x86/hyper-v: Fix definition of HV_MAX_FLUSH_REP_COUNT

The max flush rep count of HvFlushGuestPhysicalAddressList hypercall is
equal with how many entries of union hv_gpa_page_range can be populated
into the input parameter page.

The code lacks parenthesis around PAGE_SIZE - 2 * sizeof(u64) which results
in bogus computations. Add them.

Fixes: cc4edae4b924 ("x86/hyper-v: Add HvFlushGuestAddressList hypercall support")
Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: kys@microsoft.com
Cc: haiyangz@microsoft.com
Cc: sthemmin@microsoft.com
Cc: sashal@kernel.org
Cc: bp@alien8.de
Cc: hpa@zytor.com
Cc: gregkh@linuxfoundation.org
Cc: devel@linuxdriverproject.org
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20190225143114.5149-1-Tianyu.Lan@microsoft.com

diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
index 705dafc2d11ab5bb9ddf3b249e0a69dae31a966e..2bdbbbcfa393fd6b2df936029917d20dc4ae8e84 100644 (file)
--- a/arch/x86/include/asm/hyperv-tlfs.h
+++ b/arch/x86/include/asm/hyperv-tlfs.h
@@ -841,7 +841,7 @@ union hv_gpa_page_range {
  * count is equal with how many entries of union hv_gpa_page_range can
  * be populated into the input parameter page.
  */
-#define HV_MAX_FLUSH_REP_COUNT (PAGE_SIZE - 2 * sizeof(u64) /  \
+#define HV_MAX_FLUSH_REP_COUNT ((PAGE_SIZE - 2 * sizeof(u64)) /        \
                                sizeof(union hv_gpa_page_range))
 
 struct hv_guest_mapping_flush_list {