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-rw-r--r--mm/cma.c49
1 files changed, 33 insertions, 16 deletions
diff --git a/mm/cma.c b/mm/cma.c
index 62a5dccc3fb8..c30a6edee65c 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -253,23 +253,24 @@ int __init cma_declare_contiguous(phys_addr_t base,
return -EINVAL;
/*
- * adjust limit to avoid crossing low/high memory boundary for
- * automatically allocated regions
+ * If allocating at a fixed base the request region must not cross the
+ * low/high memory boundary.
*/
- if (((limit == 0 || limit > memblock_end) &&
- (memblock_end - size < highmem_start &&
- memblock_end > highmem_start)) ||
- (!fixed && limit > highmem_start && limit - size < highmem_start)) {
- limit = highmem_start;
- }
-
- if (fixed && base < highmem_start && base+size > highmem_start) {
+ if (fixed && base < highmem_start && base + size > highmem_start) {
ret = -EINVAL;
pr_err("Region at %08lx defined on low/high memory boundary (%08lx)\n",
(unsigned long)base, (unsigned long)highmem_start);
goto err;
}
+ /*
+ * If the limit is unspecified or above the memblock end, its effective
+ * value will be the memblock end. Set it explicitly to simplify further
+ * checks.
+ */
+ if (limit == 0 || limit > memblock_end)
+ limit = memblock_end;
+
/* Reserve memory */
if (fixed) {
if (memblock_is_region_reserved(base, size) ||
@@ -278,14 +279,30 @@ int __init cma_declare_contiguous(phys_addr_t base,
goto err;
}
} else {
- phys_addr_t addr = memblock_alloc_range(size, alignment, base,
- limit);
+ phys_addr_t addr = 0;
+
+ /*
+ * All pages in the reserved area must come from the same zone.
+ * If the requested region crosses the low/high memory boundary,
+ * try allocating from high memory first and fall back to low
+ * memory in case of failure.
+ */
+ if (base < highmem_start && limit > highmem_start) {
+ addr = memblock_alloc_range(size, alignment,
+ highmem_start, limit);
+ limit = highmem_start;
+ }
+
if (!addr) {
- ret = -ENOMEM;
- goto err;
- } else {
- base = addr;
+ addr = memblock_alloc_range(size, alignment, base,
+ limit);
+ if (!addr) {
+ ret = -ENOMEM;
+ goto err;
+ }
}
+
+ base = addr;
}
ret = cma_init_reserved_mem(base, size, order_per_bit, res_cma);