io_uring: add buffer unmap helper

Add a helper for unmapping registered buffers, better than double
indexing and will be reused in the future.

Suggested-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/66cbc6ea863be865bac7b7080ed6a3d5c542b71f.1618101759.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 1eb815660fe84bd1572e297e460df79ae2cfcb91..e9a2f8f39eb32c3ec63bce820288ff3aadae8e65 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8093,25 +8093,27 @@ static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries,
        return off;
 }
 
+static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf *imu)
+{
+       unsigned int i;
+
+       for (i = 0; i < imu->nr_bvecs; i++)
+               unpin_user_page(imu->bvec[i].bv_page);
+       if (imu->acct_pages)
+               io_unaccount_mem(ctx, imu->acct_pages);
+       kvfree(imu->bvec);
+       imu->nr_bvecs = 0;
+}
+
 static int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
 {
-       int i, j;
+       unsigned int i;
 
        if (!ctx->user_bufs)
                return -ENXIO;
 
-       for (i = 0; i < ctx->nr_user_bufs; i++) {
-               struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
-
-               for (j = 0; j < imu->nr_bvecs; j++)
-                       unpin_user_page(imu->bvec[j].bv_page);
-
-               if (imu->acct_pages)
-                       io_unaccount_mem(ctx, imu->acct_pages);
-               kvfree(imu->bvec);
-               imu->nr_bvecs = 0;
-       }
-
+       for (i = 0; i < ctx->nr_user_bufs; i++)
+               io_buffer_unmap(ctx, &ctx->user_bufs[i]);
        kfree(ctx->user_bufs);
        ctx->user_bufs = NULL;
        ctx->nr_user_bufs = 0;