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[Qemu-trivial] [PATCH] util/mmap-alloc: check parameter before using
From: |
Cao jin |
Subject: |
[Qemu-trivial] [PATCH] util/mmap-alloc: check parameter before using |
Date: |
Wed, 26 Oct 2016 15:18:54 +0800 |
Also refactor some code hunk for readability
Signed-off-by: Cao jin <address@hidden>
---
util/mmap-alloc.c | 20 +++++++++-----------
1 file changed, 9 insertions(+), 11 deletions(-)
diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
index 5a85aa3..92c123a 100644
--- a/util/mmap-alloc.c
+++ b/util/mmap-alloc.c
@@ -41,6 +41,11 @@ size_t qemu_fd_getpagesize(int fd)
void *qemu_ram_mmap(int fd, size_t size, size_t align, bool shared)
{
+ /* Make sure align is a power of 2 */
+ assert(!(align & (align - 1)));
+ /* Always align to host page size */
+ assert(align >= getpagesize());
+
/*
* Note: this always allocates at least one extra page of virtual address
* space, even if size is already aligned.
@@ -68,11 +73,6 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool
shared)
return MAP_FAILED;
}
- /* Make sure align is a power of 2 */
- assert(!(align & (align - 1)));
- /* Always align to host page size */
- assert(align >= getpagesize());
-
ptr1 = mmap(ptr + offset, size, PROT_READ | PROT_WRITE,
MAP_FIXED |
(fd == -1 ? MAP_ANONYMOUS : 0) |
@@ -83,22 +83,20 @@ void *qemu_ram_mmap(int fd, size_t size, size_t align, bool
shared)
return MAP_FAILED;
}
- ptr += offset;
- total -= offset;
-
if (offset > 0) {
- munmap(ptr - offset, offset);
+ munmap(ptr, offset);
}
/*
* Leave a single PROT_NONE page allocated after the RAM block, to serve as
* a guard page guarding against potential buffer overflows.
*/
+ total -= offset;
if (total > size + getpagesize()) {
- munmap(ptr + size + getpagesize(), total - size - getpagesize());
+ munmap(ptr1 + size + getpagesize(), total - size - getpagesize());
}
- return ptr;
+ return ptr1;
}
void qemu_ram_munmap(void *ptr, size_t size)
--
2.1.0
- [Qemu-trivial] [PATCH] util/mmap-alloc: check parameter before using,
Cao jin <=