On Mon, Feb 07, 2022 at 02:42:31AM +0000, Michael Kelley (LINUX) wrote:

From: Nathan Chancellor <nathan@kernel.org> Sent: Sunday, February 6, 2022 5:38 PM

quoted

Hi Michael,

On Sun, Feb 06, 2022 at 11:36:56AM -0800, Michael Kelley wrote:

quoted

Using DMA_BIT_MASK(64) as an initializer for a global variable
causes problems with Clang 12.0.1. The compiler doesn't understand
that value 64 is excluded from the shift at compile time, resulting
in a build error.

While this is a compiler problem, avoid the issue by setting up
the dma_mask memory as part of struct hv_device, and initialize
it using dma_set_mask().

Reported-by: Nathan Chancellor <nathan@kernel.org>
Reported-by: Vitaly Chikunov <redacted>
Reported-by: Jakub Kicinski <kuba@kernel.org>
Fixes: 743b237c3a7b ("scsi: storvsc: Add Isolation VM support for storvsc driver")
Signed-off-by: Michael Kelley <redacted>

Thanks a lot for working around this. I am hoping that this will be
fixed in clang soon, as it is high priority on our list of issues to
fix. Once it has been fixed, we should be able to undo this workaround
in one way or another.

FWIW, the new code is as good a solution as the old code.  The new code
also follows some existing patterns, such as with struct platform_device.
As such, I don't think of this as a workaround that needs to be undone
in the future.

Yes indeed.

Patch applied to hyperv-fixes. Thanks.