On Fri, Dec 08, 2000 at 04:19:45PM -0800, Matthew Jacob wrote:
>
> > >
> > > On Fri, 8 Dec 2000, Alan Cox wrote:
> > >
> > > > > Yes, and I believe that this is what's broken about the SCSI midlayer. The
>the
> > > > > io_request_lock cannot be completely released in a SCSI HBA because the fla
> > You can drop it with spin_unlock_irq and that is fine. I do that with no
> > problems in the I2O scsi driver for example
>
> I am (like, I think I *finally* got locking sorta right in my QLogic driver),
> but doesn't this still leave ints blocked for this CPU at least?
spin_unlock_irq uncond
> >
> > On Fri, 8 Dec 2000, Alan Cox wrote:
> >
> > > > Yes, and I believe that this is what's broken about the SCSI midlayer. The the
> > > > io_request_lock cannot be completely released in a SCSI HBA because the flags
> > >
> > > You can drop it with spin_unlock_irq and that is fine. I do t
>
> I am actually concerned about the following case:
>
> The add_request ON CPU_1 function calls
> spin_lock_irqsave(&io_request_lock,flags);
>
> Our I/O Function unlocks the spinlock and goes to sleep.
>
> Finally, the add_request function, NOW ON CPU_2 calls
> spin_unlock
On Fri, Dec 08, 2000 at 04:03:58PM -0800, Matthew Jacob wrote:
>
>
> On Fri, 8 Dec 2000, Alan Cox wrote:
>
> > > Yes, and I believe that this is what's broken about the SCSI midlayer. The the
> > > io_request_lock cannot be completely released in a SCSI HBA because the flags
> >
> > You can dr
>
>
>
> On Fri, 8 Dec 2000, Alan Cox wrote:
>
> > > Yes, and I believe that this is what's broken about the SCSI midlayer. The the
> > > io_request_lock cannot be completely released in a SCSI HBA because the flags
> >
> > You can drop it with spin_unlock_irq and that is fine. I do that with
On Fri, 8 Dec 2000, Alan Cox wrote:
> > Yes, and I believe that this is what's broken about the SCSI midlayer. The the
> > io_request_lock cannot be completely released in a SCSI HBA because the flags
>
> You can drop it with spin_unlock_irq and that is fine. I do that with no
> problems in th
> Yes, and I believe that this is what's broken about the SCSI midlayer. The the
> io_request_lock cannot be completely released in a SCSI HBA because the flags
You can drop it with spin_unlock_irq and that is fine. I do that with no problems
in the I2O scsi driver for example
-
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> > spin_lock_irq(&io_request_lock);
> > we finish the request and return to the add_request function which calls
> > spin_unlock_irqrestore(&io_request_lock,flags);
> > and restores the flags.
> >
> > Isn't it possible now that the flags which we restore are out of date now?
> > I
> spin_lock_irq(&io_request_lock);
> we finish the request and return to the add_request function which calls
> spin_unlock_irqrestore(&io_request_lock,flags);
> and restores the flags.
>
> Isn't it possible now that the flags which we restore are out of date now?
> Is this idiom
>
> > I looked at the implementation of the nbd which just calls
> >
> > spin_unlock_irq(&io_request_lock);
> > ... do network io ...
> > spin_lock_irq(&io_request_lock);
> >
> > This seems to work but it looks very dangerous to me (and ugly, too). Isn't there
>a better way to do
> I looked at the implementation of the nbd which just calls
>
> spin_unlock_irq(&io_request_lock);
> ... do network io ...
> spin_lock_irq(&io_request_lock);
>
> This seems to work but it looks very dangerous to me (and ugly, too). Isn't there a
>better way to do this?
It i
Hi
I'm trying to write a block device driver which does some network stuff to satisfy the
requests. The problem is, that the network stuff wants to grab the io_request_lock
which does not work because this lock is already locked when I come into the
request_fn of my device.
I looked at the im
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