From: Ira Weiny <ira.weiny@xxxxxxxxx> Subject: iov_iter: lift memzero_page() to highmem.h Patch series "btrfs: Convert kmap/memset/kunmap to memzero_user()". Lifting memzero_user(), convert it to kmap_local_page() and then use it in btrfs. This patch (of 3): memzero_page() can replace the kmap/memset/kunmap pattern in other places in the code. While zero_user() has the same interface it is not the same call and its use should be limited and some of those calls may be better converted from zero_user() to memzero_page().[1] But that is not addressed in this series. Lift memzero_page() to highmem. [1] https://lore.kernel.org/lkml/CAHk-=wijdojzo56FzYqE5TOYw2Vws7ik3LEMGj9SPQaJJ+Z73Q@xxxxxxxxxxxxxx/ Link: https://lkml.kernel.org/r/20210309212137.2610186-1-ira.weiny@xxxxxxxxx Link: https://lkml.kernel.org/r/20210309212137.2610186-2-ira.weiny@xxxxxxxxx Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx> Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: David Sterba <dsterba@xxxxxxxx> Cc: Chris Mason <clm@xxxxxx> Cc: Josef Bacik <josef@xxxxxxxxxxxxxx> Cc: Chaitanya Kulkarni <chaitanya.kulkarni@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/highmem.h | 7 +++++++ lib/iov_iter.c | 8 +------- 2 files changed, 8 insertions(+), 7 deletions(-) --- a/include/linux/highmem.h~iov_iter-lift-memzero_page-to-highmemh +++ a/include/linux/highmem.h @@ -332,4 +332,11 @@ static inline void memcpy_to_page(struct kunmap_local(to); } +static inline void memzero_page(struct page *page, size_t offset, size_t len) +{ + char *addr = kmap_atomic(page); + memset(addr + offset, 0, len); + kunmap_atomic(addr); +} + #endif /* _LINUX_HIGHMEM_H */ --- a/lib/iov_iter.c~iov_iter-lift-memzero_page-to-highmemh +++ a/lib/iov_iter.c @@ -5,6 +5,7 @@ #include <linux/fault-inject-usercopy.h> #include <linux/uio.h> #include <linux/pagemap.h> +#include <linux/highmem.h> #include <linux/slab.h> #include <linux/vmalloc.h> #include <linux/splice.h> @@ -507,13 +508,6 @@ void iov_iter_init(struct iov_iter *i, u } EXPORT_SYMBOL(iov_iter_init); -static void memzero_page(struct page *page, size_t offset, size_t len) -{ - char *addr = kmap_atomic(page); - memset(addr + offset, 0, len); - kunmap_atomic(addr); -} - static inline bool allocated(struct pipe_buffer *buf) { return buf->ops == &default_pipe_buf_ops; _
