On Fri, Oct 9, 2020 at 12:52 PM <ira.weiny@xxxxxxxxx> wrote:
>
> From: Ira Weiny <ira.weiny@xxxxxxxxx>
>
> The kmap() calls in this FS are localized to a single thread. To avoid
> the over head of global PKRS updates use the new kmap_thread() call.
>
> Cc: Nicolas Pitre <nico@xxxxxxxxxxx>
> Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
> ---
> fs/cramfs/inode.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c
> index 912308600d39..003c014a42ed 100644
> --- a/fs/cramfs/inode.c
> +++ b/fs/cramfs/inode.c
> @@ -247,8 +247,8 @@ static void *cramfs_blkdev_read(struct super_block *sb, unsigned int offset,
> struct page *page = pages[i];
>
> if (page) {
> - memcpy(data, kmap(page), PAGE_SIZE);
> - kunmap(page);
> + memcpy(data, kmap_thread(page), PAGE_SIZE);
> + kunmap_thread(page);
Why does this need a sleepable kmap? This looks like a textbook
kmap_atomic() use case.
