[PATCH for-next 11/12] io_uring: read_fixed retarget_rsrc support

[Dylan Yudaken <dylany@meta.com>]

Add can_retarget_rsrc handler for read_fixed

Signed-off-by: Dylan Yudaken <dylany@meta.com>
---
 io_uring/opdef.c |  1 +
 io_uring/rw.c    | 15 +++++++++++++++
 io_uring/rw.h    |  1 +
 3 files changed, 17 insertions(+)

diff --git a/io_uring/opdef.c b/io_uring/opdef.c
index 0018fe39cbb5..5159b3abc2b2 100644
--- a/io_uring/opdef.c
+++ b/io_uring/opdef.c
@@ -109,6 +109,7 @@ const struct io_op_def io_op_defs[] = {
 		.prep			= io_prep_rw,
 		.issue			= io_read,
 		.fail			= io_rw_fail,
+		.can_retarget_rsrc	= io_read_fixed_can_retarget_rsrc,
 	},
 	[IORING_OP_WRITE_FIXED] = {
 		.needs_file		= 1,
diff --git a/io_uring/rw.c b/io_uring/rw.c
index 7618e402dcec..d82fbe074bd9 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -1082,3 +1082,18 @@ bool io_read_can_retarget_rsrc(struct io_kiocb *req)
 
 	return true;
 }
+
+bool io_read_fixed_can_retarget_rsrc(struct io_kiocb *req)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+	u16 index;
+
+	if (unlikely(req->buf_index >= ctx->nr_user_bufs))
+		return false;
+
+	index = array_index_nospec(req->buf_index, ctx->nr_user_bufs);
+	if (ctx->user_bufs[index] != req->imu)
+		return false;
+
+	return io_read_can_retarget_rsrc(req);
+}
diff --git a/io_uring/rw.h b/io_uring/rw.h
index 715e7249463b..69cbc36560f6 100644
--- a/io_uring/rw.h
+++ b/io_uring/rw.h
@@ -23,3 +23,4 @@ int io_writev_prep_async(struct io_kiocb *req);
 void io_readv_writev_cleanup(struct io_kiocb *req);
 void io_rw_fail(struct io_kiocb *req);
 bool io_read_can_retarget_rsrc(struct io_kiocb *req);
+bool io_read_fixed_can_retarget_rsrc(struct io_kiocb *req);
-- 
2.30.2