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charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 On Tue, Sep 02, 2025 at 09:41:55PM -0700, Caleb Sander Mateos wrote: > On Mon, Sep 1, 2025 at 3:03 AM Ming Lei wrote: > > > > Refactor auto buffer register code and prepare for supporting batch IO > > feature, and the main motivation is to put 'ublk_io' operation code > > together, so that per-io lock can be applied for the code block. > > > > The key changes are: > > - Rename ublk_auto_buf_reg() as ublk_do_auto_buf_reg() > > Thanks, the type and the function having the same name was a minor annoyance. > > > - Introduce an enum `auto_buf_reg_res` to represent the result of > > the buffer registration attempt (FAIL, FALLBACK, OK). > > - Split the existing `ublk_do_auto_buf_reg` function into two: > > - `__ublk_do_auto_buf_reg`: Performs the actual buffer registration > > and returns the `auto_buf_reg_res` status. > > - `ublk_do_auto_buf_reg`: A wrapper that calls the internal function > > and handles the I/O preparation based on the result. > > - Introduce `ublk_prep_auto_buf_reg_io` to encapsulate the logic for > > preparing the I/O for completion after buffer registration. > > - Pass the `tag` directly to `ublk_auto_buf_reg_fallback` to avoid > > recalculating it. > > > > This refactoring makes the control flow clearer and isolates the different > > stages of the auto buffer registration process. > > > > Signed-off-by: Ming Lei > > --- > > drivers/block/ublk_drv.c | 65 +++++++++++++++++++++++++++------------- > > 1 file changed, 44 insertions(+), 21 deletions(-) > > > > diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c > > index 9185978abeb7..e53f623b0efe 100644 > > --- a/drivers/block/ublk_drv.c > > +++ b/drivers/block/ublk_drv.c > > @@ -1205,17 +1205,36 @@ static inline void __ublk_abort_rq(struct ublk_queue *ubq, > > } > > > > static void > > -ublk_auto_buf_reg_fallback(const struct ublk_queue *ubq, struct ublk_io *io) > > +ublk_auto_buf_reg_fallback(const struct ublk_queue *ubq, unsigned tag) > > { > > - unsigned tag = io - ubq->ios; > > The reason to calculate the tag like this was to avoid the pointer > dereference in req->tag. But req->tag is already accessed just prior > in ublk_dispatch_req(), so it should be cached and not too expensive > to load again. Ok, one thing is that ublk_auto_buf_reg_fallback() should be called in slow path... > > > struct ublksrv_io_desc *iod = ublk_get_iod(ubq, tag); > > > > iod->op_flags |= UBLK_IO_F_NEED_REG_BUF; > > } > > > > -static bool ublk_auto_buf_reg(const struct ublk_queue *ubq, struct request *req, > > - struct ublk_io *io, struct io_uring_cmd *cmd, > > - unsigned int issue_flags) > > +enum auto_buf_reg_res { > > + AUTO_BUF_REG_FAIL, > > + AUTO_BUF_REG_FALLBACK, > > + AUTO_BUF_REG_OK, > > +}; > > nit: move this enum definition next to the function that returns it? Yeah, good point. > > > + > > +static void ublk_prep_auto_buf_reg_io(const struct ublk_queue *ubq, > > + struct request *req, struct ublk_io *io, > > + struct io_uring_cmd *cmd, bool registered) > > How about passing enum auto_buf_reg_res instead of bool registered to > avoid the duplicated == AUTO_BUF_REG_OK in the callers? OK, either way is fine for me. > > > +{ > > + if (registered) { > > + io->task_registered_buffers = 1; > > + io->buf_ctx_handle = io_uring_cmd_ctx_handle(cmd); > > + io->flags |= UBLK_IO_FLAG_AUTO_BUF_REG; > > + } > > + ublk_init_req_ref(ubq, io); > > + __ublk_prep_compl_io_cmd(io, req); > > +} > > + > > +static enum auto_buf_reg_res > > +__ublk_do_auto_buf_reg(const struct ublk_queue *ubq, struct request *req, > > + struct ublk_io *io, struct io_uring_cmd *cmd, > > + unsigned int issue_flags) > > { > > int ret; > > > > @@ -1223,29 +1242,27 @@ static bool ublk_auto_buf_reg(const struct ublk_queue *ubq, struct request *req, > > io->buf.auto_reg.index, issue_flags); > > if (ret) { > > if (io->buf.auto_reg.flags & UBLK_AUTO_BUF_REG_FALLBACK) { > > - ublk_auto_buf_reg_fallback(ubq, io); > > - return true; > > + ublk_auto_buf_reg_fallback(ubq, req->tag); > > + return AUTO_BUF_REG_FALLBACK; > > } > > blk_mq_end_request(req, BLK_STS_IOERR); > > - return false; > > + return AUTO_BUF_REG_FAIL; > > } > > > > - io->task_registered_buffers = 1; > > - io->buf_ctx_handle = io_uring_cmd_ctx_handle(cmd); > > - io->flags |= UBLK_IO_FLAG_AUTO_BUF_REG; > > - return true; > > + return AUTO_BUF_REG_OK; > > } > > > > -static bool ublk_prep_auto_buf_reg(struct ublk_queue *ubq, > > - struct request *req, struct ublk_io *io, > > - struct io_uring_cmd *cmd, > > - unsigned int issue_flags) > > +static void ublk_do_auto_buf_reg(const struct ublk_queue *ubq, struct request *req, > > + struct ublk_io *io, struct io_uring_cmd *cmd, > > + unsigned int issue_flags) > > { > > - ublk_init_req_ref(ubq, io); > > - if (ublk_support_auto_buf_reg(ubq) && ublk_rq_has_data(req)) > > - return ublk_auto_buf_reg(ubq, req, io, cmd, issue_flags); > > + enum auto_buf_reg_res res = __ublk_do_auto_buf_reg(ubq, req, io, cmd, > > + issue_flags); > > > > - return true; > > + if (res != AUTO_BUF_REG_FAIL) { > > + ublk_prep_auto_buf_reg_io(ubq, req, io, cmd, res == AUTO_BUF_REG_OK); > > + io_uring_cmd_done(cmd, UBLK_IO_RES_OK, 0, issue_flags); > > + } > > } > > > > static bool ublk_start_io(const struct ublk_queue *ubq, struct request *req, > > @@ -1318,8 +1335,14 @@ static void ublk_dispatch_req(struct ublk_queue *ubq, > > if (!ublk_start_io(ubq, req, io)) > > return; > > > > - if (ublk_prep_auto_buf_reg(ubq, req, io, io->cmd, issue_flags)) > > + if (ublk_support_auto_buf_reg(ubq) && ublk_rq_has_data(req)) { > > + struct io_uring_cmd *cmd = io->cmd; > > Don't really see the need for this intermediate variable Yes, will remove it, but the big thing is that there isn't io->cmd for BATCH_IO any more. Thanks, Ming