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UPSTREAM: binder: Use memset_page() in binder_alloc_clear_buf()

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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_clear_buf() 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() but, instead of open
coding these two functions and adding a memset() of the virtual address
of the mapping, prefer memset_page().

Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Link: https://lore.kernel.org/r/20220425175754.8180-2-fmdefrancesco@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Bug: 368205746
Bug: 365876437
(cherry picked from commit 26eff2d66a)
Change-Id: I7bc041db662ee1e8758c173861b2229d6ad8eb1e
Signed-off-by: yenchia.chen <yenchia.chen@mediatek.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
This commit is contained in:
Fabio M. De Francesco
2022-04-25 19:57:52 +02:00
committed by Dongjin Kim
parent e38087f053
commit b5108d86fa
1 changed files with 1 additions and 4 deletions
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5
drivers/android/binder_alloc.c
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@@ -765,14 +765,11 @@ static void binder_alloc_clear_buf(struct binder_alloc *alloc,
unsigned long size;
struct page *page;
pgoff_t pgoff;
void *kptr;
page = binder_alloc_get_page(alloc, buffer,
buffer_offset, &pgoff);
size = min_t(size_t, bytes, PAGE_SIZE - pgoff);
kptr = kmap(page) + pgoff;
memset(kptr, 0, size);
kunmap(page);
memset_page(page, pgoff, 0, size);
bytes -= size;
buffer_offset += size;
}