Linux: -Wlogical-not-parentheses in drivers/iommu/dma-iommu.c

[nathanchance]

drivers/iommu/dma-iommu.c:897:6: warning: logical not is only applied to the left hand side of this comparison [-Wlogical-not-parentheses]
        if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
            ^                                 ~~
drivers/iommu/dma-iommu.c:897:6: note: add parentheses after the '!' to evaluate the comparison first
        if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
            ^
             (                                    )
drivers/iommu/dma-iommu.c:897:6: note: add parentheses around left hand side expression to silence this warning
        if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
            ^
            (                                )
1 warning generated.

Patch sent: https://lore.kernel.org/lkml/[email protected]/

[nathanchance]

Fixed: https://git.kernel.org/next/linux-next/c/1b961423158caaae49d3900b7c9c37477bbfa9b3

[nickdesaulniers]

This is a good case for why this warning isn't just a stylistic warning as this case turned out to be a bug.