From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751963AbcI1Hwo (ORCPT ); Wed, 28 Sep 2016 03:52:44 -0400 Received: from relay1.mentorg.com ([192.94.38.131]:51366 "EHLO relay1.mentorg.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751543AbcI1HwS (ORCPT ); Wed, 28 Sep 2016 03:52:18 -0400 From: Mark Craske To: Greg Kroah-Hartman CC: , "George G. Davis" , Jiada Wang Subject: [PATCH v2 2/2] drivers: dma-coherent: Move spinlock in dma_alloc_from_coherent() Date: Wed, 28 Sep 2016 08:51:57 +0100 Message-ID: <1475049117-12201-3-git-send-email-Mark_Craske@mentor.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1475049117-12201-1-git-send-email-Mark_Craske@mentor.com> References: <1475049117-12201-1-git-send-email-Mark_Craske@mentor.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Bastian Hecht We don't need to hold the spinlock while zeroing the allocated memory. In case we handle big buffers this is a severe issue as other CPUs might be spinning half a second or longer. Signed-off-by: Bastian Hecht Signed-off-by: George G. Davis Signed-off-by: Mark Craske --- drivers/base/dma-coherent.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/base/dma-coherent.c b/drivers/base/dma-coherent.c index 2789f7a..640a7e6 100644 --- a/drivers/base/dma-coherent.c +++ b/drivers/base/dma-coherent.c @@ -165,6 +165,7 @@ int dma_alloc_from_coherent(struct device *dev, ssize_t size, int order = get_order(size); unsigned long flags; int pageno; + int dma_memory_map; if (!dev) return 0; @@ -187,11 +188,12 @@ int dma_alloc_from_coherent(struct device *dev, ssize_t size, */ *dma_handle = mem->device_base + (pageno << PAGE_SHIFT); *ret = mem->virt_base + (pageno << PAGE_SHIFT); - if (mem->flags & DMA_MEMORY_MAP) + dma_memory_map = (mem->flags & DMA_MEMORY_MAP); + spin_unlock_irqrestore(&mem->spinlock, flags); + if (dma_memory_map) memset(*ret, 0, size); else memset_io(*ret, 0, size); - spin_unlock_irqrestore(&mem->spinlock, flags); return 1; -- 1.7.9.5