From: Christoph Hellwig <hch@lst.de>
Date: Tue, 12 Oct 2021 13:12:19 +0200
Subject: [PATCH] block: replace the spin argument to blk_iopoll with a flags
argument
Git-commit: ef99b2d37666b7a600baab9e1c4944436652b0a2
Patch-mainline: v5.16-rc1
References: jsc#PED-1183
Switch the boolean spin argument to blk_poll to passing a set of flags
instead. This will allow to control polling behavior in a more fine
grained way.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Link: https://lore.kernel.org/r/20211012111226.760968-10-hch@lst.de
[axboe: adapt to changed io_uring iopoll]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
block/blk-exec.c | 2 +-
block/blk-mq.c | 17 +++++++----------
block/fops.c | 8 ++++----
fs/io_uring.c | 9 +++++----
fs/iomap/direct-io.c | 6 +++---
include/linux/blkdev.h | 4 +++-
include/linux/fs.h | 2 +-
include/linux/iomap.h | 2 +-
mm/page_io.c | 2 +-
9 files changed, 26 insertions(+), 26 deletions(-)
diff --git a/block/blk-exec.c b/block/blk-exec.c
index d6cd501c0d34..1fa7f25e5726 100644
--- a/block/blk-exec.c
+++ b/block/blk-exec.c
@@ -71,7 +71,7 @@ static bool blk_rq_is_poll(struct request *rq)
static void blk_rq_poll_completion(struct request *rq, struct completion *wait)
{
do {
- blk_poll(rq->q, request_to_qc_t(rq->mq_hctx, rq), true);
+ blk_poll(rq->q, request_to_qc_t(rq->mq_hctx, rq), 0);
cond_resched();
} while (!completion_done(wait));
}
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 7d0d947921a6..6609e10657a8 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -4052,7 +4052,7 @@ static bool blk_mq_poll_hybrid(struct request_queue *q, blk_qc_t qc)
}
static int blk_mq_poll_classic(struct request_queue *q, blk_qc_t cookie,
- bool spin)
+ unsigned int flags)
{
struct blk_mq_hw_ctx *hctx = blk_qc_to_hctx(q, cookie);
long state = get_current_state();
@@ -4075,7 +4075,7 @@ static int blk_mq_poll_classic(struct request_queue *q, blk_qc_t cookie,
if (task_is_running(current))
return 1;
- if (ret < 0 || !spin)
+ if (ret < 0 || (flags & BLK_POLL_ONESHOT))
break;
cpu_relax();
} while (!need_resched());
@@ -4088,15 +4088,13 @@ static int blk_mq_poll_classic(struct request_queue *q, blk_qc_t cookie,
* blk_poll - poll for IO completions
* @q: the queue
* @cookie: cookie passed back at IO submission time
- * @spin: whether to spin for completions
+ * @flags: BLK_POLL_* flags that control the behavior
*
* Description:
* Poll for completions on the passed in queue. Returns number of
- * completed entries found. If @spin is true, then blk_poll will continue
- * looping until at least one completion is found, unless the task is
- * otherwise marked running (or we need to reschedule).
+ * completed entries found.
*/
-int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin)
+int blk_poll(struct request_queue *q, blk_qc_t cookie, unsigned int flags)
{
if (cookie == BLK_QC_T_NONE ||
!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
@@ -4105,12 +4103,11 @@ int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin)
if (current->plug)
blk_flush_plug_list(current->plug, false);
- /* If specified not to spin, we also should not sleep. */
- if (spin && q->poll_nsec != BLK_MQ_POLL_CLASSIC) {
+ if (q->poll_nsec != BLK_MQ_POLL_CLASSIC) {
if (blk_mq_poll_hybrid(q, cookie))
return 1;
}
- return blk_mq_poll_classic(q, cookie, spin);
+ return blk_mq_poll_classic(q, cookie, flags);
}
EXPORT_SYMBOL_GPL(blk_poll);
diff --git a/block/fops.c b/block/fops.c
index 15324f2e5a91..db8f2fe68dd2 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -108,7 +108,7 @@ static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb,
if (!READ_ONCE(bio.bi_private))
break;
if (!(iocb->ki_flags & IOCB_HIPRI) ||
- !blk_poll(bdev_get_queue(bdev), qc, true))
+ !blk_poll(bdev_get_queue(bdev), qc, 0))
blk_io_schedule();
}
__set_current_state(TASK_RUNNING);
@@ -141,12 +141,12 @@ struct blkdev_dio {
static struct bio_set blkdev_dio_pool;
-static int blkdev_iopoll(struct kiocb *kiocb, bool wait)
+static int blkdev_iopoll(struct kiocb *kiocb, unsigned int flags)
{
struct block_device *bdev = I_BDEV(kiocb->ki_filp->f_mapping->host);
struct request_queue *q = bdev_get_queue(bdev);
- return blk_poll(q, READ_ONCE(kiocb->ki_cookie), wait);
+ return blk_poll(q, READ_ONCE(kiocb->ki_cookie), flags);
}
static void blkdev_bio_end_io(struct bio *bio)
@@ -297,7 +297,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
if (!READ_ONCE(dio->waiter))
break;
- if (!do_poll || !blk_poll(bdev_get_queue(bdev), qc, true))
+ if (!do_poll || !blk_poll(bdev_get_queue(bdev), qc, 0))
blk_io_schedule();
}
__set_current_state(TASK_RUNNING);
diff --git a/fs/io_uring.c b/fs/io_uring.c
index d2e86788c872..541fec2bd49a 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2457,14 +2457,15 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
long min)
{
struct io_kiocb *req, *tmp;
+ unsigned int poll_flags = 0;
LIST_HEAD(done);
- bool spin;
/*
* Only spin for completions if we don't have multiple devices hanging
* off our complete list, and we're under the requested amount.
*/
- spin = !ctx->poll_multi_queue && *nr_events < min;
+ if (ctx->poll_multi_queue || *nr_events >= min)
+ poll_flags |= BLK_POLL_ONESHOT;
list_for_each_entry_safe(req, tmp, &ctx->iopoll_list, inflight_entry) {
struct kiocb *kiocb = &req->rw.kiocb;
@@ -2482,11 +2483,11 @@ static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
if (!list_empty(&done))
break;
- ret = kiocb->ki_filp->f_op->iopoll(kiocb, spin);
+ ret = kiocb->ki_filp->f_op->iopoll(kiocb, poll_flags);
if (unlikely(ret < 0))
return ret;
else if (ret)
- spin = false;
+ poll_flags |= BLK_POLL_ONESHOT;
/* iopoll may have completed current req */
if (READ_ONCE(req->iopoll_completed))
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index 560ae967f70e..236aba256cd1 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -49,13 +49,13 @@ struct iomap_dio {
};
};
-int iomap_dio_iopoll(struct kiocb *kiocb, bool spin)
+int iomap_dio_iopoll(struct kiocb *kiocb, unsigned int flags)
{
struct request_queue *q = READ_ONCE(kiocb->private);
if (!q)
return 0;
- return blk_poll(q, READ_ONCE(kiocb->ki_cookie), spin);
+ return blk_poll(q, READ_ONCE(kiocb->ki_cookie), flags);
}
EXPORT_SYMBOL_GPL(iomap_dio_iopoll);
@@ -642,7 +642,7 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
if (!(iocb->ki_flags & IOCB_HIPRI) ||
!dio->submit.last_queue ||
!blk_poll(dio->submit.last_queue,
- dio->submit.cookie, true))
+ dio->submit.cookie, 0))
blk_io_schedule();
}
__set_current_state(TASK_RUNNING);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 17705c970d7e..e177346bc020 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -564,7 +564,9 @@ extern const char *blk_op_str(unsigned int op);
int blk_status_to_errno(blk_status_t status);
blk_status_t errno_to_blk_status(int errno);
-int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin);
+/* only poll the hardware once, don't continue until a completion was found */
+#define BLK_POLL_ONESHOT (1 << 0)
+int blk_poll(struct request_queue *q, blk_qc_t cookie, unsigned int flags);
static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
{
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e7a633353fd2..c443cddf414f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2075,7 +2075,7 @@ struct file_operations {
ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
ssize_t (*read_iter) (struct kiocb *, struct iov_iter *);
ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
- int (*iopoll)(struct kiocb *kiocb, bool spin);
+ int (*iopoll)(struct kiocb *kiocb, unsigned int flags);
int (*iterate) (struct file *, struct dir_context *);
int (*iterate_shared) (struct file *, struct dir_context *);
__poll_t (*poll) (struct file *, struct poll_table_struct *);
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 24f8489583ca..1e86b65567c2 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -337,7 +337,7 @@ struct iomap_dio *__iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
unsigned int dio_flags);
ssize_t iomap_dio_complete(struct iomap_dio *dio);
-int iomap_dio_iopoll(struct kiocb *kiocb, bool spin);
+int iomap_dio_iopoll(struct kiocb *kiocb, unsigned int flags);
#ifdef CONFIG_SWAP
struct file;
diff --git a/mm/page_io.c b/mm/page_io.c
index c493ce9ebcf5..5d5543fcefa4 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -428,7 +428,7 @@ int swap_readpage(struct page *page, bool synchronous)
if (!READ_ONCE(bio->bi_private))
break;
- if (!blk_poll(disk->queue, qc, true))
+ if (!blk_poll(disk->queue, qc, 0))
blk_io_schedule();
}
__set_current_state(TASK_RUNNING);
--
2.35.3