Messages in this thread | | | Date | Tue, 6 Apr 2010 14:24:05 +0800 | Subject | Re: [PATCH] /dev/mem: Allow rewinding | From | Américo Wang <> |
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On Tue, Apr 6, 2010 at 1:43 PM, Wu Fengguang <fengguang.wu@intel.com> wrote: > On Tue, Apr 06, 2010 at 01:30:29PM +0800, Américo Wang wrote: >> On Tue, Apr 6, 2010 at 5:19 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote: >> > Le lundi 05 avril 2010 à 23:04 +0200, Eric Dumazet a écrit : >> >> Andrew, commit dcefafb6ac90ece8d68a6c203105f3d313e52da4 seems to be the >> >> problem. >> >> >> >> It breaks rewinds (negative offsets to lseek (... SEEK_CUR)) >> >> >> > >> > Here is a patch to make rewind working again on /dev/mem >> > >> > [PATCH] /dev/mem: Allow rewinding >> > >> > commit dcefafb6 (/dev/mem: dont allow seek to last page) >> > inadvertently disabled rewinding on /dev/mem. >> > >> > This broke x86info for example. >> > >> > Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> >> > --- >> > diff --git a/drivers/char/mem.c b/drivers/char/mem.c >> > index 1f3215a..3973a1d 100644 >> > --- a/drivers/char/mem.c >> > +++ b/drivers/char/mem.c >> > @@ -710,11 +710,6 @@ static loff_t memory_lseek(struct file *file, loff_t offset, int orig) >> > switch (orig) { >> > case SEEK_CUR: >> > offset += file->f_pos; >> > - if ((unsigned long long)offset < >> > - (unsigned long long)file->f_pos) { >> > - ret = -EOVERFLOW; >> > - break; >> > - } >> >> Why completely dropping the overflow check? What you need to do is just >> adding the 'offset < 0' case check. > > It will fall through to the next EOVERFLOW check in the SEEK_SET case :) >
Oh, right, I didn't read the code, merely the patch.
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