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memblock: Make memblock functions handle overflowing range @size

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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>
This commit is contained in:
Tejun Heo
2011-12-08 10:22:07 -08:00
parent 719361809f
commit eb18f1b5bf
1 changed files with 12 additions and 3 deletions
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15
mm/memblock.c
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@@ -49,6 +49,12 @@ static inline const char *memblock_type_name(struct memblock_type *type)
return "unknown"; 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 * 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) phys_addr_t base, phys_addr_t size)
{ {
bool insert = false; 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; int i, nr_new;
/* special case for empty array */ /* 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, phys_addr_t base, phys_addr_t size,
int *start_rgn, int *end_rgn) int *start_rgn, int *end_rgn)
{ {
phys_addr_t end = base + size; phys_addr_t end = base + memblock_cap_size(base, &size);
int i; int i;
*start_rgn = *end_rgn = 0; *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 __init_memblock memblock_is_region_memory(phys_addr_t base, phys_addr_t size)
{ {
int idx = memblock_search(&memblock.memory, base); int idx = memblock_search(&memblock.memory, base);
phys_addr_t end = base + memblock_cap_size(base, &size);
if (idx == -1) if (idx == -1)
return 0; 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].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) 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; return memblock_overlaps_region(&memblock.reserved, base, size) >= 0;
} }