On Sun, 9 Nov 2008, Bartlomiej Zolnierkiewicz wrote: > On Saturday 18 October 2008, Bartlomiej Zolnierkiewicz wrote: > > On Saturday 18 October 2008, Geert Uytterhoeven wrote: > > > On Sat, 18 Oct 2008, Michael Schmitz wrote: > > > > > While working on ide_do_request() improvements I stumbled upon > > > > > mismatched ide_get_lock() / ide_release_lock() calls. > > > > > > > > > > [ It seems to be known issue: > > > > > http://marc.info/?l=linux-m68k&m=121423752829622&w=2 ] > > > > > > > > It is a known issue, and I submitted a simple fix to Geert a month or so ago. > > > > It involves moving the ide_get_lock call inside the request loop instead of > > > > doing it once at the start of the function. > > > > > > See http://marc.info/?l=linux-ide&m=121473433631934&w=2 > > > > > > In response to this patch, I wondered: > > > > > > > > If hwgroup->busy serves a similar purpose to falconide_intr_lock, what > > > > > about > > > > > moving the setting/clearing of hwgroup->busy into > > > > > ide_{get,release}_lock() > > > > > (and possibly renaming ide_{get,release}_lock() to e.g. > > > > > ide_hwgroup_{set,clear}_busy())? > > > > > > > > > > What about the other places where hwgroup->busy is set/cleared? > > > > > > And Michael responsed: > > > > > > > Uh - that's where it gets a bit sticky again. hwgroup->busy is set and > > > > cleared quite a lot 'preemptively' all over ide-io.c, f.e. in timeout > > > > handling. I'm not sure > > > > whether this would just reintroduce the bug message. > > > > > > > > The lock must be held as long as there are any interrupts to be expected > > > > from IDE. If the hwgroup->busy semantics reflects just that, it's worth > > > > a try. > > > > > > Bart, can you shed a light on the hwgroup->busy semantics? > > > > hwgroup->busy means that hwgroup is busy ;-) > > > > It protects against any access to the underlying hardware so it is > > also used when device is accessed in polling mode (without waiting > > for IRQ). However your proposal still sounds fine. We can treat > > hwgroup->busy as "waiting for IRQ" flag on Falcon and it would be > > correct (we will just hold the lock needlessly sometimes but we're > > already doing exactly that). > > > > [ The one thing that we have to watch out is not to leak IDE core > > specific things to <asm/ide.h> and host/platform specific ones to > > IDE core so some new abstraction level may be needed for handling > > ST-DMA lock itself (->[un]lock_host methods in struct ide_port_ops > > or something along the lines)... ] > > Since there was no follow-ups on this I've just applied Michael's > patch for now (& will push it to Linus for .28)... Thank you very much! Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
