mm: use rlimit helpers

Make sure compiler won't do weird things with limits.  E.g.  fetching them
twice may return 2 different values after writable limits are implemented.

I.e.  either use rlimit helpers added in
3e10e716abf3c71bdb5d86b8f507f9e72236c9cd ("resource: add helpers for
fetching rlimits") or ACCESS_ONCE if not applicable.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/filemap.c b/mm/filemap.c
index 148b52a..045b31c 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1986,7 +1986,7 @@ EXPORT_SYMBOL(iov_iter_single_seg_count);
 inline int generic_write_checks(struct file *file, loff_t *pos, size_t *count, int isblk)
 {
        struct inode *inode = file->f_mapping->host;
-       unsigned long limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
+       unsigned long limit = rlimit(RLIMIT_FSIZE);
 
         if (unlikely(*pos < 0))
                 return -EINVAL;

diff --git a/mm/mlock.c b/mm/mlock.c
index 2b8335a..8f4e2df 100644 (file)
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -25,7 +25,7 @@ int can_do_mlock(void)
 {
        if (capable(CAP_IPC_LOCK))
                return 1;
-       if (current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur != 0)
+       if (rlimit(RLIMIT_MEMLOCK) != 0)
                return 1;
        return 0;
 }
@@ -487,7 +487,7 @@ SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len)
        locked = len >> PAGE_SHIFT;
        locked += current->mm->locked_vm;
 
-       lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
+       lock_limit = rlimit(RLIMIT_MEMLOCK);
        lock_limit >>= PAGE_SHIFT;
 
        /* check against resource limits */
@@ -550,7 +550,7 @@ SYSCALL_DEFINE1(mlockall, int, flags)
 
        down_write(&current->mm->mmap_sem);
 
-       lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
+       lock_limit = rlimit(RLIMIT_MEMLOCK);
        lock_limit >>= PAGE_SHIFT;
 
        ret = -ENOMEM;
@@ -584,7 +584,7 @@ int user_shm_lock(size_t size, struct user_struct *user)
        int allowed = 0;
 
        locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
-       lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
+       lock_limit = rlimit(RLIMIT_MEMLOCK);
        if (lock_limit == RLIM_INFINITY)
                allowed = 1;
        lock_limit >>= PAGE_SHIFT;
@@ -618,12 +618,12 @@ int account_locked_memory(struct mm_struct *mm, struct rlimit *rlim,
 
        down_write(&mm->mmap_sem);
 
-       lim = rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
+       lim = ACCESS_ONCE(rlim[RLIMIT_AS].rlim_cur) >> PAGE_SHIFT;
        vm   = mm->total_vm + pgsz;
        if (lim < vm)
                goto out;
 
-       lim = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
+       lim = ACCESS_ONCE(rlim[RLIMIT_MEMLOCK].rlim_cur) >> PAGE_SHIFT;
        vm   = mm->locked_vm + pgsz;
        if (lim < vm)
                goto out;

diff --git a/mm/mmap.c b/mm/mmap.c
index c646618..3165614 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -265,7 +265,7 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
         * segment grow beyond its set limit the in case where the limit is
         * not page aligned -Ram Gupta
         */
-       rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
+       rlim = rlimit(RLIMIT_DATA);
        if (rlim < RLIM_INFINITY && (brk - mm->start_brk) +
                        (mm->end_data - mm->start_data) > rlim)
                goto out;
@@ -967,7 +967,7 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
                unsigned long locked, lock_limit;
                locked = len >> PAGE_SHIFT;
                locked += mm->locked_vm;
-               lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
+               lock_limit = rlimit(RLIMIT_MEMLOCK);
                lock_limit >>= PAGE_SHIFT;
                if (locked > lock_limit && !capable(CAP_IPC_LOCK))
                        return -EAGAIN;
@@ -1594,7 +1594,7 @@ static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, uns
                return -ENOMEM;
 
        /* Stack limit test */
-       if (size > rlim[RLIMIT_STACK].rlim_cur)
+       if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur))
                return -ENOMEM;
 
        /* mlock limit tests */
@@ -1602,7 +1602,8 @@ static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, uns
                unsigned long locked;
                unsigned long limit;
                locked = mm->locked_vm + grow;
-               limit = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
+               limit = ACCESS_ONCE(rlim[RLIMIT_MEMLOCK].rlim_cur);
+               limit >>= PAGE_SHIFT;
                if (locked > limit && !capable(CAP_IPC_LOCK))
                        return -ENOMEM;
        }
@@ -2067,7 +2068,7 @@ unsigned long do_brk(unsigned long addr, unsigned long len)
                unsigned long locked, lock_limit;
                locked = len >> PAGE_SHIFT;
                locked += mm->locked_vm;
-               lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
+               lock_limit = rlimit(RLIMIT_MEMLOCK);
                lock_limit >>= PAGE_SHIFT;
                if (locked > lock_limit && !capable(CAP_IPC_LOCK))
                        return -EAGAIN;
@@ -2281,7 +2282,7 @@ int may_expand_vm(struct mm_struct *mm, unsigned long npages)
        unsigned long cur = mm->total_vm;       /* pages */
        unsigned long lim;
 
-       lim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
+       lim = rlimit(RLIMIT_AS) >> PAGE_SHIFT;
 
        if (cur + npages > lim)
                return 0;

diff --git a/mm/mremap.c b/mm/mremap.c
index 8451908..4c4c803 100644 (file)
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -285,7 +285,7 @@ static struct vm_area_struct *vma_to_resize(unsigned long addr,
        if (vma->vm_flags & VM_LOCKED) {
                unsigned long locked, lock_limit;
                locked = mm->locked_vm << PAGE_SHIFT;
-               lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
+               lock_limit = rlimit(RLIMIT_MEMLOCK);
                locked += new_len - old_len;
                if (locked > lock_limit && !capable(CAP_IPC_LOCK))
                        goto Eagain;