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authorChristian König <christian.koenig@amd.com>2020-09-14 15:09:33 +0200
committerChristian König <christian.koenig@amd.com>2020-11-19 10:36:36 +0100
commit295992fb815e791d14b18ef7cdbbaf1a76211a31 (patch)
tree2b72922a11a0abd63cb11969d3fd5cd7d2874e1c /mm/util.c
parent1527f926fd04490f648c42f42b45218a04754f87 (diff)
mm: introduce vma_set_file function v5
Add the new vma_set_file() function to allow changing vma->vm_file with the necessary refcount dance. v2: add more users of this. v3: add missing EXPORT_SYMBOL, rebase on mmap cleanup, add comments why we drop the reference on two occasions. v4: make it clear that changing an anonymous vma is illegal. v5: move vma_set_file to mm/util.c Signed-off-by: Christian König <christian.koenig@amd.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> (v2) Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Link: https://patchwork.freedesktop.org/patch/399360/
Diffstat (limited to 'mm/util.c')
-rw-r--r--mm/util.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/mm/util.c b/mm/util.c
index 4ddb6e186dd5..8c9b7d1e7c49 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -311,6 +311,18 @@ int vma_is_stack_for_current(struct vm_area_struct *vma)
return (vma->vm_start <= KSTK_ESP(t) && vma->vm_end >= KSTK_ESP(t));
}
+/*
+ * Change backing file, only valid to use during initial VMA setup.
+ */
+void vma_set_file(struct vm_area_struct *vma, struct file *file)
+{
+ /* Changing an anonymous vma with this is illegal */
+ get_file(file);
+ swap(vma->vm_file, file);
+ fput(file);
+}
+EXPORT_SYMBOL(vma_set_file);
+
#ifndef STACK_RND_MASK
#define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12)) /* 8MB of VA */
#endif