s390/boot: cleanup adjust_to_uv_max() function

Uncouple input and output arguments by making the latter
the function return value.
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

arch/s390/boot/startup.c

@@ -152,6 +152,7 @@ static void setup_kernel_memory_layout(void)
 	unsigned long vmemmap_start;
 	unsigned long rte_size;
 	unsigned long pages;
+	unsigned long vmax;
 
 	pages = ident_map_size / PAGE_SIZE;
 	/* vmemmap contains a multiple of PAGES_PER_SECTION struct pages */
@@ -163,10 +164,10 @@ static void setup_kernel_memory_layout(void)
 	    vmalloc_size > _REGION2_SIZE ||
 	    vmemmap_start + vmemmap_size + vmalloc_size + MODULES_LEN >
 		    _REGION2_SIZE) {
-		MODULES_END = _REGION1_SIZE;
+		vmax = _REGION1_SIZE;
 		rte_size = _REGION2_SIZE;
 	} else {
-		MODULES_END = _REGION2_SIZE;
+		vmax = _REGION2_SIZE;
 		rte_size = _REGION3_SIZE;
 	}
 	/*
@@ -174,11 +175,12 @@ static void setup_kernel_memory_layout(void)
 	 * secure storage limit, so that any vmalloc allocation
 	 * we do could be used to back secure guest storage.
 	 */
-	adjust_to_uv_max(&MODULES_END);
+	vmax = adjust_to_uv_max(vmax);
 #ifdef CONFIG_KASAN
 	/* force vmalloc and modules below kasan shadow */
-	MODULES_END = min(MODULES_END, KASAN_SHADOW_START);
+	vmax = min(vmax, KASAN_SHADOW_START);
 #endif
+	MODULES_END = vmax;
 	MODULES_VADDR = MODULES_END - MODULES_LEN;
 	VMALLOC_END = MODULES_VADDR;
 

arch/s390/boot/uv.c

@@ -51,10 +51,11 @@ void uv_query_info(void)
 }
 
 #if IS_ENABLED(CONFIG_KVM)
-void adjust_to_uv_max(unsigned long *vmax)
+unsigned long adjust_to_uv_max(unsigned long limit)
 {
 	if (is_prot_virt_host() && uv_info.max_sec_stor_addr)
-		*vmax = min_t(unsigned long, *vmax, uv_info.max_sec_stor_addr);
+		limit = min_t(unsigned long, limit, uv_info.max_sec_stor_addr);
+	return limit;
 }
 
 static int is_prot_virt_host_capable(void)

arch/s390/boot/uv.h

@@ -3,10 +3,13 @@
 #define BOOT_UV_H
 
 #if IS_ENABLED(CONFIG_KVM)
-void adjust_to_uv_max(unsigned long *vmax);
+unsigned long adjust_to_uv_max(unsigned long limit);
 void sanitize_prot_virt_host(void);
 #else
-static inline void adjust_to_uv_max(unsigned long *vmax) {}
+static inline unsigned long adjust_to_uv_max(unsigned long limit)
+{
+	return limit;
+}
 static inline void sanitize_prot_virt_host(void) {}
 #endif