From: Vitaly Chikunov <vt@xxxxxxxxxxxx> Sent: Thursday, February 3, 2022 4:58 PM > > GCC 11.2.1 cannot understand that value 64 is excluded from the shift > at compile time resulting in build error[1]: > > 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. If we need a temporary hack to solve the build problem, I can live with that. But I see 230 other places in kernel code where DMA_BIT_MASK(64) is used, so I'm wondering if this particular hack is effective. We need a more comprehensive solution that fixes the definition of DMA_BIT_MASK() so it will work with a constant '64' as the parameter. Michael > > Cc: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx> > Cc: Michael Kelley <mikelley@xxxxxxxxxxxxx> > Cc: Long Li <longli@xxxxxxxxxxxxx> > Cc: Wei Liu <wei.liu@xxxxxxxxxx> > Link: https://lore.kernel.org/linux-hyperv/20220203235828.hcsj6najsl7yxmxa@xxxxxxxxxxxx/ > Signed-off-by: Vitaly Chikunov <vt@xxxxxxxxxxxx> > --- > drivers/hv/vmbus_drv.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c > index 17bf55fe3169..2376ee484362 100644 > --- a/drivers/hv/vmbus_drv.c > +++ b/drivers/hv/vmbus_drv.c > @@ -2079,7 +2079,7 @@ struct hv_device *vmbus_device_create(const guid_t *type, > return child_device_obj; > } > > -static u64 vmbus_dma_mask = DMA_BIT_MASK(64); > +static u64 vmbus_dma_mask = ~0ULL; > /* > * vmbus_device_register - Register the child device > */ > -- > 2.33.0
