[PATCH v3] drivers: hv: vmbus: Fix build on Clang 12 failed by DMA_BIT_MASK(64) expansion

[Vitaly Chikunov <vt@altlinux.org>]

Clang 12.0.1 cannot understand that value 64 is excluded from the shift
at compile time (for use in global context) resulting in build error:

  drivers/hv/vmbus_drv.c:2082:29: error: shift count >= width of type [-Werror,-Wshift-count-overflow]
  static u64 vmbus_dma_mask = DMA_BIT_MASK(64);
			      ^~~~~~~~~~~~~~~~
  ./include/linux/dma-mapping.h:76:54: note: expanded from macro 'DMA_BIT_MASK'
  #define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
						       ^ ~~~

Avoid using DMA_BIT_MASK macro for that corner case.

Cc: Tianyu Lan <Tianyu.Lan@microsoft.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Long Li <longli@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
---
 drivers/hv/vmbus_drv.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 17bf55fe3169..a1306ca15d3f 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2079,7 +2079,8 @@ struct hv_device *vmbus_device_create(const guid_t *type,
 	return child_device_obj;
 }
 
-static u64 vmbus_dma_mask = DMA_BIT_MASK(64);
+/* Use ~0ULL instead of DMA_BIT_MASK(64) to work around a bug in Clang. */
+static u64 vmbus_dma_mask = ~0ULL;
 /*
  * vmbus_device_register - Register the child device
  */
-- 
2.33.0