3 files changed, 33 insertions, 0 deletions
diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c
index 72b6af1d2ed3b..18df5a9d2f5e7 100644
--- a/io_uring/kbuf.c
+++ b/io_uring/kbuf.c
@@ -750,6 +750,32 @@ int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
 	return 0;
 }
 
+int io_register_pbuf_status(struct io_ring_ctx *ctx, void __user *arg)
+{
+	struct io_uring_buf_status buf_status;
+	struct io_buffer_list *bl;
+	int i;
+
+	if (copy_from_user(&buf_status, arg, sizeof(buf_status)))
+		return -EFAULT;
+
+	for (i = 0; i < ARRAY_SIZE(buf_status.resv); i++)
+		if (buf_status.resv[i])
+			return -EINVAL;
+
+	bl = io_buffer_get_list(ctx, buf_status.buf_group);
+	if (!bl)
+		return -ENOENT;
+	if (!bl->is_mapped)
+		return -EINVAL;
+
+	buf_status.head = bl->head;
+	if (copy_to_user(arg, &buf_status, sizeof(buf_status)))
+		return -EFAULT;
+
+	return 0;
+}
+
 void *io_pbuf_get_address(struct io_ring_ctx *ctx, unsigned long bgid)
 {
 	struct io_buffer_list *bl;
diff --git a/io_uring/kbuf.h b/io_uring/kbuf.h
index 9be5960817ea1..53dfaa71a397c 100644
--- a/io_uring/kbuf.h
+++ b/io_uring/kbuf.h
@@ -53,6 +53,7 @@ int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags);
 
 int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg);
 int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg);
+int io_register_pbuf_status(struct io_ring_ctx *ctx, void __user *arg);
 
 void io_kbuf_mmap_list_free(struct io_ring_ctx *ctx);
 
diff --git a/io_uring/register.c b/io_uring/register.c
index a4286029e920c..708dd1d89add4 100644
--- a/io_uring/register.c
+++ b/io_uring/register.c
@@ -542,6 +542,12 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
 			break;
 		ret = io_register_file_alloc_range(ctx, arg);
 		break;
+	case IORING_REGISTER_PBUF_STATUS:
+		ret = -EINVAL;
+		if (!arg || nr_args != 1)
+			break;
+		ret = io_register_pbuf_status(ctx, arg);
+		break;
 	default:
 		ret = -EINVAL;
 		break;