[PATCH 5/5] block: enable use of bio allocation cache

Jens Axboe
2021-08-10T16:37:45Z

If the kiocb passed in has a bio cache specified, then use that to
allocate a (and free) new bio if possible.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/block_dev.c | 32 ++++++++++++++++++++++++++++----
1 file changed, 28 insertions(+), 4 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 9ef4f1fc2cb0..a192c5672430 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -327,6 +327,14 @@ static int blkdev_iopoll(struct kiocb *kiocb, bool wait)
return blk_poll(q, READ_ONCE(kiocb->ki_cookie), wait);
}

+static void dio_bio_put(struct blkdev_dio *dio)
+{
+ if (dio->iocb->ki_flags & IOCB_ALLOC_CACHE)
+ bio_cache_put(dio->iocb->ki_bio_cache, &dio->bio);
+ else
+ bio_put(&dio->bio);
+}
+
static void blkdev_bio_end_io(struct bio *bio)
{
struct blkdev_dio *dio = bio->bi_private;
@@ -362,7 +370,7 @@ static void blkdev_bio_end_io(struct bio *bio)
bio_check_pages_dirty(bio);
} else {
bio_release_pages(bio, false);
- bio_put(bio);
+ dio_bio_put(dio);
}
}

@@ -385,7 +393,15 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
(bdev_logical_block_size(bdev) - 1))
return -EINVAL;

- bio = bio_alloc_bioset(GFP_KERNEL, nr_pages, &blkdev_dio_pool);
+ bio = NULL;
+ if (iocb->ki_flags & IOCB_ALLOC_CACHE) {
+ bio = bio_cache_get(iocb->ki_bio_cache, GFP_KERNEL, nr_pages,
+ &blkdev_dio_pool);
+ if (!bio)
+ iocb->ki_flags &= ~IOCB_ALLOC_CACHE;
+ }
+ if (!bio)
+ bio = bio_alloc_bioset(GFP_KERNEL, nr_pages, &blkdev_dio_pool);

dio = container_of(bio, struct blkdev_dio, bio);
dio->is_sync = is_sync = is_sync_kiocb(iocb);
@@ -467,7 +483,15 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
}

submit_bio(bio);
- bio = bio_alloc(GFP_KERNEL, nr_pages);
+ bio = NULL;
+ if (iocb->ki_flags & IOCB_ALLOC_CACHE) {
+ bio = bio_cache_get(iocb->ki_bio_cache, GFP_KERNEL,
+ nr_pages, &fs_bio_set);
+ if (!bio)
+ iocb->ki_flags &= ~IOCB_ALLOC_CACHE;
+ }
+ if (!bio)
+ bio = bio_alloc(GFP_KERNEL, nr_pages);
}

if (!is_poll)
@@ -492,7 +516,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
if (likely(!ret))
ret = dio->size;

- bio_put(&dio->bio);
+ dio_bio_put(dio);
return ret;
}

--
2.32.0