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[Qemu-devel] [PATCH, v3] shmat(): use mmap_find_vma to find free memory
From: |
Kirill A. Shutemov |
Subject: |
[Qemu-devel] [PATCH, v3] shmat(): use mmap_find_vma to find free memory area |
Date: |
Mon, 10 Nov 2008 09:09:41 +0200 |
Signed-off-by: Kirill A. Shutemov <address@hidden>
---
linux-user/syscall.c | 32 ++++++++++++++++++++++++--------
1 files changed, 24 insertions(+), 8 deletions(-)
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 7142606..ebf7375 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -2271,25 +2271,40 @@ static inline abi_long do_shmctl(int shmid, int cmd,
abi_long buf)
static inline abi_long do_shmat(int shmid, abi_ulong shmaddr, int shmflg,
unsigned long *raddr)
{
+ abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size);
abi_long ret;
struct shmid_ds shm_info;
int i;
- /* SHM_* flags are the same on all linux platforms */
- *raddr = (unsigned long) shmat(shmid, g2h(shmaddr), shmflg);
-
- if (*raddr == -1) {
- return get_errno(*raddr);
- }
-
/* find out the length of the shared memory segment */
ret = get_errno(shmctl(shmid, IPC_STAT, &shm_info));
if (is_error(ret)) {
/* can't get length, bail out */
- shmdt((void *) *raddr);
return get_errno(ret);
}
+ mmap_lock();
+
+ if (shmaddr)
+ *raddr = (unsigned long) shmat(shmid, g2h(shmaddr), shmflg);
+ else {
+ abi_ulong mmap_start;
+
+ mmap_start = mmap_find_vma(0, shm_info.shm_segsz);
+
+ if (mmap_start == -1) {
+ errno = ENOMEM;
+ *raddr = -1;
+ } else
+ *raddr = (unsigned long) shmat(shmid, g2h(mmap_start),
+ shmflg | SHM_REMAP);
+ }
+
+ if (*raddr == -1) {
+ mmap_unlock();
+ return get_errno(*raddr);
+ }
+
page_set_flags(h2g(*raddr), h2g(*raddr) + shm_info.shm_segsz,
PAGE_VALID | PAGE_READ |
((shmflg & SHM_RDONLY)? 0 : PAGE_WRITE));
@@ -2302,6 +2317,7 @@ static inline abi_long do_shmat(int shmid, abi_ulong
shmaddr, int shmflg,
}
}
+ mmap_unlock();
return 0;
}
--
1.6.0.2.GIT
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