Drivers: hv: vmbus: Rework use of DMA_BIT_MASK(64)

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 <vt@altlinux.org>
Reported-by: Jakub Kicinski <kuba@kernel.org>
Fixes: 743b237c3a7b ("scsi: storvsc: Add Isolation VM support for storvsc driver")
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/1644176216-12531-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 34a4fd2..12a2b37 100644 (file)
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2082,7 +2082,6 @@ struct hv_device *vmbus_device_create(const guid_t *type,
        return child_device_obj;
 }
 
-static u64 vmbus_dma_mask = DMA_BIT_MASK(64);
 /*
  * vmbus_device_register - Register the child device
  */
@@ -2123,8 +2122,9 @@ int vmbus_device_register(struct hv_device *child_device_obj)
        }
        hv_debug_add_dev_dir(child_device_obj);
 
-       child_device_obj->device.dma_mask = &vmbus_dma_mask;
        child_device_obj->device.dma_parms = &child_device_obj->dma_parms;
+       child_device_obj->device.dma_mask = &child_device_obj->dma_mask;
+       dma_set_mask(&child_device_obj->device, DMA_BIT_MASK(64));
        return 0;
 
 err_kset_unregister:

diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index f565a89..fe2e017 100644 (file)
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1262,6 +1262,7 @@ struct hv_device {
        struct vmbus_channel *channel;
        struct kset          *channels_kset;
        struct device_dma_parameters dma_parms;
+       u64 dma_mask;
 
        /* place holder to keep track of the dir for hv device in debugfs */
        struct dentry *debug_dir;