,7 +1174,10 @@ 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)) @@ -1210,13 +1214,17 @@ 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);