[Xen-devel] [PATCH 19/34] fsl_hypervisor: convert put_page() to put_user_page*()

[john.hubbard@xxxxxxxxx]

From: John Hubbard <jhubbard@xxxxxxxxxx>

For pages that were retained via get_user_pages*(), release those pages
via the new put_user_page*() routines, instead of via put_page() or
release_pages().

This is part a tree-wide conversion, as described in commit fc1d8e7cca2d
("mm: introduce put_user_page*(), placeholder versions").

This changes the release code slightly, because each page slot in the
page_list[] array is no longer checked for NULL. However, that check
was wrong anyway, because the get_user_pages() pattern of usage here
never allowed for NULL entries within a range of pinned pages.

Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Rob Herring <robh@xxxxxxxxxx>
Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>
---
 drivers/virt/fsl_hypervisor.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/virt/fsl_hypervisor.c b/drivers/virt/fsl_hypervisor.c
index 93d5bebf9572..a8f78d572c45 100644
--- a/drivers/virt/fsl_hypervisor.c
+++ b/drivers/virt/fsl_hypervisor.c
@@ -292,11 +292,8 @@ static long ioctl_memcpy(struct fsl_hv_ioctl_memcpy __user 
*p)
                virt_to_phys(sg_list), num_pages);
 
 exit:
-       if (pages) {
-               for (i = 0; i < num_pages; i++)
-                       if (pages[i])
-                               put_page(pages[i]);
-       }
+       if (pages)
+               put_user_pages(pages, num_pages);
 
        kfree(sg_list_unaligned);
        kfree(pages);
-- 
2.22.0


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