From 83521d3eb8dd2dfb04dd78b4733e9766f61bb47e Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Sun, 30 Oct 2005 15:01:39 -0800 Subject: [PATCH] [PATCH] cfq-iosched: move tasklist walk to elevator.c We're trying to get rid of as much as possible tasklist walks, or at least moving them to core code. This patch falls into the second category. Instead of walking the tasklist in cfq-iosched move that into elv_unregister. The added benefit is that with this change the as ioscheduler might be might unloadable more easily aswell. The new code uses read_lock instead of read_lock_irq because the tasklist_lock only needs irq disabling for writers. Signed-off-by: Christoph Hellwig Acked-by: Jens Axboe Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/block/as-iosched.c | 2 +- drivers/block/cfq-iosched.c | 22 +--------------------- drivers/block/elevator.c | 21 +++++++++++++++++++++ 3 files changed, 23 insertions(+), 22 deletions(-) diff --git a/drivers/block/as-iosched.c b/drivers/block/as-iosched.c index 564172234819..c6744ff38294 100644 --- a/drivers/block/as-iosched.c +++ b/drivers/block/as-iosched.c @@ -1973,8 +1973,8 @@ static int __init as_init(void) static void __exit as_exit(void) { - kmem_cache_destroy(arq_pool); elv_unregister(&iosched_as); + kmem_cache_destroy(arq_pool); } module_init(as_init); diff --git a/drivers/block/cfq-iosched.c b/drivers/block/cfq-iosched.c index 94690e4d41e0..5281f8e70510 100644 --- a/drivers/block/cfq-iosched.c +++ b/drivers/block/cfq-iosched.c @@ -2418,28 +2418,8 @@ static int __init cfq_init(void) static void __exit cfq_exit(void) { - struct task_struct *g, *p; - unsigned long flags; - - read_lock_irqsave(&tasklist_lock, flags); - - /* - * iterate each process in the system, removing our io_context - */ - do_each_thread(g, p) { - struct io_context *ioc = p->io_context; - - if (ioc && ioc->cic) { - ioc->cic->exit(ioc->cic); - cfq_free_io_context(ioc->cic); - ioc->cic = NULL; - } - } while_each_thread(g, p); - - read_unlock_irqrestore(&tasklist_lock, flags); - - cfq_slab_kill(); elv_unregister(&iosched_cfq); + cfq_slab_kill(); } module_init(cfq_init); diff --git a/drivers/block/elevator.c b/drivers/block/elevator.c index 55621d5c5774..58e881bfd189 100644 --- a/drivers/block/elevator.c +++ b/drivers/block/elevator.c @@ -642,6 +642,27 @@ EXPORT_SYMBOL_GPL(elv_register); void elv_unregister(struct elevator_type *e) { + struct task_struct *g, *p; + + /* + * Iterate every thread in the process to remove the io contexts. + */ + read_lock(&tasklist_lock); + do_each_thread(g, p) { + struct io_context *ioc = p->io_context; + if (ioc && ioc->cic) { + ioc->cic->exit(ioc->cic); + ioc->cic->dtor(ioc->cic); + ioc->cic = NULL; + } + if (ioc && ioc->aic) { + ioc->aic->exit(ioc->aic); + ioc->aic->dtor(ioc->aic); + ioc->aic = NULL; + } + } while_each_thread(g, p); + read_unlock(&tasklist_lock); + spin_lock_irq(&elv_list_lock); list_del_init(&e->list); spin_unlock_irq(&elv_list_lock);