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Subject[PATCH 11/14] ipc: teach the mm about range locking
Date
Conversion is straightforward, mmap_sem is used within the
the same function context most of the time. No change in
semantics.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
---
ipc/shm.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/ipc/shm.c b/ipc/shm.c
index ce1ca9f7c6e9..3666fa71bfc2 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -1418,6 +1418,7 @@ COMPAT_SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, void __user *, uptr)
long do_shmat(int shmid, char __user *shmaddr, int shmflg,
ulong *raddr, unsigned long shmlba)
{
+ DEFINE_RANGE_LOCK_FULL(mmrange);
struct shmid_kernel *shp;
unsigned long addr = (unsigned long)shmaddr;
unsigned long size;
@@ -1544,7 +1545,7 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg,
if (err)
goto out_fput;

- if (down_write_killable(&current->mm->mmap_sem)) {
+ if (mm_write_lock_killable(current->mm, &mmrange)) {
err = -EINTR;
goto out_fput;
}
@@ -1564,7 +1565,7 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg,
if (IS_ERR_VALUE(addr))
err = (long)addr;
invalid:
- up_write(&current->mm->mmap_sem);
+ mm_write_unlock(current->mm, &mmrange);
if (populate)
mm_populate(addr, populate);

@@ -1625,6 +1626,7 @@ COMPAT_SYSCALL_DEFINE3(shmat, int, shmid, compat_uptr_t, shmaddr, int, shmflg)
*/
long ksys_shmdt(char __user *shmaddr)
{
+ DEFINE_RANGE_LOCK_FULL(mmrange);
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
unsigned long addr = (unsigned long)shmaddr;
@@ -1638,7 +1640,7 @@ long ksys_shmdt(char __user *shmaddr)
if (addr & ~PAGE_MASK)
return retval;

- if (down_write_killable(&mm->mmap_sem))
+ if (mm_write_lock_killable(mm, &mmrange))
return -EINTR;

/*
@@ -1726,7 +1728,7 @@ long ksys_shmdt(char __user *shmaddr)

#endif

- up_write(&mm->mmap_sem);
+ mm_write_unlock(mm, &mmrange);
return retval;
}

--
2.16.4
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