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@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
diff --git a/mm/memblock.c b/mm/memblock.c
index fffe68b..945dc312 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -49,6 +49,12 @@
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 @@
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 @@
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_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;
}