[PATCH 0/2] mm/memblock.c: fix potential bug and code refine

[PATCH 0/2] mm/memblock.c: fix potential bug and code refine

[Wei Yang]

Here are two patch of mm/memblock.c.
[1]. A trivial code refine in memblock_is_region_memory(), which removes an
unnecessary check on base address.
[2]. The original code forgets to check the return value of
memblock_reserve(), which may lead to potential problem. The patch fix this.

Wei Yang (2):
  mm/memblock.c: trivial code refine in memblock_is_region_memory()
  mm/memblock.c: check return value of memblock_reserve() in
    memblock_virt_alloc_internal()

 include/linux/memblock.h |    5 ++---
 mm/memblock.c            |    8 +++-----
 2 files changed, 5 insertions(+), 8 deletions(-)

-- 
1.7.9.5

[PATCH 1/2] mm/memblock.c: trivial code refine in memblock_is_region_memory()

[Wei Yang]

The base address is already guaranteed to be in the region by
memblock_search().

This patch removes the check on base, also a little refine in a macro.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
---
 include/linux/memblock.h |    5 ++---
 mm/memblock.c            |    2 +-
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 3106ac1..e611819 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -408,9 +408,8 @@ static inline unsigned long memblock_region_reserved_end_pfn(const struct memblo
 	     region++)
 
 #define for_each_memblock_type(memblock_type, rgn)			\
-	idx = 0;							\
-	rgn = &memblock_type->regions[idx];				\
-	for (idx = 0; idx < memblock_type->cnt;				\
+	for (idx = 0, rgn = &memblock_type->regions[idx];		\
+	     idx < memblock_type->cnt;					\
 	     idx++,rgn = &memblock_type->regions[idx])
 
 #ifdef CONFIG_MEMTEST
diff --git a/mm/memblock.c b/mm/memblock.c
index ac12489..9d402d05 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1557,7 +1557,7 @@ int __init_memblock memblock_is_region_memory(phys_addr_t base, phys_addr_t size
 
 	if (idx == -1)
 		return 0;
-	return memblock.memory.regions[idx].base <= base &&
+	return /* memblock.memory.regions[idx].base <= base && */
 		(memblock.memory.regions[idx].base +
 		 memblock.memory.regions[idx].size) >= end;
 }
-- 
1.7.9.5

[PATCH 2/2] mm/memblock.c: check return value of memblock_reserve() in memblock_virt_alloc_internal()

[Wei Yang]

memblock_reserve() may fail in case there is not enough regions.

This patch checks the return value.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
---
 mm/memblock.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/mm/memblock.c b/mm/memblock.c
index 9d402d05..83ad703 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1268,18 +1268,17 @@ static void * __init memblock_virt_alloc_internal(
 
 	if (max_addr > memblock.current_limit)
 		max_addr = memblock.current_limit;
-
 again:
 	alloc = memblock_find_in_range_node(size, align, min_addr, max_addr,
 					    nid, flags);
-	if (alloc)
+	if (alloc && !memblock_reserve(alloc, size))
 		goto done;
 
 	if (nid != NUMA_NO_NODE) {
 		alloc = memblock_find_in_range_node(size, align, min_addr,
 						    max_addr, NUMA_NO_NODE,
 						    flags);
-		if (alloc)
+		if (alloc && !memblock_reserve(alloc, size))
 			goto done;
 	}
 
@@ -1297,7 +1296,6 @@ again:
 
 	return NULL;
 done:
-	memblock_reserve(alloc, size);
 	ptr = phys_to_virt(alloc);
 	memset(ptr, 0, size);
 
-- 
1.7.9.5