[PATCH v2 1/5] io_uring/rsrc: rename and export io_lock_two_rings()

[David Wei <dw@davidwei.uk>]

Rename lock_two_rings() to io_lock_two_rings() and export. This will be
used when registering a src ifq owned by one ring as a proxy in another
ring. During this process both rings need to be locked in a
deterministic order, similar to the current user io_clone_buffers().

Signed-off-by: David Wei <dw@davidwei.uk>
---
 io_uring/rsrc.c | 4 ++--
 io_uring/rsrc.h | 1 +
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index d787c16dc1c3..d245b7592eee 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -1148,7 +1148,7 @@ int io_import_reg_buf(struct io_kiocb *req, struct iov_iter *iter,
 }
 
 /* Lock two rings at once. The rings must be different! */
-static void lock_two_rings(struct io_ring_ctx *ctx1, struct io_ring_ctx *ctx2)
+void io_lock_two_rings(struct io_ring_ctx *ctx1, struct io_ring_ctx *ctx2)
 {
 	if (ctx1 > ctx2)
 		swap(ctx1, ctx2);
@@ -1299,7 +1299,7 @@ int io_register_clone_buffers(struct io_ring_ctx *ctx, void __user *arg)
 	src_ctx = file->private_data;
 	if (src_ctx != ctx) {
 		mutex_unlock(&ctx->uring_lock);
-		lock_two_rings(ctx, src_ctx);
+		io_lock_two_rings(ctx, src_ctx);
 
 		if (src_ctx->submitter_task &&
 		    src_ctx->submitter_task != current) {
diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h
index a3ca6ba66596..b002c4a5a8cd 100644
--- a/io_uring/rsrc.h
+++ b/io_uring/rsrc.h
@@ -70,6 +70,7 @@ int io_import_reg_vec(int ddir, struct iov_iter *iter,
 int io_prep_reg_iovec(struct io_kiocb *req, struct iou_vec *iv,
 			const struct iovec __user *uvec, size_t uvec_segs);
 
+void io_lock_two_rings(struct io_ring_ctx *ctx1, struct io_ring_ctx *ctx2);
 int io_register_clone_buffers(struct io_ring_ctx *ctx, void __user *arg);
 int io_sqe_buffers_unregister(struct io_ring_ctx *ctx);
 int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
-- 
2.47.3