Douglas Gilbert <[email protected]> wrote:
> Jens Axboe wrote:
> > On Fri, Feb 16 2007, Alan Stern wrote:
> >> From: James Bottomley <[email protected]>
> >>
> >> This patch (as854) separates out the two queue-oriented ioctls from
> >> the rest of the block-layer ioctls. The idea is that they should
> >> apply to any driver using a request_queue, even if the driver doesn't
> >> implement a block-device interface. The prototypical example is the
> >> sg driver, to which the patch adds the new interface.
> >>
> >> This will make it possible for cdrecord and related programs to
> >> retrieve reliably the max_sectors value, regardless of whether the
> >> user points it to an sr or an sg device. In particular, this will
> >> resolve Bugzilla entry #7026.
> >
> > The block bits are fine with me, the sg calling point is a bit of a sore
> > thumb (a char driver calling into block layer ioctls) though. So the
> > block layer bits are certainly ok with me, if Doug acks the sg bit I'll
> > merge everything up.
> >
> > (patch left below)
>
> Does this need to be in the sg driver?
>
> What is the hardware sector size of a SES or OSD device?
>
> As for the max_sector variable, wouldn't it be better
> to generate a new ioctl that yielded the limit in bytes?
> Making a driver variable that implicitly assumes sectors
> are 512 bytes in length more visible to the user space
> seems like a step in the wrong direction.
This is what I did propose. I know of no SCSI device made since 1986 that
has a "hardware sector size". This is really a DMA size limit in bytes
and if you return the number in an unrelated multiple of a fraction, you
will not be able to use the optmium max transfer size.
> Alternatively the SG_GET_RESERVED_SIZE ioctl could be
> modified to yield no more than max_sectors*512 .
This is what I did propose 3 months ago and already 2 years ago.
Jörg
--
EMail:[email protected] (home) Jörg Schilling D-13353 Berlin
[email protected] (uni)
[email protected] (work) Blog: http://schily.blogspot.com/
URL: http://cdrecord.berlios.de/old/private/ ftp://ftp.berlios.de/pub/schily
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
