From: Kanchan Joshi <[email protected]>
To: Jens Axboe <[email protected]>
Cc: [email protected]
Subject: Re: [PATCH 2/3] nvme: use separate end IO handler for IOPOLL
Date: Sat, 3 Sep 2022 15:26:52 +0530 [thread overview]
Message-ID: <20220903095652.GB10373@test-zns> (raw)
In-Reply-To: <[email protected]>
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On Fri, Sep 02, 2022 at 05:00:51PM -0600, Jens Axboe wrote:
>Don't need to rely on the cookie or request type, set the right handler
>based on how we're handling the IO.
>
>Signed-off-by: Jens Axboe <[email protected]>
>---
> drivers/nvme/host/ioctl.c | 30 ++++++++++++++++++++++--------
> 1 file changed, 22 insertions(+), 8 deletions(-)
>
>diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
>index 7756b439a688..f34abe95821e 100644
>--- a/drivers/nvme/host/ioctl.c
>+++ b/drivers/nvme/host/ioctl.c
>@@ -385,25 +385,36 @@ static void nvme_uring_task_cb(struct io_uring_cmd *ioucmd)
> io_uring_cmd_done(ioucmd, status, result);
> }
>
>-static void nvme_uring_cmd_end_io(struct request *req, blk_status_t err)
>+static void nvme_uring_iopoll_cmd_end_io(struct request *req, blk_status_t err)
> {
> struct io_uring_cmd *ioucmd = req->end_io_data;
> struct nvme_uring_cmd_pdu *pdu = nvme_uring_cmd_pdu(ioucmd);
> /* extract bio before reusing the same field for request */
> struct bio *bio = pdu->bio;
>- void *cookie = READ_ONCE(ioucmd->cookie);
>
> pdu->req = req;
> req->bio = bio;
>
> /*
> * For iopoll, complete it directly.
>- * Otherwise, move the completion to task work.
> */
>- if (cookie != NULL && blk_rq_is_poll(req))
>- nvme_uring_task_cb(ioucmd);
>- else
>- io_uring_cmd_complete_in_task(ioucmd, nvme_uring_task_cb);
>+ nvme_uring_task_cb(ioucmd);
>+}
>+
>+static void nvme_uring_cmd_end_io(struct request *req, blk_status_t err)
>+{
>+ struct io_uring_cmd *ioucmd = req->end_io_data;
>+ struct nvme_uring_cmd_pdu *pdu = nvme_uring_cmd_pdu(ioucmd);
>+ /* extract bio before reusing the same field for request */
>+ struct bio *bio = pdu->bio;
>+
>+ pdu->req = req;
>+ req->bio = bio;
>+
>+ /*
>+ * Move the completion to task work.
>+ */
>+ io_uring_cmd_complete_in_task(ioucmd, nvme_uring_task_cb);
> }
>
> static int nvme_uring_cmd_io(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
>@@ -464,7 +475,10 @@ static int nvme_uring_cmd_io(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
> blk_flags);
> if (IS_ERR(req))
> return PTR_ERR(req);
>- req->end_io = nvme_uring_cmd_end_io;
>+ if (issue_flags & IO_URING_F_IOPOLL)
>+ req->end_io = nvme_uring_iopoll_cmd_end_io;
>+ else
>+ req->end_io = nvme_uring_cmd_end_io;
The polled handler (nvme_uring_iopoll_cmd_end_io) may get called in irq
context (some swapper/kworker etc.) too. And in that case will it be
safe to call nvme_uring_task_cb directly.
We don't touch the user-fields in cmd (thanks to Big CQE) so that part is
sorted. But there is blk_rq_unmap_user call - can that or anything else
inside io_req_complete_post() cause trouble.
* A matching blk_rq_unmap_user() must be issued at the end of I/O, while
* still in process context.
*/
int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
struct rq_map_data *map_data,
const struct iov_iter *iter, gfp_t gfp_mask)
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next prev parent reply other threads:[~2022-09-03 10:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-02 23:00 [PATCHSET 0/3] Fixups/improvements for iopoll passthrough Jens Axboe
2022-09-02 23:00 ` [PATCH 1/3] io_uring: cleanly separate request types for iopoll Jens Axboe
2022-09-02 23:00 ` [PATCH 2/3] nvme: use separate end IO handler for IOPOLL Jens Axboe
2022-09-03 9:56 ` Kanchan Joshi [this message]
2022-09-03 15:23 ` Jens Axboe
2022-09-02 23:00 ` [PATCH 3/3] fs: add batch and poll flags to the uring_cmd_iopoll() handler Jens Axboe
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