lkml.org 
[lkml]   [2010]   [Oct]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH v2] procfs: fix numbering in /proc/locks
    On Tue, 05 Oct 2010 14:14:11 +0200
    Jerome Marchand <jmarchan@redhat.com> wrote:

    > On 09/30/2010 02:38 PM, Jerome Marchand wrote:
    > >
    > > The lock number in /proc/locks (first field) is implemented by a counter
    > > (private field of struct seq_file) which is incremented at each call of
    > > locks_show() and reset to 1 in locks_start() whatever the offset is. It
    > > should be reset according to the actual position in the list.
    > >
    > > Moreover, locks_show() can be called twice to print a single line thus
    > > skipping a number. The counter should be incremented in locks_next().
    > >
    > > Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
    > > ---
    > > locks.c | 4 ++--
    > > 1 file changed, 2 insertions(+), 2 deletions(-)
    > >
    > > diff --git a/fs/locks.c b/fs/locks.c
    > > index ab24d49..49d7343 100644
    > > --- a/fs/locks.c
    > > +++ b/fs/locks.c
    > > @@ -2166,19 +2166,19 @@ static int locks_show(struct seq_file *f, void *v)
    > > list_for_each_entry(bfl, &fl->fl_block, fl_block)
    > > lock_get_status(f, bfl, (long)f->private, " ->");
    > >
    > > - f->private++;
    > > return 0;
    > > }
    > >
    > > static void *locks_start(struct seq_file *f, loff_t *pos)
    > > {
    > > lock_kernel();
    > > - f->private = (void *)1;
    > > + f->private = (void *) (*pos + 1);
    >
    > That cast trigger a warning on some arch:
    > "warning: cast to pointer from integer of different size"
    >
    > There is no real risk here. At worst /proc/locks will show wrong number
    > if there is more than 2^32 locks, but should I mute the warning it with
    > something like:
    > f->private = (void *) (size_t) (*pos + 1);
    > ?

    Putting a loff_t into a void* is a pretty alarming thing to do. If
    we're really going to do that then use a (long) cast and put a very
    good comment at the code site explaining why the bug doesn't matter, so
    people aren't misled.

    But really, why sweat it? kmalloc the eight bytes, make ->private
    point at that and we never have to think about it again. Bonus points
    for doing this without any typecasts ;)



    \
     
     \ /
      Last update: 2010-10-08 01:31    [W:0.023 / U:29.976 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site