mm: kmemleak: remove kmemleak_not_leak_phys() and the min_count argument to kmemleak_alloc_phys()

Patch series "mm: kmemleak: store objects allocated with physical address
separately and check when scan", v4.

The kmemleak_*_phys() interface uses "min_low_pfn" and "max_low_pfn" to
check address.  But on some architectures, kmemleak_*_phys() is called
before those two variables initialized.  The following steps will be
taken:

1) Add OBJECT_PHYS flag and rbtree for the objects allocated
   with physical address
2) Store physical address in objects if allocated with OBJECT_PHYS
3) Check the boundary when scan instead of in kmemleak_*_phys()

This patch set will solve:
https://lore.kernel.org/r/20220527032504.30341-1-yee.lee@mediatek.com
https://lore.kernel.org/r/9dd08bb5-f39e-53d8-f88d-bec598a08c93@gmail.com

v3: https://lore.kernel.org/r/20220609124950.1694394-1-patrick.wang.shcn@gmail.com
v2: https://lore.kernel.org/r/20220603035415.1243913-1-patrick.wang.shcn@gmail.com
v1: https://lore.kernel.org/r/20220531150823.1004101-1-patrick.wang.shcn@gmail.com


This patch (of 4):

Remove the unused kmemleak_not_leak_phys() function.  And remove the
min_count argument to kmemleak_alloc_phys() function, assume it's 0.

Link: https://lkml.kernel.org/r/20220611035551.1823303-1-patrick.wang.shcn@gmail.com
Link: https://lkml.kernel.org/r/20220611035551.1823303-2-patrick.wang.shcn@gmail.com
Signed-off-by: Patrick Wang <patrick.wang.shcn@gmail.com>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Yee Lee <yee.lee@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Documentation/dev-tools/kmemleak.rst

@@ -174,7 +174,6 @@ mapping:
 
 - ``kmemleak_alloc_phys``
 - ``kmemleak_free_part_phys``
-- ``kmemleak_not_leak_phys``
 - ``kmemleak_ignore_phys``
 
 Dealing with false positives/negatives

drivers/of/fdt.c

@@ -529,7 +529,7 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,
 			pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
 				uname, &base, (unsigned long)(size / SZ_1M));
 			if (!nomap)
-				kmemleak_alloc_phys(base, size, 0, 0);
+				kmemleak_alloc_phys(base, size, 0);
 		}
 		else
 			pr_info("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",

include/linux/kmemleak.h

@@ -29,10 +29,9 @@ extern void kmemleak_not_leak(const void *ptr) __ref;
 extern void kmemleak_ignore(const void *ptr) __ref;
 extern void kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp) __ref;
 extern void kmemleak_no_scan(const void *ptr) __ref;
-extern void kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count,
+extern void kmemleak_alloc_phys(phys_addr_t phys, size_t size,
 				gfp_t gfp) __ref;
 extern void kmemleak_free_part_phys(phys_addr_t phys, size_t size) __ref;
-extern void kmemleak_not_leak_phys(phys_addr_t phys) __ref;
 extern void kmemleak_ignore_phys(phys_addr_t phys) __ref;
 
 static inline void kmemleak_alloc_recursive(const void *ptr, size_t size,
@@ -107,15 +106,12 @@ static inline void kmemleak_no_scan(const void *ptr)
 {
 }
 static inline void kmemleak_alloc_phys(phys_addr_t phys, size_t size,
-				       int min_count, gfp_t gfp)
+				       gfp_t gfp)
 {
 }
 static inline void kmemleak_free_part_phys(phys_addr_t phys, size_t size)
 {
 }
-static inline void kmemleak_not_leak_phys(phys_addr_t phys)
-{
-}
 static inline void kmemleak_ignore_phys(phys_addr_t phys)
 {
 }

mm/kmemleak.c

@@ -1125,15 +1125,13 @@ EXPORT_SYMBOL(kmemleak_no_scan);
  *			 address argument
  * @phys:	physical address of the object
  * @size:	size of the object
- * @min_count:	minimum number of references to this object.
- *              See kmemleak_alloc()
  * @gfp:	kmalloc() flags used for kmemleak internal memory allocations
  */
-void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, int min_count,
-			       gfp_t gfp)
+void __ref kmemleak_alloc_phys(phys_addr_t phys, size_t size, gfp_t gfp)
 {
 	if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
-		kmemleak_alloc(__va(phys), size, min_count, gfp);
+		/* assume min_count 0 */
+		kmemleak_alloc(__va(phys), size, 0, gfp);
 }
 EXPORT_SYMBOL(kmemleak_alloc_phys);
 
@@ -1151,18 +1149,6 @@ void __ref kmemleak_free_part_phys(phys_addr_t phys, size_t size)
 }
 EXPORT_SYMBOL(kmemleak_free_part_phys);
 
-/**
- * kmemleak_not_leak_phys - similar to kmemleak_not_leak but taking a physical
- *			    address argument
- * @phys:	physical address of the object
- */
-void __ref kmemleak_not_leak_phys(phys_addr_t phys)
-{
-	if (PHYS_PFN(phys) >= min_low_pfn && PHYS_PFN(phys) < max_low_pfn)
-		kmemleak_not_leak(__va(phys));
-}
-EXPORT_SYMBOL(kmemleak_not_leak_phys);
-
 /**
  * kmemleak_ignore_phys - similar to kmemleak_ignore but taking a physical
  *			  address argument

mm/memblock.c

@@ -1345,8 +1345,8 @@ __next_mem_pfn_range_in_zone(u64 *idx, struct zone *zone,
  * from the regions with mirroring enabled and then retried from any
  * memory region.
  *
- * In addition, function sets the min_count to 0 using kmemleak_alloc_phys for
- * allocated boot memory block, so that it is never reported as leaks.
+ * In addition, function using kmemleak_alloc_phys for allocated boot
+ * memory block, it is never reported as leaks.
  *
  * Return:
  * Physical address of allocated memory block on success, %0 on failure.
@@ -1398,12 +1398,12 @@ done:
 	 */
 	if (end != MEMBLOCK_ALLOC_NOLEAKTRACE)
 		/*
-		 * The min_count is set to 0 so that memblock allocated
-		 * blocks are never reported as leaks. This is because many
-		 * of these blocks are only referred via the physical
-		 * address which is not looked up by kmemleak.
+		 * Memblock allocated blocks are never reported as
+		 * leaks. This is because many of these blocks are
+		 * only referred via the physical address which is
+		 * not looked up by kmemleak.
 		 */
-		kmemleak_alloc_phys(found, size, 0, 0);
+		kmemleak_alloc_phys(found, size, 0);
 
 	return found;
 }

tools/testing/memblock/linux/kmemleak.h

@@ -7,7 +7,7 @@ static inline void kmemleak_free_part_phys(phys_addr_t phys, size_t size)
 }
 
 static inline void kmemleak_alloc_phys(phys_addr_t phys, size_t size,
-				       int min_count, gfp_t gfp)
+				       gfp_t gfp)
 {
 }