fix default_file_splice_read()

Botched calculation of number of pages.  As the result,
we were dropping pieces when doing splice to pipe from
e.g. 9p.

Reported-by: Alexei Starovoitov <[email protected]>
Tested-by: Alexei Starovoitov <[email protected]>
Signed-off-by: Al Viro <[email protected]>
This commit is contained in:
Al Viro 2016-11-26 20:05:42 -05:00
commit 8e54cadab4

View file

@ -408,7 +408,8 @@ static ssize_t default_file_splice_read(struct file *in, loff_t *ppos,
if (res <= 0)
return -ENOMEM;
nr_pages = res / PAGE_SIZE;
BUG_ON(dummy);
nr_pages = DIV_ROUND_UP(res, PAGE_SIZE);
vec = __vec;
if (nr_pages > PIPE_DEF_BUFFERS) {