On Thursday, May 24, 2012, James Bottomley wrote:
> On Wed, 2012-05-23 at 19:22 -0700, Dan Williams wrote:
> > On Wed, 2012-05-23 at 23:56 +0100, James Bottomley wrote:
> > > On Wed, 2012-05-23 at 14:04 -0400, David Miller wrote:
> > > > From: Meelis Roos <mroos@xxxxxxxx>
> > > > Date: Wed, 23 May 2012 19:46:46 +0300 (EEST)
> > > >
> > > > CC:'ing interested parties.
> > > >
> > > > >> > Just tested 3.4.0-02580-g72c04af on about 10 machines. While most of
> > > > >> > them work (including 3 different sparc64 machines with real scsi disks),
> > > > >> > Sun Netra X1 with pata_ali and IDE disk consistently fails to boot. sda
> > > > >> > is recognized but no partitions. 3.3.0 works fine, as did something
> > > > >> > around 3.4-rc7 (plain 3.4 not tested yet). No other IDE machines tested
> > > > >> > yet since I have none with remote console at the moment.
> > > > >>
> > > > >> If 3.4.0-final is OK, start bisecting from v3.4.0 until 72c04af. One
> > > > >> possibility could be the sparc64 NOBOOTMEM conversion that went into
> > > > >> the merge window.
> > > > >
> > > > > Bisecting leads to this commit:
> > > > >
> > > > > a7a20d103994fd760766e6c9d494daa569cbfe06 is the first bad commit
> > > > > commit a7a20d103994fd760766e6c9d494daa569cbfe06
> > > > > Author: Dan Williams <dan.j.williams@xxxxxxxxx>
> > > > > Date: Thu Mar 22 17:05:11 2012 -0700
> > > > >
> > > > > [SCSI] sd: limit the scope of the async probe domain
> > >
> > > My theory is that this is an init problem: The assumption in a lot of
> > > our code is that async_synchronize_full() waits for everything ... even
> > > the domain specific async schedules, which isn't true.
> > >
> > > The code in init that makes this assumption is wait_for_device_probe().
> > > There's also a fun async_synchronize_full() in init_post() that assumes
> > > it can free the init memory after, which would fail badly if anything in
> > > init used an async domain.
> > >
> > > So either we fix the assumptions or we can't use domain specific async
> > > schedules.
> > >
> >
> > Hm, we already have cases of code not trusting the semantics of
> > wait_for_device_probe(), especially as it relates to async scanning like
> > in kernel/power/hibernate.c:
> >
> > /*
> > * Some device discovery might still be in progress; we need
> > * to wait for this to finish.
> > */
> > wait_for_device_probe();
> >
> > if (resume_wait) {
> > while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
> > msleep(10);
> > async_synchronize_full();
> > }
> >
> > /*
> > * We can't depend on SCSI devices being available after loading
> > * one of their modules until scsi_complete_async_scans() is
> > * called and the resume device usually is a SCSI one.
> > */
> > scsi_complete_async_scans();
>
> This is actually looks wrong: it works if SCSI is built in, but it's a
> nop if SCSI is a module (the nop function is gated by the else clause of
> #ifdef CONFIG_SCSI)
>
> Rafael, you added this not via the SCSI tree,
That's correct, it was committed directly by Linus.
> is that the intention?
Pretty much it is.
The code snippet is slightly out of context and it is a part of the
software_resume() routine, which is only called when the kernel's built-in
image reading code checks whether or not the image is present. It won't
work anyway if SCSI is not built in.
Thanks,
Rafael
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
