4.16-stable review patch. If anyone has any objections, please let me know.
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From: Takashi Iwai tiwai@suse.de
commit 9e7f06c8beee304ee21b791653fefcd713f48b9a upstream.
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: stable@vger.kernel.org # v4.16+ Signed-off-by: Takashi Iwai tiwai@suse.de Signed-off-by: Christoph Hellwig hch@lst.de Cc: Jean Delvare jdelvare@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- lib/swiotlb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/lib/swiotlb.c +++ b/lib/swiotlb.c @@ -732,7 +732,7 @@ swiotlb_alloc_buffer(struct device *dev, goto out_warn;
*dma_handle = swiotlb_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);