io_uring: modularize io_sqe_buffers_register

Move allocation of buffer management structures, and validation of
buffers into separate routines.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index ec70ba0..4cdf0f9 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8579,13 +8579,8 @@ done:
        return ret;
 }
 
-static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
-                                  unsigned int nr_args)
+static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args)
 {
-       int i, ret;
-       struct iovec iov;
-       struct page *last_hpage = NULL;
-
        if (ctx->user_bufs)
                return -EBUSY;
        if (!nr_args || nr_args > UIO_MAXIOV)
@@ -8596,6 +8591,37 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
        if (!ctx->user_bufs)
                return -ENOMEM;
 
+       return 0;
+}
+
+static int io_buffer_validate(struct iovec *iov)
+{
+       /*
+        * Don't impose further limits on the size and buffer
+        * constraints here, we'll -EINVAL later when IO is
+        * submitted if they are wrong.
+        */
+       if (!iov->iov_base || !iov->iov_len)
+               return -EFAULT;
+
+       /* arbitrary limit, but we need something */
+       if (iov->iov_len > SZ_1G)
+               return -EFAULT;
+
+       return 0;
+}
+
+static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
+                                  unsigned int nr_args)
+{
+       int i, ret;
+       struct iovec iov;
+       struct page *last_hpage = NULL;
+
+       ret = io_buffers_map_alloc(ctx, nr_args);
+       if (ret)
+               return ret;
+
        for (i = 0; i < nr_args; i++) {
                struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
 
@@ -8603,17 +8629,8 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
                if (ret)
                        break;
 
-               /*
-                * Don't impose further limits on the size and buffer
-                * constraints here, we'll -EINVAL later when IO is
-                * submitted if they are wrong.
-                */
-               ret = -EFAULT;
-               if (!iov.iov_base || !iov.iov_len)
-                       break;
-
-               /* arbitrary limit, but we need something */
-               if (iov.iov_len > SZ_1G)
+               ret = io_buffer_validate(&iov);
+               if (ret)
                        break;
 
                ret = io_sqe_buffer_register(ctx, &iov, imu, &last_hpage);