io_uring: rsrc: delegate VMA file-backed check to GUP

Now that the GUP explicitly checks FOLL_LONGTERM pin_user_pages() for
broken file-backed mappings in "mm/gup: disallow FOLL_LONGTERM GUP-nonfast
writing to file-backed mappings", there is no need to explicitly check VMAs
for this condition, so simply remove this logic from io_uring altogether.

Link: https://lkml.kernel.org/r/e4a4efbda9cd12df71e0ed81796dc630231a1ef2.1684350871.git.lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Sean Christopherson <seanjc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index d46f72a..b6451f8 100644 (file)
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -1030,9 +1030,8 @@ static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
 struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages)
 {
        unsigned long start, end, nr_pages;
-       struct vm_area_struct **vmas = NULL;
        struct page **pages = NULL;
-       int i, pret, ret = -ENOMEM;
+       int pret, ret = -ENOMEM;
 
        end = (ubuf + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
        start = ubuf >> PAGE_SHIFT;
@@ -1042,45 +1041,24 @@ struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages)
        if (!pages)
                goto done;
 
-       vmas = kvmalloc_array(nr_pages, sizeof(struct vm_area_struct *),
-                             GFP_KERNEL);
-       if (!vmas)
-               goto done;
-
        ret = 0;
        mmap_read_lock(current->mm);
        pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
-                             pages, vmas);
-       if (pret == nr_pages) {
-               /* don't support file backed memory */
-               for (i = 0; i < nr_pages; i++) {
-                       struct vm_area_struct *vma = vmas[i];
-
-                       if (vma_is_shmem(vma))
-                               continue;
-                       if (vma->vm_file &&
-                           !is_file_hugepages(vma->vm_file)) {
-                               ret = -EOPNOTSUPP;
-                               break;
-                       }
-               }
+                             pages, NULL);
+       if (pret == nr_pages)
                *npages = nr_pages;
-       } else {
+       else
                ret = pret < 0 ? pret : -EFAULT;
-       }
+
        mmap_read_unlock(current->mm);
        if (ret) {
-               /*
-                * if we did partial map, or found file backed vmas,
-                * release any pages we did get
-                */
+               /* if we did partial map, release any pages we did get */
                if (pret > 0)
                        unpin_user_pages(pages, pret);
                goto done;
        }
        ret = 0;
 done:
-       kvfree(vmas);
        if (ret < 0) {
                kvfree(pages);
                pages = ERR_PTR(ret);