mm/memblock: introduce PHYS_ADDR_MAX

So far code was using ULLONG_MAX and type casting to obtain a
phys_addr_t with all bits set.  The typecast is necessary to silence
compiler warnings on 32-bit platforms.

Use the simpler but still type safe approach "~(phys_addr_t)0" to create a
preprocessor define for all bits set.

Link: http://lkml.kernel.org/r/20180406213809.566-1-stefan@agner.ch
Signed-off-by: Stefan Agner <stefan@agner.ch>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 7aed926245311e228cc653a6a8bb926b1add961d..7c4e8f1f72d8ab7f974f9d9aa2c6c2426ff937ea 100644 (file)
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -29,6 +29,7 @@
 #define LLONG_MIN      (-LLONG_MAX - 1)
 #define ULLONG_MAX     (~0ULL)
 #define SIZE_MAX       (~(size_t)0)
+#define PHYS_ADDR_MAX  (~(phys_addr_t)0)
 
 #define U8_MAX         ((u8)~0U)
 #define S8_MAX         ((s8)(U8_MAX>>1))

diff --git a/mm/memblock.c b/mm/memblock.c
index 5108356ad8aaddc9d24d9a0edf716553d75507b5..eec988c21c7e473da97c7e66e09244158ff3577d 100644 (file)
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -68,7 +68,7 @@ ulong __init_memblock choose_memblock_flags(void)
 /* 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);
+       return *size = min(*size, PHYS_ADDR_MAX - base);
 }
 
 /*
@@ -925,7 +925,7 @@ void __init_memblock __next_mem_range(u64 *idx, int nid, ulong flags,
                        r = &type_b->regions[idx_b];
                        r_start = idx_b ? r[-1].base + r[-1].size : 0;
                        r_end = idx_b < type_b->cnt ?
-                               r->base : (phys_addr_t)ULLONG_MAX;
+                               r->base : PHYS_ADDR_MAX;
 
                        /*
                         * if idx_b advanced past idx_a,
@@ -1041,7 +1041,7 @@ void __init_memblock __next_mem_range_rev(u64 *idx, int nid, ulong flags,
                        r = &type_b->regions[idx_b];
                        r_start = idx_b ? r[-1].base + r[-1].size : 0;
                        r_end = idx_b < type_b->cnt ?
-                               r->base : (phys_addr_t)ULLONG_MAX;
+                               r->base : PHYS_ADDR_MAX;
                        /*
                         * if idx_b advanced past idx_a,
                         * break out to advance idx_a
@@ -1516,13 +1516,13 @@ phys_addr_t __init_memblock memblock_end_of_DRAM(void)
 
 static phys_addr_t __init_memblock __find_max_addr(phys_addr_t limit)
 {
-       phys_addr_t max_addr = (phys_addr_t)ULLONG_MAX;
+       phys_addr_t max_addr = PHYS_ADDR_MAX;
        struct memblock_region *r;
 
        /*
         * translate the memory @limit size into the max address within one of
         * the memory memblock regions, if the @limit exceeds the total size
-        * of those regions, max_addr will keep original value ULLONG_MAX
+        * of those regions, max_addr will keep original value PHYS_ADDR_MAX
         */
        for_each_memblock(memory, r) {
                if (limit <= r->size) {
@@ -1537,7 +1537,7 @@ static phys_addr_t __init_memblock __find_max_addr(phys_addr_t limit)
 
 void __init memblock_enforce_memory_limit(phys_addr_t limit)
 {
-       phys_addr_t max_addr = (phys_addr_t)ULLONG_MAX;
+       phys_addr_t max_addr = PHYS_ADDR_MAX;
 
        if (!limit)
                return;
@@ -1545,14 +1545,14 @@ void __init memblock_enforce_memory_limit(phys_addr_t limit)
        max_addr = __find_max_addr(limit);
 
        /* @limit exceeds the total size of the memory, do nothing */
-       if (max_addr == (phys_addr_t)ULLONG_MAX)
+       if (max_addr == PHYS_ADDR_MAX)
                return;
 
        /* truncate both memory and reserved regions */
        memblock_remove_range(&memblock.memory, max_addr,
-                             (phys_addr_t)ULLONG_MAX);
+                             PHYS_ADDR_MAX);
        memblock_remove_range(&memblock.reserved, max_addr,
-                             (phys_addr_t)ULLONG_MAX);
+                             PHYS_ADDR_MAX);
 }
 
 void __init memblock_cap_memory_range(phys_addr_t base, phys_addr_t size)
@@ -1580,7 +1580,7 @@ void __init memblock_cap_memory_range(phys_addr_t base, phys_addr_t size)
        /* truncate the reserved regions */
        memblock_remove_range(&memblock.reserved, 0, base);
        memblock_remove_range(&memblock.reserved,
-                       base + size, (phys_addr_t)ULLONG_MAX);
+                       base + size, PHYS_ADDR_MAX);
 }
 
 void __init memblock_mem_limit_remove_map(phys_addr_t limit)
@@ -1593,7 +1593,7 @@ void __init memblock_mem_limit_remove_map(phys_addr_t limit)
        max_addr = __find_max_addr(limit);
 
        /* @limit exceeds the total size of the memory, do nothing */
-       if (max_addr == (phys_addr_t)ULLONG_MAX)
+       if (max_addr == PHYS_ADDR_MAX)
                return;
 
        memblock_cap_memory_range(0, max_addr);