[PATCH 11/14] ipc: teach the mm about range locking

[Davidlohr Bueso]

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 <dbu...@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