From eb18f1b5bfb99b1d7d2f5d792e6ee5c9b7d89330 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 8 Dec 2011 10:22:07 -0800 Subject: [PATCH] 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 Cc: Benjamin Herrenschmidt Cc: Yinghai Lu --- mm/memblock.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/mm/memblock.c b/mm/memblock.c index fffe68b4bf14..945dc31258eb 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; }