diff options
author | Vegard Nossum <vegard.nossum@oracle.com> | 2017-02-08 10:44:12 +1100 |
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committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2017-02-17 16:03:17 +1100 |
commit | d4ae028a920c3b938b80da163595337bdd710cb9 (patch) | |
tree | c69aba8515a3b3411961b8af4e444c02db9dd75b /include | |
parent | 5ba8974f69c28a4cd3586d66e5c376760da0f94b (diff) |
mm: add new mmget() helper
Apart from adding the helper function itself, the rest of the kernel is
converted mechanically using:
git grep -l 'atomic_inc.*mm_users' | xargs sed -i 's/atomic_inc(&\(.*\)->mm_users);/mmget\(\1\);/'
git grep -l 'atomic_inc.*mm_users' | xargs sed -i 's/atomic_inc(&\(.*\)\.mm_users);/mmget\(\&\1\);/'
This is needed for a later patch that hooks into the helper, but might be
a worthwhile cleanup on its own.
(Michal Hocko provided most of the kerneldoc comment.)
Link: http://lkml.kernel.org/r/20161218123229.22952-2-vegard.nossum@oracle.com
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/sched.h | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 7cfa5546c840..4a28deb5f210 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2948,6 +2948,27 @@ static inline void mmdrop_async(struct mm_struct *mm) } } +/** + * mmget() - Pin the address space associated with a &struct mm_struct. + * @mm: The address space to pin. + * + * Make sure that the address space of the given &struct mm_struct doesn't + * go away. This does not protect against parts of the address space being + * modified or freed, however. + * + * Never use this function to pin this address space for an + * unbounded/indefinite amount of time. + * + * Use mmput() to release the reference acquired by mmget(). + * + * See also <Documentation/vm/active_mm.txt> for an in-depth explanation + * of &mm_struct.mm_count vs &mm_struct.mm_users. + */ +static inline void mmget(struct mm_struct *mm) +{ + atomic_inc(&mm->mm_users); +} + static inline bool mmget_not_zero(struct mm_struct *mm) { return atomic_inc_not_zero(&mm->mm_users); |