diff options
| author | Nadia Derbey <Nadia.Derbey@bull.net> | 2008-07-25 12:48:01 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-07-25 21:53:42 +0400 |
| commit | f9c46d6ea5ce138a886c3a0f10a46130afab75f5 (patch) | |
| tree | 1eedc2428866fb0b3f9f864e52ffb6eaf00911a4 /include | |
| parent | 3219b3b7456d5cf15ba7b1fe7b1bcf15ce8840e2 (diff) | |
| download | linux-f9c46d6ea5ce138a886c3a0f10a46130afab75f5.tar.xz | |
idr: make idr_find rcu-safe
Make idr_find rcu-safe: it can now be called inside an rcu_read critical
section.
Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Reviewed-by: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Jim Houston <jim.houston@comcast.net>
Cc: Pierre Peiffer <peifferp@gmail.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/idr.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/include/linux/idr.h b/include/linux/idr.h index 762c3f2c631d..fa035f96f2a3 100644 --- a/include/linux/idr.h +++ b/include/linux/idr.h @@ -79,6 +79,22 @@ struct idr { #define _idr_rc_to_errno(rc) ((rc) == -1 ? -EAGAIN : -ENOSPC) +/** + * idr synchronization (stolen from radix-tree.h) + * + * idr_find() is able to be called locklessly, using RCU. The caller must + * ensure calls to this function are made within rcu_read_lock() regions. + * Other readers (lock-free or otherwise) and modifications may be running + * concurrently. + * + * It is still required that the caller manage the synchronization and + * lifetimes of the items. So if RCU lock-free lookups are used, typically + * this would mean that the items have their own locks, or are amenable to + * lock-free access; and that the items are freed by RCU (or only freed after + * having been deleted from the idr tree *and* a synchronize_rcu() grace + * period). + */ + /* * This is what we export. */ |