Revert "io_uring/rsrc: disallow multi-source reg buffers"

This reverts commit edd478269640b360c6f301f2baa04abdda563ef3.

There's really no specific need to disallow multiple sources of buffers,
and io_uring really should not be mandating this by itself. We should
be able to solely rely on GUP making these decisions.

As this also stands in the way of a cleanup where io_uring is the odd
one out, kill it.

Link: https://lore.kernel.org/all/61ded378-51a8-1dcb-b631-fda1903248a9@gmail.com/
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index 20dcc76..ddee7ad 100644 (file)
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -1053,17 +1053,14 @@ struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages)
        pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
                              pages, vmas);
        if (pret == nr_pages) {
-               struct file *file = vmas[0]->vm_file;
-
                /* don't support file backed memory */
                for (i = 0; i < nr_pages; i++) {
-                       if (vmas[i]->vm_file != file) {
-                               ret = -EINVAL;
-                               break;
-                       }
-                       if (!file)
+                       struct vm_area_struct *vma = vmas[i];
+
+                       if (vma_is_shmem(vma))
                                continue;
-                       if (!vma_is_shmem(vmas[i]) && !is_file_hugepages(file)) {
+                       if (vma->vm_file &&
+                           !is_file_hugepages(vma->vm_file)) {
                                ret = -EOPNOTSUPP;
                                break;
                        }