Messages in this thread | | | Date | Mon, 18 Jan 2010 10:49:13 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [PATCH 6/6] vfs: introduce FMODE_NEG_OFFSET for allowing negative f_pos |
| |
On Mon, 18 Jan 2010 10:32:49 +0900 OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> wrote:
> OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> writes: > > >>> Um... How do lseek() work? It sounds like to violate error code range. > >> > >> This is for read-write. As far as I know, > >> - generic_file_llseek, > >> - default_llseek > >> - no_llseek > >> > >> doesn't call this function. > > > > It seems to allow to set negative value to ->f_pos, right? So, lseek() > > returns (uses) it? > > BTW, another concern by negative "pos" value is, the following like code > > pos >> shift_bits > > it will break the above. So, I think it should be checked if not yet.
Where do we check ?
FMODE_NEG_OFFSET is just used by /dev/mem and /proc/<pid>/mem. And I don't think there are no additonal users. So, I myself don't have has such concerns...
Thanks, -Kame
| |