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mm: use rlimit helpers
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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
3e10e71 ("resource: add helpers for
fetching rlimits") or ACCESS_ONCE if not applicable.

Signed-off-by: Jiri Slaby <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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@torvalds
Jiri Slaby authored and torvalds committed Mar 6, 2010
1 parent 06f9d8c commit 59e99e5
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Showing 4 changed files with 15 additions and 14 deletions.
2 changes: 1 addition & 1 deletion mm/filemap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
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12 changes: 6 additions & 6 deletions mm/mlock.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
}
Expand Down Expand Up @@ -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 */
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
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13 changes: 7 additions & 6 deletions mm/mmap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -1594,15 +1594,16 @@ 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 */
if (vma->vm_flags & VM_LOCKED) {
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;
}
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
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2 changes: 1 addition & 1 deletion mm/mremap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
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