Commit-ID: eb18f1b5bfb99b1d7d2f5d792e6ee5c9b7d89330
Gitweb: http://git.kernel.org/tip/eb18f1b5bfb99b1d7d2f5d792e6ee5c9b7d89330
Author: Tejun Heo <tj@xxxxxxxxxx>
AuthorDate: Thu, 8 Dec 2011 10:22:07 -0800
Committer: Tejun Heo <tj@xxxxxxxxxx>
CommitDate: Thu, 8 Dec 2011 10:22:07 -0800
memblock: Make memblock functions handle overflowing range @size
Allow memblock users to specify range where @base + @size overflows
and automatically cap it at maximum. This makes the interface more
robust and specifying till-the-end-of-memory easier.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
---
mm/memblock.c | 15 ++++++++++++---
1 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/mm/memblock.c b/mm/memblock.c
index fffe68b..945dc31 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -49,6 +49,12 @@ static inline const char *memblock_type_name(struct memblock_type *type)
return "unknown";
}
+/* adjust *@size so that (@base + *@size) doesn't overflow, return new size */
+static inline phys_addr_t memblock_cap_size(phys_addr_t base, phys_addr_t *size)
+{
+ return *size = min(*size, (phys_addr_t)ULLONG_MAX - base);
+}
+
/*
* Address comparison utilities
*/
@@ -328,7 +334,8 @@ static int __init_memblock memblock_add_region(struct memblock_type *type,
phys_addr_t base, phys_addr_t size)
{
bool insert = false;
- phys_addr_t obase = base, end = base + size;
+ phys_addr_t obase = base;
+ phys_addr_t end = base + memblock_cap_size(base, &size);
int i, nr_new;
/* special case for empty array */
@@ -420,7 +427,7 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type,
phys_addr_t base, phys_addr_t size,
int *start_rgn, int *end_rgn)
{
- phys_addr_t end = base + size;
+ phys_addr_t end = base + memblock_cap_size(base, &size);
int i;
*start_rgn = *end_rgn = 0;
@@ -868,16 +875,18 @@ int __init_memblock memblock_is_memory(phys_addr_t addr)
int __init_memblock memblock_is_region_memory(phys_addr_t base, phys_addr_t size)
{
int idx = memblock_search(&memblock.memory, base);
+ phys_addr_t end = base + memblock_cap_size(base, &size);
if (idx == -1)
return 0;
return memblock.memory.regions[idx].base <= base &&
(memblock.memory.regions[idx].base +
- memblock.memory.regions[idx].size) >= (base + size);
+ memblock.memory.regions[idx].size) >= end;
}
int __init_memblock memblock_is_region_reserved(phys_addr_t base, phys_addr_t size)
{
+ memblock_cap_size(base, &size);
return memblock_overlaps_region(&memblock.reserved, base, size) >= 0;
}
--
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