[PATCH 1/2] Drivers: hv: vmbus: Rework use of DMA_BIT_MASK(64)

[Tim Gardner]

From: Michael Kelley <mikelley at microsoft.com>

BugLink: https://bugs.launchpad.net/bugs/1975717

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 at kernel.org>
Reported-by: Vitaly Chikunov <vt at altlinux.org>
Reported-by: Jakub Kicinski <kuba at kernel.org>
Fixes: 743b237c3a7b ("scsi: storvsc: Add Isolation VM support for storvsc driver")
Signed-off-by: Michael Kelley <mikelley at microsoft.com>
Reviewed-by: Nathan Chancellor <nathan at kernel.org>
Tested-by: Nathan Chancellor <nathan at kernel.org>
Link: https://lore.kernel.org/r/1644176216-12531-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu at kernel.org>
(cherry picked from commit 6bf625a4140f24b490766043b307f8252519578b)
Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
---
 drivers/hv/vmbus_drv.c | 4 ++--
 include/linux/hyperv.h | 1 +
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 72d2911d1ed4..0ae5758b0076 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2100,7 +2100,6 @@ 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
  */
@@ -2141,8 +2140,9 @@ 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 8e18ecfae674..148b075be922 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1292,6 +1292,7 @@ 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;
-- 
2.36.1