[PATCH 4/4] direct-io: get rid of irq flag saving where it isn't needed

Jens Axboe
2009-08-18T08:35:07Z

We use the flags saving variant of the spin lock functions everywhere
in fs/direct-io.c, even in places where we otherwise block. Get rid
of that except for the end_io path, which may indeed be called with
irqs disabled.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---
fs/direct-io.c | 24 ++++++++++--------------
1 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/fs/direct-io.c b/fs/direct-io.c
index 0e923f2..2f73593 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -259,13 +259,12 @@ dio_bio_alloc(struct dio *dio, struct block_device *bdev,
static void dio_bio_submit(struct dio *dio)
{
struct bio *bio = dio->bio;
- unsigned long flags;

bio->bi_private = dio;

- spin_lock_irqsave(&dio->bio_lock, flags);
+ spin_lock_irq(&dio->bio_lock);
dio->refcount++;
- spin_unlock_irqrestore(&dio->bio_lock, flags);
+ spin_unlock_irq(&dio->bio_lock);

if (dio->is_async && dio->rw == READ)
bio_set_pages_dirty(bio);
@@ -295,10 +294,9 @@ static void dio_cleanup(struct dio *dio)
*/
static struct bio *dio_await_one(struct dio *dio)
{
- unsigned long flags;
struct bio *bio = NULL;

- spin_lock_irqsave(&dio->bio_lock, flags);
+ spin_lock_irq(&dio->bio_lock);

/*
* Wait as long as the list is empty and there are bios in flight. bio
@@ -309,17 +307,17 @@ static struct bio *dio_await_one(struct dio *dio)
while (dio->refcount > 1 && dio->bio_list == NULL) {
__set_current_state(TASK_UNINTERRUPTIBLE);
dio->waiter = current;
- spin_unlock_irqrestore(&dio->bio_lock, flags);
+ spin_unlock_irq(&dio->bio_lock);
io_schedule();
/* wake up sets us TASK_RUNNING */
- spin_lock_irqsave(&dio->bio_lock, flags);
+ spin_lock_irq(&dio->bio_lock);
dio->waiter = NULL;
}
if (dio->bio_list) {
bio = dio->bio_list;
dio->bio_list = bio->bi_private;
}
- spin_unlock_irqrestore(&dio->bio_lock, flags);
+ spin_unlock_irq(&dio->bio_lock);
return bio;
}

@@ -388,14 +386,13 @@ static int dio_bio_reap(struct dio *dio)

if (dio->reap_counter++ >= 64) {
while (dio->bio_list) {
- unsigned long flags;
struct bio *bio;
int ret2;

- spin_lock_irqsave(&dio->bio_lock, flags);
+ spin_lock_irq(&dio->bio_lock);
bio = dio->bio_list;
dio->bio_list = bio->bi_private;
- spin_unlock_irqrestore(&dio->bio_lock, flags);
+ spin_unlock_irq(&dio->bio_lock);
ret2 = dio_bio_complete(dio, bio);
if (ret == 0)
ret = ret2;
@@ -870,7 +867,6 @@ direct_io_worker(struct kiocb *iocb, struct inode *inode,
struct dio_args *args, unsigned blkbits, get_block_t get_block,
dio_iodone_t end_io, struct dio *dio)
{
- unsigned long flags;
int rw = args->rw;
ssize_t ret = 0;
ssize_t ret2;
@@ -984,9 +980,9 @@ direct_io_worker(struct kiocb *iocb, struct inode *inode,
* completion paths can drop their ref and use the remaining count to
* decide to wake the submission path atomically.
*/
- spin_lock_irqsave(&dio->bio_lock, flags);
+ spin_lock_irq(&dio->bio_lock);
ret2 = --dio->refcount;
- spin_unlock_irqrestore(&dio->bio_lock, flags);
+ spin_unlock_irq(&dio->bio_lock);

if (ret2 == 0) {
ret = dio_complete(dio, args->offset, ret);
--
1.6.4.53.g3f55e