linux-kernel - [PATCH 1/1] mshv: Fix compiler warning about cast converting incompatible function type

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Message-Id: <20260118170245.160050-1-mhklinux@outlook.com>
Date: Sun, 18 Jan 2026 09:02:45 -0800
From: mhkelley58@...il.com
To: kys@...rosoft.com,
	haiyangz@...rosoft.com,
	wei.liu@...nel.org,
	decui@...rosoft.com,
	longli@...rosoft.com,
	linux-hyperv@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Subject: [PATCH 1/1] mshv: Fix compiler warning about cast converting incompatible function type

From: Michael Kelley <mhklinux@...look.com>

In mshv_vtl_sint_ioctl_pause_msg_stream(), the reference to function
mshv_vtl_synic_mask_vmbus_sint() is cast to type smp_call_func_t. The
cast generates a compiler warning because the function signature of
mshv_vtl_synic_mask_vmbus_sint() doesn't match smp_call_func_t.

There's no actual bug here because the mis-matched function signatures
are compatible at runtime. Nonetheless, eliminate the compiler warning
by changing the function signature of mshv_vtl_synic_mask_vmbus_sint()
to match what on_each_cpu() expects. Remove the cast because it is then
no longer necessary.

No functional change.

Reported-by: kernel test robot <lkp@...el.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202601170352.qbh3EKH5-lkp@intel.com/
Signed-off-by: Michael Kelley <mhklinux@...look.com>
---
 drivers/hv/mshv_vtl_main.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/hv/mshv_vtl_main.c b/drivers/hv/mshv_vtl_main.c
index 2cebe9de5a5a..7bbbce009732 100644
--- a/drivers/hv/mshv_vtl_main.c
+++ b/drivers/hv/mshv_vtl_main.c
@@ -845,9 +845,10 @@ static const struct file_operations mshv_vtl_fops = {
 	.mmap = mshv_vtl_mmap,
 };
 
-static void mshv_vtl_synic_mask_vmbus_sint(const u8 *mask)
+static void mshv_vtl_synic_mask_vmbus_sint(void *info)
 {
 	union hv_synic_sint sint;
+	const u8 *mask = info;
 
 	sint.as_uint64 = 0;
 	sint.vector = HYPERVISOR_CALLBACK_VECTOR;
@@ -999,7 +1000,7 @@ static int mshv_vtl_sint_ioctl_pause_msg_stream(struct mshv_sint_mask __user *ar
 	if (copy_from_user(&mask, arg, sizeof(mask)))
 		return -EFAULT;
 	guard(mutex)(&vtl2_vmbus_sint_mask_mutex);
-	on_each_cpu((smp_call_func_t)mshv_vtl_synic_mask_vmbus_sint, &mask.mask, 1);
+	on_each_cpu(mshv_vtl_synic_mask_vmbus_sint, &mask.mask, 1);
 	WRITE_ONCE(vtl_synic_mask_vmbus_sint_masked, mask.mask != 0);
 	if (mask.mask)
 		wake_up_interruptible_poll(&fd_wait_queue, EPOLLIN);
-- 
2.25.1