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authorOleg Nesterov <oleg@tv-sign.ru>2006-08-21 08:34:15 +0200
committerJens Axboe <axboe@suse.de>2006-08-21 08:34:15 +0200
commit9f83e45eb54fc7198dc59fc63255341851ba4c48 (patch)
tree3874581e08052b7f37f164110b3bd44ae5eff291 /block
parent78bd4d484f81a611ef6ff02f909e576cb9aac7f2 (diff)
downloadlinux-linaro-stable-9f83e45eb54fc7198dc59fc63255341851ba4c48.tar.gz
[PATCH] Fix current_io_context() vs set_task_ioprio() race
I know nothing about io scheduler, but I suspect set_task_ioprio() is not safe. current_io_context() initializes "struct io_context", then sets ->io_context. set_task_ioprio() running on another cpu may see the changes out of order, so ->set_ioprio(ioc) may use io_context which was not initialized properly. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Jens Axboe <axboe@suse.de>
Diffstat (limited to 'block')
-rw-r--r--block/ll_rw_blk.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 61d6b3c65b66..ddd9253f9d55 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -3628,6 +3628,8 @@ struct io_context *current_io_context(gfp_t gfp_flags)
ret->nr_batch_requests = 0; /* because this is 0 */
ret->aic = NULL;
ret->cic_root.rb_node = NULL;
+ /* make sure set_task_ioprio() sees the settings above */
+ smp_wmb();
tsk->io_context = ret;
}