[PATCH 2/8] block: wire up block device ->iopoll()

[Jens Axboe]

Signed-off-by: Jens Axboe <ax...@kernel.dk>
---
 fs/block_dev.c | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index d233a59ea364..711cd5a3469e 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -273,6 +273,7 @@ struct blkdev_dio {
        };
        size_t                  size;
        atomic_t                ref;
+       blk_qc_t                qc;
        bool                    multi_bio : 1;
        bool                    should_dirty : 1;
        bool                    is_sync : 1;
@@ -281,6 +282,21 @@ struct blkdev_dio {
 
 static struct bio_set blkdev_dio_pool;
 
+static int blkdev_iopoll(struct kiocb *kiocb, bool wait)
+{
+       struct blkdev_dio *dio = READ_ONCE(kiocb->private);
+
+       /* dio can be NULL here, if the IO hasn't been submitted yet */
+       if (dio) {
+               struct block_device *bdev;
+
+               bdev = I_BDEV(kiocb->ki_filp->f_mapping->host);
+               return blk_poll(bdev_get_queue(bdev), READ_ONCE(dio->qc), wait);
+       }
+
+       return 0;
+}
+
 static void blkdev_bio_end_io(struct bio *bio)
 {
        struct blkdev_dio *dio = bio->bi_private;
@@ -335,7 +351,6 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter 
*iter, int nr_pages)
        bool is_poll = (iocb->ki_flags & IOCB_HIPRI) != 0;
        bool is_read = (iov_iter_rw(iter) == READ), is_sync;
        loff_t pos = iocb->ki_pos;
-       blk_qc_t qc = BLK_QC_T_NONE;
        int ret = 0;
 
        if ((pos | iov_iter_alignment(iter)) &
@@ -355,6 +370,9 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter 
*iter, int nr_pages)
        dio->size = 0;
        dio->multi_bio = false;
        dio->should_dirty = is_read && iter_is_iovec(iter);
+       dio->qc = BLK_QC_T_NONE;
+
+       WRITE_ONCE(iocb->private, dio);
 
        /*
         * Don't plug for HIPRI/polled IO, as those should go straight
@@ -395,7 +413,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter 
*iter, int nr_pages)
                        if (iocb->ki_flags & IOCB_HIPRI)
                                bio->bi_opf |= REQ_HIPRI;
 
-                       qc = submit_bio(bio);
+                       dio->qc = submit_bio(bio);
                        break;
                }
 
@@ -423,7 +441,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter 
*iter, int nr_pages)
                        break;
 
                if (!(iocb->ki_flags & IOCB_HIPRI) ||
-                   !blk_poll(bdev_get_queue(bdev), qc, true))
+                   !blk_poll(bdev_get_queue(bdev), dio->qc, true))
                        io_schedule();
        }
        __set_current_state(TASK_RUNNING);
@@ -2061,6 +2079,7 @@ const struct file_operations def_blk_fops = {
        .llseek         = block_llseek,
        .read_iter      = blkdev_read_iter,
        .write_iter     = blkdev_write_iter,
+       .iopoll         = blkdev_iopoll,
        .mmap           = generic_file_mmap,
        .fsync          = blkdev_fsync,
        .unlocked_ioctl = block_ioctl,
-- 
2.17.1