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authorCao jin <caoj.fnst@cn.fujitsu.com>2016-11-02 21:44:47 +0800
committerMichael Tokarev <mjt@tls.msk.ru>2017-01-24 23:26:53 +0300
commit6e4c890e15b23f078650499fbde11760b8eccf10 (patch)
tree0c606e5587a6c6a59b10d297e19ef9f5ca48f6a8 /util/mmap-alloc.c
parent4a3ecf201a1a49a804e8506df5906e446707c3b1 (diff)
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util/mmap-alloc: refactor a little bit for readability
1st mmap returns *ptr* which aligns to host page size, | size + align | ------------------------------------------ ptr input param *align* could be 1M, or 2M, or host page size. After QEMU_ALIGN_UP, offset will >= 0 2nd mmap use flag MAP_FIXED, then it return ptr+offset, or else fail. If it success, then we will have something like: | offset | size | -------------------------------------- ptr ptr1 *ptr1* is what we really want to return, it equals ptr+offset. Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Diffstat (limited to 'util/mmap-alloc.c')
-rw-r--r--util/mmap-alloc.c10
1 files changed, 4 insertions, 6 deletions
diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c
index d713a72..2f55f5e 100644
--- a/util/mmap-alloc.c
+++ b/util/mmap-alloc.c
@@ -84,22 +84,20 @@ 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)