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swiotlb: fix unexpected swiotlb_alloc_coherent failures 

The code refactoring by commit 0176adb004 ("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: 0176adb004 ("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>
This commit is contained in:
Takashi Iwai 2018-04-10 19:05:13 +02:00 committed by Christoph Hellwig
parent b284d4d5a6
commit 9e7f06c8be
1 changed files with 1 additions and 1 deletions
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2
lib/swiotlb.c
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@ -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);