From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751947AbeDJRFS (ORCPT ); Tue, 10 Apr 2018 13:05:18 -0400 Received: from mx2.suse.de ([195.135.220.15]:40605 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751775AbeDJRFR (ORCPT ); Tue, 10 Apr 2018 13:05:17 -0400 From: Takashi Iwai To: Christoph Hellwig Cc: =?UTF-8?q?Christian=20K=C3=B6nig?= , Konrad Rzeszutek Wilk , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: [PATCH] swiotlb: Fix unexpected swiotlb_alloc_coherent() failures Date: Tue, 10 Apr 2018 19:05:13 +0200 Message-Id: <20180410170513.22834-1-tiwai@suse.de> X-Mailer: git-send-email 2.16.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The code refactoring by commit 0176adb00406 ("swiotlb: refactor coherent buffer allocation") made swiotlb_alloc_buffer() almost always failing due to a thinko: namely, the function evaluates the dma_coherent_ok() call incorrectly and dealing as if it's invalid. This ends up with weird errors like iwlwifi probe failure or amdgpu screen flickering. This patch corrects the logic error. Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=1088658 Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=1088902 Fixes: 0176adb00406 ("swiotlb: refactor coherent buffer allocation") Cc: # v4.16+ Signed-off-by: Takashi Iwai --- lib/swiotlb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/swiotlb.c b/lib/swiotlb.c index 47aeb04c1997..de7cc540450f 100644 --- a/lib/swiotlb.c +++ b/lib/swiotlb.c @@ -719,7 +719,7 @@ swiotlb_alloc_buffer(struct device *dev, size_t size, dma_addr_t *dma_handle, goto out_warn; *dma_handle = __phys_to_dma(dev, phys_addr); - if (dma_coherent_ok(dev, *dma_handle, size)) + if (!dma_coherent_ok(dev, *dma_handle, size)) goto out_unmap; memset(phys_to_virt(phys_addr), 0, size); -- 2.16.3