Messages in this thread | | | Date | Thu, 24 Apr 2003 02:02:15 +0200 (MET DST) | From | Bartlomiej Zolnierkiewicz <> | Subject | Re: [PATCH] 2.5.67-ac2 direct-IO for IDE taskfile ioctl (0/4) |
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On Wed, 23 Apr 2003, Andrew Morton wrote:
> Andries Brouwer <aebr@win.tue.nl> wrote: > > > > On Wed, Apr 23, 2003 at 03:35:00PM -0700, Andrew Morton wrote: > > > > > What is special about the IDE ioctl approach? > > > > Usually one wants to use the standard commands for I/O. > > But if the purpose is to talk to the drive (set password, > > set native max, eject, change ZIP drive from big floppy > > mode to removable disk mode, etc. etc.) then one needs > > a means to execute IDE commands "by hand". > > Yes, but none of these are performance-critical and they don't involve > large amnounts of data. A copy is OK.
low-level benchmarking is somehow performance critical :-)
note that direct-IO here is _only_ bonus, main goal is to use the same code for _all_ ioctl and fs generated IDE IO (remember that all fs IDE IO is rq->bio based)
and this is work-in-progress...
> If all the rework against bio_map_user() and friends is needed for other > reasons then fine. But it doesn't seem to be needed for the IDE taskfile > ioctl.
Rework of bio_map_user() and co. is minimal and not needed but otherwise I will have to duplicate same code in 4 places. bio_map_user() now does allocated bio checking and grabs extra reference to bio which all users of old bio_map_user() have to do anyway (and they will probably forgot to).
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