ublk: remove ubq checks from ublk_{get,put}_req_ref()

ublk_get_req_ref() and ublk_put_req_ref() currently call
ublk_need_req_ref(ubq) to check whether the ublk device features require
reference counting of its requests. However, all callers already know
that reference counting is required:
- __ublk_check_and_get_req() is only called from
  ublk_check_and_get_req() if user copy is enabled, and from
  ublk_register_io_buf() if zero copy is enabled
- ublk_io_release() is only called for requests registered by
  ublk_register_io_buf(), which requires zero copy
- ublk_ch_read_iter() and ublk_ch_write_iter() only call
  ublk_put_req_ref() if ublk_check_and_get_req() succeeded, which
  requires user copy to be enabled

So drop the ublk_need_req_ref() check and the ubq argument in
ublk_get_req_ref() and ublk_put_req_ref().

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250620151008.3976463-14-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index c3c0601db4871834488a948703e186b7cf633111..eec3abb78ce5ca632ee00db2c77bdc22e23e88f7 100644 (file)
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -699,24 +699,15 @@ static inline void ublk_init_req_ref(const struct ublk_queue *ubq,
                refcount_set(&io->ref, UBLK_REFCOUNT_INIT);
 }
 
-static inline bool ublk_get_req_ref(const struct ublk_queue *ubq,
-               struct ublk_io *io)
+static inline bool ublk_get_req_ref(struct ublk_io *io)
 {
-       if (ublk_need_req_ref(ubq))
-               return refcount_inc_not_zero(&io->ref);
-
-       return true;
+       return refcount_inc_not_zero(&io->ref);
 }
 
-static inline void ublk_put_req_ref(const struct ublk_queue *ubq,
-               struct ublk_io *io, struct request *req)
+static inline void ublk_put_req_ref(struct ublk_io *io, struct request *req)
 {
-       if (ublk_need_req_ref(ubq)) {
-               if (refcount_dec_and_test(&io->ref))
-                       __ublk_complete_rq(req);
-       } else {
+       if (refcount_dec_and_test(&io->ref))
                __ublk_complete_rq(req);
-       }
 }
 
 static inline void ublk_sub_req_ref(struct ublk_io *io, struct request *req)
@@ -2037,7 +2028,7 @@ static void ublk_io_release(void *priv)
        if (current == io->task && io->task_registered_buffers)
                io->task_registered_buffers--;
        else
-               ublk_put_req_ref(ubq, io, rq);
+               ublk_put_req_ref(io, rq);
 }
 
 static int ublk_register_io_buf(struct io_uring_cmd *cmd,
@@ -2059,7 +2050,7 @@ static int ublk_register_io_buf(struct io_uring_cmd *cmd,
        ret = io_buffer_register_bvec(cmd, req, ublk_io_release, index,
                                      issue_flags);
        if (ret) {
-               ublk_put_req_ref(ubq, io, req);
+               ublk_put_req_ref(io, req);
                return ret;
        }
 
@@ -2366,7 +2357,7 @@ static inline struct request *__ublk_check_and_get_req(struct ublk_device *ub,
        if (!req)
                return NULL;
 
-       if (!ublk_get_req_ref(ubq, io))
+       if (!ublk_get_req_ref(io))
                return NULL;
 
        if (unlikely(!blk_mq_request_started(req) || req->tag != tag))
@@ -2380,7 +2371,7 @@ static inline struct request *__ublk_check_and_get_req(struct ublk_device *ub,
 
        return req;
 fail_put:
-       ublk_put_req_ref(ubq, io, req);
+       ublk_put_req_ref(io, req);
        return NULL;
 }
 
@@ -2496,13 +2487,12 @@ static struct request *ublk_check_and_get_req(struct kiocb *iocb,
        *off = buf_off;
        return req;
 fail:
-       ublk_put_req_ref(ubq, *io, req);
+       ublk_put_req_ref(*io, req);
        return ERR_PTR(-EACCES);
 }
 
 static ssize_t ublk_ch_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
-       struct ublk_queue *ubq;
        struct request *req;
        struct ublk_io *io;
        size_t buf_off;
@@ -2513,15 +2503,13 @@ static ssize_t ublk_ch_read_iter(struct kiocb *iocb, struct iov_iter *to)
                return PTR_ERR(req);
 
        ret = ublk_copy_user_pages(req, buf_off, to, ITER_DEST);
-       ubq = req->mq_hctx->driver_data;
-       ublk_put_req_ref(ubq, io, req);
+       ublk_put_req_ref(io, req);
 
        return ret;
 }
 
 static ssize_t ublk_ch_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
-       struct ublk_queue *ubq;
        struct request *req;
        struct ublk_io *io;
        size_t buf_off;
@@ -2532,8 +2520,7 @@ static ssize_t ublk_ch_write_iter(struct kiocb *iocb, struct iov_iter *from)
                return PTR_ERR(req);
 
        ret = ublk_copy_user_pages(req, buf_off, from, ITER_SOURCE);
-       ubq = req->mq_hctx->driver_data;
-       ublk_put_req_ref(ubq, io, req);
+       ublk_put_req_ref(io, req);
 
        return ret;
 }