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Subject[PATCH v2 2/3] binder: Use kmap_local_page() in binder_alloc_copy_user_to_buffer()
Date
The use of kmap() is being deprecated in favor of kmap_local_page()
where it is feasible. With kmap_local_page(), the mapping is per
thread, CPU local and not globally visible.

binder_alloc_copy_user_to_buffer() is a function where the use of
kmap_local_page() in place of kmap() is correctly suited because
the mapping is local to the thread.

Therefore, use kmap_local_page() / kunmap_local().

Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
---

v1->v2: Add Todd Kjos's tag in the commit message (thanks!).

drivers/android/binder_alloc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index 0b3f2f569053..0875c463c002 100644
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -1217,9 +1217,9 @@ binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc,
page = binder_alloc_get_page(alloc, buffer,
buffer_offset, &pgoff);
size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
- kptr = kmap(page) + pgoff;
+ kptr = kmap_local_page(page) + pgoff;
ret = copy_from_user(kptr, from, size);
- kunmap(page);
+ kunmap_local(kptr);
if (ret)
return bytes - size + ret;
bytes -= size;
--
2.34.1
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