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author | Tejun Heo <tj@kernel.org> | 2011-12-14 00:33:42 +0100 |
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committer | Jens Axboe <axboe@kernel.dk> | 2011-12-14 00:33:42 +0100 |
commit | 7e5a8794492e43e9eebb68a98a23be055888ccd0 (patch) | |
tree | cc049a23b2c994f910d3101860bc1c2ecb7aa35f /include/linux/iocontext.h | |
parent | 3d3c2379feb177a5fd55bb0ed76776dc9d4f3243 (diff) | |
download | linux-stable-7e5a8794492e43e9eebb68a98a23be055888ccd0.tar.gz linux-stable-7e5a8794492e43e9eebb68a98a23be055888ccd0.tar.bz2 linux-stable-7e5a8794492e43e9eebb68a98a23be055888ccd0.zip |
block, cfq: move io_cq exit/release to blk-ioc.c
With kmem_cache managed by blk-ioc, io_cq exit/release can be moved to
blk-ioc too. The odd ->io_cq->exit/release() callbacks are replaced
with elevator_ops->elevator_exit_icq_fn() with unlinking from both ioc
and q, and freeing automatically handled by blk-ioc. The elevator
operation only need to perform exit operation specific to the elevator
- in cfq's case, exiting the cfqq's.
Also, clearing of io_cq's on q detach is moved to block core and
automatically performed on elevator switch and q release.
Because the q io_cq points to might be freed before RCU callback for
the io_cq runs, blk-ioc code should remember to which cache the io_cq
needs to be freed when the io_cq is released. New field
io_cq->__rcu_icq_cache is added for this purpose. As both the new
field and rcu_head are used only after io_cq is released and the
q/ioc_node fields aren't, they are put into unions.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux/iocontext.h')
-rw-r--r-- | include/linux/iocontext.h | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h index d15ca6591f96..ac390a34c0e7 100644 --- a/include/linux/iocontext.h +++ b/include/linux/iocontext.h @@ -14,14 +14,22 @@ struct io_cq { struct request_queue *q; struct io_context *ioc; - struct list_head q_node; - struct hlist_node ioc_node; + /* + * q_node and ioc_node link io_cq through icq_list of q and ioc + * respectively. Both fields are unused once ioc_exit_icq() is + * called and shared with __rcu_icq_cache and __rcu_head which are + * used for RCU free of io_cq. + */ + union { + struct list_head q_node; + struct kmem_cache *__rcu_icq_cache; + }; + union { + struct hlist_node ioc_node; + struct rcu_head __rcu_head; + }; unsigned long changed; - struct rcu_head rcu_head; - - void (*exit)(struct io_cq *); - void (*release)(struct io_cq *); }; /* |