[PATCH V3 02/12] io_uring: refactor io_prep_reg_iovec() for BPF kfunc use

[Ming Lei <ming.lei@redhat.com>]

Split io_prep_reg_iovec() into:
- __io_prep_reg_iovec(): core logic without request association
- io_prep_reg_iovec(): inline wrapper handling request flags

The core function takes explicit 'compat' and 'need_clean' parameters
instead of accessing req directly. This allows BPF kfuncs to prepare
vectored buffers without request association, enabling support for
multiple buffers per request.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 io_uring/rsrc.c | 11 +++++------
 io_uring/rsrc.h | 21 +++++++++++++++++++--
 2 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index d65d3b4149f8..0b3e4cb5e879 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -1517,8 +1517,8 @@ int io_import_reg_vec(int ddir, struct iov_iter *iter,
 	return io_vec_fill_bvec(ddir, iter, imu, iov, nr_iovs, vec);
 }
 
-int io_prep_reg_iovec(struct io_kiocb *req, struct iou_vec *iv,
-		      const struct iovec __user *uvec, size_t uvec_segs)
+int __io_prep_reg_iovec(struct iou_vec *iv, const struct iovec __user *uvec,
+			size_t uvec_segs, bool compat, bool *need_clean)
 {
 	struct iovec *iov;
 	int iovec_off, ret;
@@ -1528,17 +1528,16 @@ int io_prep_reg_iovec(struct io_kiocb *req, struct iou_vec *iv,
 		ret = io_vec_realloc(iv, uvec_segs);
 		if (ret)
 			return ret;
-		req->flags |= REQ_F_NEED_CLEANUP;
+		if (need_clean)
+			*need_clean = true;
 	}
 
 	/* pad iovec to the right */
 	iovec_off = iv->nr - uvec_segs;
 	iov = iv->iovec + iovec_off;
-	res = iovec_from_user(uvec, uvec_segs, uvec_segs, iov,
-			      io_is_compat(req->ctx));
+	res = iovec_from_user(uvec, uvec_segs, uvec_segs, iov, compat);
 	if (IS_ERR(res))
 		return PTR_ERR(res);
 
-	req->flags |= REQ_F_IMPORT_BUFFER;
 	return 0;
 }
diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h
index cc68cba919ab..c2c729a9f568 100644
--- a/io_uring/rsrc.h
+++ b/io_uring/rsrc.h
@@ -4,6 +4,7 @@
 
 #include <linux/io_uring_types.h>
 #include <linux/lockdep.h>
+#include "io_uring.h"
 
 #define IO_VEC_CACHE_SOFT_CAP		256
 
@@ -83,8 +84,24 @@ static inline int io_import_reg_buf(struct io_kiocb *req, struct iov_iter *iter,
 int io_import_reg_vec(int ddir, struct iov_iter *iter,
 			struct io_kiocb *req, struct iou_vec *vec,
 			unsigned nr_iovs, unsigned issue_flags);
-int io_prep_reg_iovec(struct io_kiocb *req, struct iou_vec *iv,
-			const struct iovec __user *uvec, size_t uvec_segs);
+int __io_prep_reg_iovec(struct iou_vec *iv, const struct iovec __user *uvec,
+			size_t uvec_segs, bool compat, bool *need_clean);
+
+static inline int io_prep_reg_iovec(struct io_kiocb *req, struct iou_vec *iv,
+				    const struct iovec __user *uvec,
+				    size_t uvec_segs)
+{
+	bool need_clean = false;
+	int ret;
+
+	ret = __io_prep_reg_iovec(iv, uvec, uvec_segs,
+				  io_is_compat(req->ctx), &need_clean);
+	if (need_clean)
+		req->flags |= REQ_F_NEED_CLEANUP;
+	if (ret >= 0)
+		req->flags |= REQ_F_IMPORT_BUFFER;
+	return ret;
+}
 
 int io_register_clone_buffers(struct io_ring_ctx *ctx, void __user *arg);
 int io_sqe_buffers_unregister(struct io_ring_ctx *ctx);
-- 
2.53.0