[PATCH 3/5] mm: nobootmem: implement reserve_bootmem() in terms of memblock.

[Avery Pennarun <apenwarr@gmail.com>]

There was an implementation for it in mm/bootmem.c, but it was left out of
nobootmem.c, and we can easily write a memblock implementation.  That way
code (eg.  printk) that wants to reserve memory early on can just always
call bootmem on all platforms.

Signed-off-by: Avery Pennarun <apenwarr@gmail.com>
---
 mm/nobootmem.c |   23 +++++++++++++++++++++++
 1 files changed, 23 insertions(+), 0 deletions(-)

diff --git a/mm/nobootmem.c b/mm/nobootmem.c
index 24f0fc1..2c269da 100644
--- a/mm/nobootmem.c
+++ b/mm/nobootmem.c
@@ -193,6 +193,29 @@ void __init free_bootmem(unsigned long addr, unsigned long size)
 	memblock_free(addr, size);
 }
 
+/**
+ * reserve_bootmem - mark a page range as reserved
+ * @addr: starting address of the range
+ * @size: size of the range in bytes
+ * @flags: reservation flags (see linux/bootmem.h)
+ *
+ * Partial pages will be reserved.
+ *
+ * The range must be contiguous but may span node boundaries.
+ */
+int __init reserve_bootmem(unsigned long addr, unsigned long size,
+			    int flags)
+{
+	if (flags & BOOTMEM_EXCLUSIVE) {
+		phys_addr_t m = memblock_find_in_range(addr, addr + size,
+					size, PAGE_SIZE);
+		if (m != addr)
+			return -EBUSY;
+	}
+	memblock_reserve(addr, size);
+	return 0;
+}
+
 static void * __init ___alloc_bootmem_nopanic(unsigned long size,
 					unsigned long align,
 					unsigned long goal,
-- 
1.7.7.3

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