io_uring: shut io_prep_async_work warning

[platform/kernel/linux-starfive.git] / io_uring / kbuf.c

diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c
index cd1d9dd..79c2545 100644 (file)
--- a/io_uring/kbuf.c
+++ b/io_uring/kbuf.c
@@ -491,6 +491,24 @@ static int io_pin_pbuf_ring(struct io_uring_buf_reg *reg,
                return PTR_ERR(pages);
 
        br = page_address(pages[0]);
+#ifdef SHM_COLOUR
+       /*
+        * On platforms that have specific aliasing requirements, SHM_COLOUR
+        * is set and we must guarantee that the kernel and user side align
+        * nicely. We cannot do that if IOU_PBUF_RING_MMAP isn't set and
+        * the application mmap's the provided ring buffer. Fail the request
+        * if we, by chance, don't end up with aligned addresses. The app
+        * should use IOU_PBUF_RING_MMAP instead, and liburing will handle
+        * this transparently.
+        */
+       if ((reg->ring_addr | (unsigned long) br) & (SHM_COLOUR - 1)) {
+               int i;
+
+               for (i = 0; i < nr_pages; i++)
+                       unpin_user_page(pages[i]);
+               return -EINVAL;
+       }
+#endif
        bl->buf_pages = pages;
        bl->buf_nr_pages = nr_pages;
        bl->buf_ring = br;