[PATCH v5 0/4] io_uring: extend bvec registration

[PATCH v5 0/4] io_uring: extend bvec registration

[Joanne Koong]

This series refactors and extends the io_uring registered buffers
infrastructure to allow external subsystems to register pre-existing bvec
arrays directly.

The motivation for the patches in this series is to make fuse zero-copy
possible. These patches are split out from a previous larger
fuse-over-io_uring series [1]. The fuse zero-copy work that builds on top of
this is in [2].

Thanks,
Joanne

[1] https://lore.kernel.org/linux-fsdevel/20260116233044.1532965-1-joannelkoong@gmail.com/
[2] https://lore.kernel.org/linux-fsdevel/20260324224532.3733468-9-joannelkoong@gmail.com/

Changelog:
v4: https://lore.kernel.org/io-uring/20260327172631.3380702-1-joannelkoong@gmail.com/
v4 -> v5:
* rebase to origin/for-7.1/io_uring 
* drop the io_uring_registered_mem_region_get() patch

v3: https://lore.kernel.org/io-uring/20260324221426.3436334-1-joannelkoong@gmail.com/ 
v3 -> v4:
* Add comment about io_uring_registered_mem_region_get() locking (Jens)
* Return info in a new struct io_uring_mem_region_info (Jens)

v2: https://lore.kernel.org/io-uring/20260324182157.990864-1-joannelkoong@gmail.com/
v2 -> v3:
* drop patch that makes buffer release callback optional
* add patch for renaming/exporting IO_IMU_DEST / IO_IMU_SOURCE

v1: https://lore.kernel.org/io-uring/20260324001007.1144471-1-joannelkoong@gmail.com/
v1 -> v2:
* update io_kernel_buffer_init() to take bitmasked dir directly so callers can
  set both dest and source

Joanne Koong (4):
  io_uring/rsrc: rename
    io_buffer_register_bvec()/io_buffer_unregister_bvec()
  io_uring/rsrc: split io_buffer_register_request() logic
  io_uring/rsrc: add io_buffer_register_bvec()
  io_uring/rsrc: rename and export IO_IMU_DEST / IO_IMU_SOURCE

 Documentation/block/ublk.rst   |  14 ++--
 drivers/block/ublk_drv.c       |  22 +++---
 include/linux/io_uring/cmd.h   |  38 ++++++++--
 include/linux/io_uring_types.h |   5 ++
 io_uring/io_uring.c            |   2 +-
 io_uring/rsrc.c                | 127 +++++++++++++++++++++++----------
 io_uring/rsrc.h                |   5 --
 7 files changed, 146 insertions(+), 67 deletions(-)

-- 
2.52.0

[PATCH v5 1/4] io_uring/rsrc: rename io_buffer_register_bvec()/io_buffer_unregister_bvec()

[Joanne Koong]

Currently, io_buffer_register_bvec() takes in a request. In preparation
for supporting kernel-populated buffers in fuse io-uring (which will
need to register bvecs directly, not through a struct request), rename
this to io_buffer_register_request().

A subsequent patch will commandeer the "io_buffer_register_bvec()"
function name to support registering bvecs directly.

Rename io_buffer_unregister_bvec() to a more generic name,
io_buffer_unregister(), as both io_buffer_register_request() and
io_buffer_register_bvec() callers will use it for unregistration.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>
---
 Documentation/block/ublk.rst | 14 +++++++-------
 drivers/block/ublk_drv.c     | 22 +++++++++++-----------
 include/linux/io_uring/cmd.h | 25 +++++++++++++++++++------
 io_uring/rsrc.c              | 14 +++++++-------
 4 files changed, 44 insertions(+), 31 deletions(-)

diff --git a/Documentation/block/ublk.rst b/Documentation/block/ublk.rst
index 6ad28039663d..f014d1d69019 100644
--- a/Documentation/block/ublk.rst
+++ b/Documentation/block/ublk.rst
@@ -382,17 +382,17 @@ Zero copy
 ---------
 
 ublk zero copy relies on io_uring's fixed kernel buffer, which provides
-two APIs: `io_buffer_register_bvec()` and `io_buffer_unregister_bvec`.
+two APIs: `io_buffer_register_request()` and `io_buffer_unregister`.
 
 ublk adds IO command of `UBLK_IO_REGISTER_IO_BUF` to call
-`io_buffer_register_bvec()` for ublk server to register client request
+`io_buffer_register_request()` for ublk server to register client request
 buffer into io_uring buffer table, then ublk server can submit io_uring
 IOs with the registered buffer index. IO command of `UBLK_IO_UNREGISTER_IO_BUF`
-calls `io_buffer_unregister_bvec()` to unregister the buffer, which is
-guaranteed to be live between calling `io_buffer_register_bvec()` and
-`io_buffer_unregister_bvec()`. Any io_uring operation which supports this
-kind of kernel buffer will grab one reference of the buffer until the
-operation is completed.
+calls `io_buffer_unregister()` to unregister the buffer, which is guaranteed
+to be live between calling `io_buffer_register_request()` and
+`io_buffer_unregister()`. Any io_uring operation which supports this kind of
+kernel buffer will grab one reference of the buffer until the operation is
+completed.
 
 ublk server implementing zero copy or user copy has to be CAP_SYS_ADMIN and
 be trusted, because it is ublk server's responsibility to make sure IO buffer
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 004f367243b6..b9f293261240 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -1627,8 +1627,8 @@ ublk_auto_buf_register(const struct ublk_queue *ubq, struct request *req,
 {
 	int ret;
 
-	ret = io_buffer_register_bvec(cmd, req, ublk_io_release,
-				      io->buf.auto_reg.index, issue_flags);
+	ret = io_buffer_register_request(cmd, req, ublk_io_release,
+					 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, req->tag);
@@ -1868,7 +1868,7 @@ static int __ublk_batch_dispatch(struct ublk_queue *ubq,
 			ublk_io_unlock(io);
 
 			if (index != -1)
-				io_buffer_unregister_bvec(data->cmd, index,
+				io_buffer_unregister(data->cmd, index,
 						data->issue_flags);
 		}
 
@@ -3091,8 +3091,8 @@ static int ublk_register_io_buf(struct io_uring_cmd *cmd,
 	if (!req)
 		return -EINVAL;
 
-	ret = io_buffer_register_bvec(cmd, req, ublk_io_release, index,
-				      issue_flags);
+	ret = io_buffer_register_request(cmd, req, ublk_io_release, index,
+					 issue_flags);
 	if (ret) {
 		ublk_put_req_ref(io, req);
 		return ret;
@@ -3123,8 +3123,8 @@ ublk_daemon_register_io_buf(struct io_uring_cmd *cmd,
 	if (!ublk_dev_support_zero_copy(ub) || !ublk_rq_has_data(req))
 		return -EINVAL;
 
-	ret = io_buffer_register_bvec(cmd, req, ublk_io_release, index,
-				      issue_flags);
+	ret = io_buffer_register_request(cmd, req, ublk_io_release, index,
+					 issue_flags);
 	if (ret)
 		return ret;
 
@@ -3139,7 +3139,7 @@ static int ublk_unregister_io_buf(struct io_uring_cmd *cmd,
 	if (!(ub->dev_info.flags & UBLK_F_SUPPORT_ZERO_COPY))
 		return -EINVAL;
 
-	return io_buffer_unregister_bvec(cmd, index, issue_flags);
+	return io_buffer_unregister(cmd, index, issue_flags);
 }
 
 static int ublk_check_fetch_buf(const struct ublk_device *ub, __u64 buf_addr)
@@ -3280,7 +3280,7 @@ static int ublk_ch_uring_cmd_local(struct io_uring_cmd *cmd,
 		goto out;
 
 	/*
-	 * io_buffer_unregister_bvec() doesn't access the ubq or io,
+	 * io_buffer_unregister() doesn't access the ubq or io,
 	 * so no need to validate the q_id, tag, or task
 	 */
 	if (_IOC_NR(cmd_op) == UBLK_IO_UNREGISTER_IO_BUF)
@@ -3347,7 +3347,7 @@ static int ublk_ch_uring_cmd_local(struct io_uring_cmd *cmd,
 		req = ublk_fill_io_cmd(io, cmd);
 		ret = ublk_config_io_buf(ub, io, cmd, addr, &buf_idx);
 		if (buf_idx != UBLK_INVALID_BUF_IDX)
-			io_buffer_unregister_bvec(cmd, buf_idx, issue_flags);
+			io_buffer_unregister(cmd, buf_idx, issue_flags);
 		compl = ublk_need_complete_req(ub, io);
 
 		if (req_op(req) == REQ_OP_ZONE_APPEND)
@@ -3682,7 +3682,7 @@ static int ublk_batch_commit_io(struct ublk_queue *ubq,
 	}
 
 	if (buf_idx != UBLK_INVALID_BUF_IDX)
-		io_buffer_unregister_bvec(data->cmd, buf_idx, data->issue_flags);
+		io_buffer_unregister(data->cmd, buf_idx, data->issue_flags);
 	if (req_op(req) == REQ_OP_ZONE_APPEND)
 		req->__sector = ublk_batch_zone_lba(uc, elem);
 	if (compl)
diff --git a/include/linux/io_uring/cmd.h b/include/linux/io_uring/cmd.h
index 331dcbefe72f..bbf57da1e4c8 100644
--- a/include/linux/io_uring/cmd.h
+++ b/include/linux/io_uring/cmd.h
@@ -91,6 +91,11 @@ struct io_br_sel io_uring_cmd_buffer_select(struct io_uring_cmd *ioucmd,
 bool io_uring_mshot_cmd_post_cqe(struct io_uring_cmd *ioucmd,
 				 struct io_br_sel *sel, unsigned int issue_flags);
 
+int io_buffer_register_request(struct io_uring_cmd *cmd, struct request *rq,
+			       void (*release)(void *), unsigned int index,
+			       unsigned int issue_flags);
+int io_buffer_unregister(struct io_uring_cmd *cmd, unsigned int index,
+			 unsigned int issue_flags);
 #else
 static inline int
 io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
@@ -133,6 +138,20 @@ static inline bool io_uring_mshot_cmd_post_cqe(struct io_uring_cmd *ioucmd,
 {
 	return true;
 }
+static inline int io_buffer_register_request(struct io_uring_cmd *cmd,
+					     struct request *rq,
+					     void (*release)(void *),
+					     unsigned int index,
+					     unsigned int issue_flags)
+{
+	return -EOPNOTSUPP;
+}
+static inline int io_buffer_unregister(struct io_uring_cmd *cmd,
+				       unsigned int index,
+				       unsigned int issue_flags)
+{
+	return -EOPNOTSUPP;
+}
 #endif
 
 static inline struct io_uring_cmd *io_uring_cmd_from_tw(struct io_tw_req tw_req)
@@ -182,10 +201,4 @@ static inline void io_uring_cmd_done32(struct io_uring_cmd *ioucmd, s32 ret,
 	return __io_uring_cmd_done(ioucmd, ret, res2, issue_flags, true);
 }
 
-int io_buffer_register_bvec(struct io_uring_cmd *cmd, struct request *rq,
-			    void (*release)(void *), unsigned int index,
-			    unsigned int issue_flags);
-int io_buffer_unregister_bvec(struct io_uring_cmd *cmd, unsigned int index,
-			      unsigned int issue_flags);
-
 #endif /* _LINUX_IO_URING_CMD_H */
diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index 2d8be5edbbf6..ed5018c69d8d 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -924,9 +924,9 @@ int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
 	return ret;
 }
 
-int io_buffer_register_bvec(struct io_uring_cmd *cmd, struct request *rq,
-			    void (*release)(void *), unsigned int index,
-			    unsigned int issue_flags)
+int io_buffer_register_request(struct io_uring_cmd *cmd, struct request *rq,
+			       void (*release)(void *), unsigned int index,
+			       unsigned int issue_flags)
 {
 	struct io_ring_ctx *ctx = cmd_to_io_kiocb(cmd)->ctx;
 	struct io_rsrc_data *data = &ctx->buf_table;
@@ -986,10 +986,10 @@ int io_buffer_register_bvec(struct io_uring_cmd *cmd, struct request *rq,
 	io_ring_submit_unlock(ctx, issue_flags);
 	return ret;
 }
-EXPORT_SYMBOL_GPL(io_buffer_register_bvec);
+EXPORT_SYMBOL_GPL(io_buffer_register_request);
 
-int io_buffer_unregister_bvec(struct io_uring_cmd *cmd, unsigned int index,
-			      unsigned int issue_flags)
+int io_buffer_unregister(struct io_uring_cmd *cmd, unsigned int index,
+			 unsigned int issue_flags)
 {
 	struct io_ring_ctx *ctx = cmd_to_io_kiocb(cmd)->ctx;
 	struct io_rsrc_data *data = &ctx->buf_table;
@@ -1019,7 +1019,7 @@ int io_buffer_unregister_bvec(struct io_uring_cmd *cmd, unsigned int index,
 	io_ring_submit_unlock(ctx, issue_flags);
 	return ret;
 }
-EXPORT_SYMBOL_GPL(io_buffer_unregister_bvec);
+EXPORT_SYMBOL_GPL(io_buffer_unregister);
 
 static int validate_fixed_range(u64 buf_addr, size_t len,
 				const struct io_mapped_ubuf *imu)
-- 
2.52.0

[PATCH v5 2/4] io_uring/rsrc: split io_buffer_register_request() logic

[Joanne Koong]

Split the main initialization logic in io_buffer_register_request() into
a helper function.

This is a preparatory patch for supporting kernel-populated buffers in
fuse io-uring, which will be reusing this logic.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>
---
 io_uring/rsrc.c | 84 ++++++++++++++++++++++++++++++-------------------
 1 file changed, 51 insertions(+), 33 deletions(-)

diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index ed5018c69d8d..5384fbbf684e 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -924,64 +924,82 @@ int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
 	return ret;
 }
 
-int io_buffer_register_request(struct io_uring_cmd *cmd, struct request *rq,
-			       void (*release)(void *), unsigned int index,
-			       unsigned int issue_flags)
+static struct io_mapped_ubuf *io_kernel_buffer_init(struct io_ring_ctx *ctx,
+						    unsigned int nr_bvecs,
+						    unsigned int total_bytes,
+						    u8 dir,
+						    void (*release)(void *),
+						    void *priv,
+						    unsigned int index)
 {
-	struct io_ring_ctx *ctx = cmd_to_io_kiocb(cmd)->ctx;
 	struct io_rsrc_data *data = &ctx->buf_table;
-	struct req_iterator rq_iter;
 	struct io_mapped_ubuf *imu;
 	struct io_rsrc_node *node;
-	struct bio_vec bv;
-	unsigned int nr_bvecs = 0;
-	int ret = 0;
 
-	io_ring_submit_lock(ctx, issue_flags);
-	if (index >= data->nr) {
-		ret = -EINVAL;
-		goto unlock;
-	}
+	if (index >= data->nr)
+		return ERR_PTR(-EINVAL);
 	index = array_index_nospec(index, data->nr);
 
-	if (data->nodes[index]) {
-		ret = -EBUSY;
-		goto unlock;
-	}
+	if (data->nodes[index])
+		return ERR_PTR(-EBUSY);
 
 	node = io_rsrc_node_alloc(ctx, IORING_RSRC_BUFFER);
-	if (!node) {
-		ret = -ENOMEM;
-		goto unlock;
-	}
+	if (!node)
+		return ERR_PTR(-ENOMEM);
 
-	/*
-	 * blk_rq_nr_phys_segments() may overestimate the number of bvecs
-	 * but avoids needing to iterate over the bvecs
-	 */
-	imu = io_alloc_imu(ctx, blk_rq_nr_phys_segments(rq));
+	imu = io_alloc_imu(ctx, nr_bvecs);
 	if (!imu) {
 		io_cache_free(&ctx->node_cache, node);
-		ret = -ENOMEM;
-		goto unlock;
+		return ERR_PTR(-ENOMEM);
 	}
 
 	imu->ubuf = 0;
-	imu->len = blk_rq_bytes(rq);
+	imu->len = total_bytes;
 	imu->acct_pages = 0;
 	imu->folio_shift = PAGE_SHIFT;
+	imu->nr_bvecs = nr_bvecs;
 	refcount_set(&imu->refs, 1);
 	imu->release = release;
-	imu->priv = rq;
+	imu->priv = priv;
+	imu->dir = dir;
 	imu->flags = IO_REGBUF_F_KBUF;
-	imu->dir = 1 << rq_data_dir(rq);
 
+	node->buf = imu;
+	data->nodes[index] = node;
+
+	return imu;
+}
+
+int io_buffer_register_request(struct io_uring_cmd *cmd, struct request *rq,
+			       void (*release)(void *), unsigned int index,
+			       unsigned int issue_flags)
+{
+	struct io_ring_ctx *ctx = cmd_to_io_kiocb(cmd)->ctx;
+	struct req_iterator rq_iter;
+	struct io_mapped_ubuf *imu;
+	struct bio_vec bv;
+	/*
+	 * blk_rq_nr_phys_segments() may overestimate the number of bvecs
+	 * but avoids needing to iterate over the bvecs
+	 */
+	unsigned int nr_bvecs = blk_rq_nr_phys_segments(rq);
+	unsigned int total_bytes = blk_rq_bytes(rq);
+	int ret = 0;
+
+	io_ring_submit_lock(ctx, issue_flags);
+
+	imu = io_kernel_buffer_init(ctx, nr_bvecs, total_bytes,
+				    1 << rq_data_dir(rq), release, rq, index);
+	if (IS_ERR(imu)) {
+		ret = PTR_ERR(imu);
+		goto unlock;
+	}
+
+	nr_bvecs = 0;
 	rq_for_each_bvec(bv, rq, rq_iter)
 		imu->bvec[nr_bvecs++] = bv;
 	imu->nr_bvecs = nr_bvecs;
 
-	node->buf = imu;
-	data->nodes[index] = node;
 unlock:
 	io_ring_submit_unlock(ctx, issue_flags);
 	return ret;
-- 
2.52.0

[PATCH v5 3/4] io_uring/rsrc: add io_buffer_register_bvec()

[Joanne Koong]

Add io_buffer_register_bvec() for registering a bvec array.

This is a preparatory patch for fuse-over-io-uring zero-copy.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>
---
 include/linux/io_uring/cmd.h | 13 +++++++++++++
 io_uring/rsrc.c              | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/include/linux/io_uring/cmd.h b/include/linux/io_uring/cmd.h
index bbf57da1e4c8..42801f0b6456 100644
--- a/include/linux/io_uring/cmd.h
+++ b/include/linux/io_uring/cmd.h
@@ -94,6 +94,10 @@ bool io_uring_mshot_cmd_post_cqe(struct io_uring_cmd *ioucmd,
 int io_buffer_register_request(struct io_uring_cmd *cmd, struct request *rq,
 			       void (*release)(void *), unsigned int index,
 			       unsigned int issue_flags);
+int io_buffer_register_bvec(struct io_uring_cmd *cmd, const struct bio_vec *bvs,
+			    unsigned int nr_bvecs, void (*release)(void *),
+			    void *priv, u8 dir, unsigned int index,
+			    unsigned int issue_flags);
 int io_buffer_unregister(struct io_uring_cmd *cmd, unsigned int index,
 			 unsigned int issue_flags);
 #else
@@ -146,6 +150,15 @@ static inline int io_buffer_register_request(struct io_uring_cmd *cmd,
 {
 	return -EOPNOTSUPP;
 }
+static inline int io_buffer_register_bvec(struct io_uring_cmd *cmd,
+					  const struct bio_vec *bvs,
+					  unsigned int nr_bvecs,
+					  void (*release)(void *), void *priv,
+					  u8 dir, unsigned int index,
+					  unsigned int issue_flags)
+{
+	return -EOPNOTSUPP;
+}
 static inline int io_buffer_unregister(struct io_uring_cmd *cmd,
 				       unsigned int index,
 				       unsigned int issue_flags)
diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index 5384fbbf684e..4aada6548ac5 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -1006,6 +1006,41 @@ int io_buffer_register_request(struct io_uring_cmd *cmd, struct request *rq,
 }
 EXPORT_SYMBOL_GPL(io_buffer_register_request);
 
+/*
+ * bvs is copied internally. caller may free it on return.
+ */
+int io_buffer_register_bvec(struct io_uring_cmd *cmd, const struct bio_vec *bvs,
+			    unsigned int nr_bvecs, void (*release)(void *),
+			    void *priv, u8 dir, unsigned int index,
+			    unsigned int issue_flags)
+{
+	struct io_ring_ctx *ctx = cmd_to_io_kiocb(cmd)->ctx;
+	struct io_mapped_ubuf *imu;
+	struct bio_vec *bvec;
+	unsigned int i, total_bytes = 0;
+	int ret = 0;
+
+	for (i = 0; i < nr_bvecs; i++)
+		total_bytes += bvs[i].bv_len;
+
+	io_ring_submit_lock(ctx, issue_flags);
+	imu = io_kernel_buffer_init(ctx, nr_bvecs, total_bytes, dir, release,
+				    priv, index);
+	if (IS_ERR(imu)) {
+		ret = PTR_ERR(imu);
+		goto unlock;
+	}
+
+	bvec = imu->bvec;
+	for (i = 0; i < nr_bvecs; i++)
+		bvec[i] = bvs[i];
+
+unlock:
+	io_ring_submit_unlock(ctx, issue_flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(io_buffer_register_bvec);
+
 int io_buffer_unregister(struct io_uring_cmd *cmd, unsigned int index,
 			 unsigned int issue_flags)
 {
-- 
2.52.0

[PATCH v5 4/4] io_uring/rsrc: rename and export IO_IMU_DEST / IO_IMU_SOURCE

[Joanne Koong]

Rename IO_IMU_DEST and IO_IMU_SOURCE to IO_BUF_DEST and IO_BUF_SOURCE
and export it so subsystems may use it.

This is needed by the io_buffer_register_bvec() path for callers who may
need the buffer to be both readable and writable.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
---
 include/linux/io_uring_types.h | 5 +++++
 io_uring/io_uring.c            | 2 +-
 io_uring/rsrc.c                | 2 +-
 io_uring/rsrc.h                | 5 -----
 4 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
index 28e5dbdac55b..b4f0e69633ab 100644
--- a/include/linux/io_uring_types.h
+++ b/include/linux/io_uring_types.h
@@ -44,6 +44,11 @@ enum io_uring_cmd_flags {
 	IO_URING_F_COMPAT		= (1 << 12),
 };
 
+enum {
+	IO_BUF_DEST	= 1 << ITER_DEST,
+	IO_BUF_SOURCE	= 1 << ITER_SOURCE,
+};
+
 struct iou_loop_params;
 
 struct io_wq_work_node {
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 16122f877aed..b5debc615657 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -3215,7 +3215,7 @@ static int __init io_uring_init(void)
 	io_uring_optable_init();
 
 	/* imu->dir is u8 */
-	BUILD_BUG_ON((IO_IMU_DEST | IO_IMU_SOURCE) > U8_MAX);
+	BUILD_BUG_ON((IO_BUF_DEST | IO_BUF_SOURCE) > U8_MAX);
 
 	/*
 	 * Allow user copy in the per-command field, which starts after the
diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index 4aada6548ac5..7d9d155a85b1 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -820,7 +820,7 @@ static struct io_rsrc_node *io_sqe_buffer_register(struct io_ring_ctx *ctx,
 	imu->release = io_release_ubuf;
 	imu->priv = imu;
 	imu->flags = 0;
-	imu->dir = IO_IMU_DEST | IO_IMU_SOURCE;
+	imu->dir = IO_BUF_DEST | IO_BUF_SOURCE;
 	if (coalesced)
 		imu->folio_shift = data.folio_shift;
 	refcount_set(&imu->refs, 1);
diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h
index cff0f8834c35..8d48195faf9d 100644
--- a/io_uring/rsrc.h
+++ b/io_uring/rsrc.h
@@ -23,11 +23,6 @@ struct io_rsrc_node {
 	};
 };
 
-enum {
-	IO_IMU_DEST	= 1 << ITER_DEST,
-	IO_IMU_SOURCE	= 1 << ITER_SOURCE,
-};
-
 enum {
 	IO_REGBUF_F_KBUF		= 1,
 };
-- 
2.52.0

Re: [PATCH v5 0/4] io_uring: extend bvec registration

[Jens Axboe]

On 4/2/26 10:09 AM, Joanne Koong wrote:
> This series refactors and extends the io_uring registered buffers
> infrastructure to allow external subsystems to register pre-existing bvec
> arrays directly.
> 
> The motivation for the patches in this series is to make fuse zero-copy
> possible. These patches are split out from a previous larger
> fuse-over-io_uring series [1]. The fuse zero-copy work that builds on top of
> this is in [2].
> 
> Thanks,
> Joanne
> 
> [1] https://lore.kernel.org/linux-fsdevel/20260116233044.1532965-1-joannelkoong@gmail.com/
> [2] https://lore.kernel.org/linux-fsdevel/20260324224532.3733468-9-joannelkoong@gmail.com/
> 
> Changelog:
> v4: https://lore.kernel.org/io-uring/20260327172631.3380702-1-joannelkoong@gmail.com/
> v4 -> v5:
> * rebase to origin/for-7.1/io_uring 
> * drop the io_uring_registered_mem_region_get() patch

Series looks good to me, but I don't think you used the right base? It
does not seem to apply to for-7.1/io_uring, patch 1 runs into issues on
the ublk part.

Since this touches both and applies to neither right now, maybe do a
respin and just base it on my for-next. Then I'll setup a
for-7.1/io_uring-fuse branch that is just for-7.1/io_uring and
for-7.1/block merged together.

-- 
Jens Axboe

Re: [PATCH v5 0/4] io_uring: extend bvec registration

[Joanne Koong]

On Fri, Apr 3, 2026 at 9:21 AM Jens Axboe <axboe@kernel.dk> wrote:
>
> On 4/2/26 10:09 AM, Joanne Koong wrote:
> > This series refactors and extends the io_uring registered buffers
> > infrastructure to allow external subsystems to register pre-existing bvec
> > arrays directly.
> >
> > The motivation for the patches in this series is to make fuse zero-copy
> > possible. These patches are split out from a previous larger
> > fuse-over-io_uring series [1]. The fuse zero-copy work that builds on top of
> > this is in [2].
> >
> > Thanks,
> > Joanne
> >
> > [1] https://lore.kernel.org/linux-fsdevel/20260116233044.1532965-1-joannelkoong@gmail.com/
> > [2] https://lore.kernel.org/linux-fsdevel/20260324224532.3733468-9-joannelkoong@gmail.com/
> >
> > Changelog:
> > v4: https://lore.kernel.org/io-uring/20260327172631.3380702-1-joannelkoong@gmail.com/
> > v4 -> v5:
> > * rebase to origin/for-7.1/io_uring
> > * drop the io_uring_registered_mem_region_get() patch
>
> Series looks good to me, but I don't think you used the right base? It
> does not seem to apply to for-7.1/io_uring, patch 1 runs into issues on
> the ublk part.
>
> Since this touches both and applies to neither right now, maybe do a
> respin and just base it on my for-next. Then I'll setup a
> for-7.1/io_uring-fuse branch that is just for-7.1/io_uring and
> for-7.1/block merged together.

Ahh that's weird, it applies cleanly to for-7.1/io_uring on my end (on
top of commit f847bf6d2930) but I do see some merge conflicts with
for-next for the ublk commit 24d4c90286b9.

I'll rebase this to for-next and send that out.

Thanks,
Joanne


>
> --
> Jens Axboe

Re: [PATCH v5 0/4] io_uring: extend bvec registration

[Jens Axboe]

On 4/3/26 11:30 AM, Joanne Koong wrote:
> On Fri, Apr 3, 2026 at 9:21 AM Jens Axboe <axboe@kernel.dk> wrote:
>>
>> On 4/2/26 10:09 AM, Joanne Koong wrote:
>>> This series refactors and extends the io_uring registered buffers
>>> infrastructure to allow external subsystems to register pre-existing bvec
>>> arrays directly.
>>>
>>> The motivation for the patches in this series is to make fuse zero-copy
>>> possible. These patches are split out from a previous larger
>>> fuse-over-io_uring series [1]. The fuse zero-copy work that builds on top of
>>> this is in [2].
>>>
>>> Thanks,
>>> Joanne
>>>
>>> [1] https://lore.kernel.org/linux-fsdevel/20260116233044.1532965-1-joannelkoong@gmail.com/
>>> [2] https://lore.kernel.org/linux-fsdevel/20260324224532.3733468-9-joannelkoong@gmail.com/
>>>
>>> Changelog:
>>> v4: https://lore.kernel.org/io-uring/20260327172631.3380702-1-joannelkoong@gmail.com/
>>> v4 -> v5:
>>> * rebase to origin/for-7.1/io_uring
>>> * drop the io_uring_registered_mem_region_get() patch
>>
>> Series looks good to me, but I don't think you used the right base? It
>> does not seem to apply to for-7.1/io_uring, patch 1 runs into issues on
>> the ublk part.
>>
>> Since this touches both and applies to neither right now, maybe do a
>> respin and just base it on my for-next. Then I'll setup a
>> for-7.1/io_uring-fuse branch that is just for-7.1/io_uring and
>> for-7.1/block merged together.
> 
> Ahh that's weird, it applies cleanly to for-7.1/io_uring on my end (on
> top of commit f847bf6d2930) but I do see some merge conflicts with
> for-next for the ublk commit 24d4c90286b9.

Right, sorry I wasn't clear, does apply to for-7.1/io_uring, but you
end up with non-trivial merge conflicts. It's always a bit tricky as
the ublk changes generally take the block route, not the io_uring
route, as it's more closely tied to that side.

> I'll rebase this to for-next and send that out.

Thanks!

-- 
Jens Axboe