kasan, x86, arm64, s390: rename functions for modules shadow

Rename kasan_free_shadow to kasan_free_module_shadow and
kasan_module_alloc to kasan_alloc_module_shadow.

These functions are used to allocate/free shadow memory for kernel modules
when KASAN_VMALLOC is not enabled.  The new names better reflect their
purpose.

Also reword the comment next to their declaration to improve clarity.

Link: https://lkml.kernel.org/r/36db32bde765d5d0b856f77d2d806e838513fe84.1643047180.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

arch/arm64/kernel/module.c

@@ -58,7 +58,7 @@ void *module_alloc(unsigned long size)
 				PAGE_KERNEL, 0, NUMA_NO_NODE,
 				__builtin_return_address(0));
 
-	if (p && (kasan_module_alloc(p, size, gfp_mask) < 0)) {
+	if (p && (kasan_alloc_module_shadow(p, size, gfp_mask) < 0)) {
 		vfree(p);
 		return NULL;
 	}

arch/s390/kernel/module.c

@@ -45,7 +45,7 @@ void *module_alloc(unsigned long size)
 	p = __vmalloc_node_range(size, MODULE_ALIGN, MODULES_VADDR, MODULES_END,
 				 gfp_mask, PAGE_KERNEL_EXEC, VM_DEFER_KMEMLEAK, NUMA_NO_NODE,
 				 __builtin_return_address(0));
-	if (p && (kasan_module_alloc(p, size, gfp_mask) < 0)) {
+	if (p && (kasan_alloc_module_shadow(p, size, gfp_mask) < 0)) {
 		vfree(p);
 		return NULL;
 	}

arch/x86/kernel/module.c

@@ -78,7 +78,7 @@ void *module_alloc(unsigned long size)
 				    MODULES_END, gfp_mask,
 				    PAGE_KERNEL, VM_DEFER_KMEMLEAK, NUMA_NO_NODE,
 				    __builtin_return_address(0));
-	if (p && (kasan_module_alloc(p, size, gfp_mask) < 0)) {
+	if (p && (kasan_alloc_module_shadow(p, size, gfp_mask) < 0)) {
 		vfree(p);
 		return NULL;
 	}

include/linux/kasan.h

@@ -454,17 +454,17 @@ static inline void kasan_populate_early_vm_area_shadow(void *start,
 		!defined(CONFIG_KASAN_VMALLOC)
 
 /*
- * These functions provide a special case to support backing module
- * allocations with real shadow memory. With KASAN vmalloc, the special
- * case is unnecessary, as the work is handled in the generic case.
+ * These functions allocate and free shadow memory for kernel modules.
+ * They are only required when KASAN_VMALLOC is not supported, as otherwise
+ * shadow memory is allocated by the generic vmalloc handlers.
  */
-int kasan_module_alloc(void *addr, size_t size, gfp_t gfp_mask);
-void kasan_free_shadow(const struct vm_struct *vm);
+int kasan_alloc_module_shadow(void *addr, size_t size, gfp_t gfp_mask);
+void kasan_free_module_shadow(const struct vm_struct *vm);
 
 #else /* (CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS) && !CONFIG_KASAN_VMALLOC */
 
-static inline int kasan_module_alloc(void *addr, size_t size, gfp_t gfp_mask) { return 0; }
-static inline void kasan_free_shadow(const struct vm_struct *vm) {}
+static inline int kasan_alloc_module_shadow(void *addr, size_t size, gfp_t gfp_mask) { return 0; }
+static inline void kasan_free_module_shadow(const struct vm_struct *vm) {}
 
 #endif /* (CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS) && !CONFIG_KASAN_VMALLOC */
 

mm/kasan/shadow.c

@@ -498,7 +498,7 @@ void kasan_release_vmalloc(unsigned long start, unsigned long end,
 
 #else /* CONFIG_KASAN_VMALLOC */
 
-int kasan_module_alloc(void *addr, size_t size, gfp_t gfp_mask)
+int kasan_alloc_module_shadow(void *addr, size_t size, gfp_t gfp_mask)
 {
 	void *ret;
 	size_t scaled_size;
@@ -534,7 +534,7 @@ int kasan_module_alloc(void *addr, size_t size, gfp_t gfp_mask)
 	return -ENOMEM;
 }
 
-void kasan_free_shadow(const struct vm_struct *vm)
+void kasan_free_module_shadow(const struct vm_struct *vm)
 {
 	if (vm->flags & VM_KASAN)
 		vfree(kasan_mem_to_shadow(vm->addr));

mm/vmalloc.c

@@ -2526,7 +2526,7 @@ struct vm_struct *remove_vm_area(const void *addr)
 		va->vm = NULL;
 		spin_unlock(&vmap_area_lock);
 
-		kasan_free_shadow(vm);
+		kasan_free_module_shadow(vm);
 		free_unmap_vmap_area(va);
 
 		return vm;