[PATCH] stop elv_unregister() from rogering other iosched's data, fix locking

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 8 insertions, 0 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 521c56d4fdbc..7102bafc98b3 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1211,6 +1211,13 @@ static void cfq_free_io_context(struct cfq_io_context *cic)
         kmem_cache_free(cfq_ioc_pool, cic);
 }
 
+static void cfq_trim(struct io_context *ioc)
+{
+        ioc->set_ioprio = NULL;
+        if (ioc->cic)
+                cfq_free_io_context(ioc->cic);
+}
+
 /*
  * Called with interrupts disabled
  */
@@ -2472,6 +2479,7 @@ static struct elevator_type iosched_cfq = {
                 .elevator_may_queue_fn =        cfq_may_queue,
                 .elevator_init_fn =             cfq_init_queue,
                 .elevator_exit_fn =             cfq_exit_queue,
+                .trim =                         cfq_trim,
         },
         .elevator_ktype =       &cfq_ktype,
         .elevator_name =        "cfq",