Re: [PATCH] [SCSI] sg: late O_EXCL fix for lk 3.12-rc

[Vaughan Cao]

On 2013å10æ21æ 07:00, Douglas Gilbert wrote:
> On 13-10-20 01:31 PM, Bart Van Assche wrote:
> > On 10/20/13 18:09, Douglas Gilbert wrote:
> > > Given that lk 3.12.0 release is not far away, the safest path
> > > may still be to revert Vaughan Cao's patch. I'll leave that
> > > decision to the maintainers.
> >
> > Hello Doug,
> >
> > Thanks for looking into this. But I would appreciate it if you could 
> > address the
> > whitespace errors reported by checkpatch:
> >
> > ERROR: space prohibited after that '!' (ctx:BxW)
> > #24: FILE: drivers/scsi/sg.c:241:
> > + (excl_case ? (! sdp->exclude) : sfds_list_empty(sdp))));
> > ^
> >
> > ERROR: space prohibited after that '!' (ctx:BxW)
> > #55: FILE: drivers/scsi/sg.c:289:
> > + if (! alone) {
> > ^
> >
> > ERROR: code indent should use tabs where possible
> > #59: FILE: drivers/scsi/sg.c:292:
> > + }$
> >
> > WARNING: please, no spaces at the start of a line
> > #59: FILE: drivers/scsi/sg.c:292:
> > + }$
> >
> > ERROR: space prohibited after that '!' (ctx:BxW)
> > #73: FILE: drivers/scsi/sg.c:301:
> > + while (! alone) {
> > ^
> >
> > WARNING: suspect code indent for conditional statements (8, 12)
> > #144: FILE: drivers/scsi/sg.c:375:
> > + if (excl || sfds_list_empty(sdp))
> > + wake_up_interruptible(&sdp->open_wait);
>
> I'd prefer people to test the patch or find logical flaws.
>
> Doug Gilbert
Hi Doug,

Will the lines below conflict with the meaning of NONBLOCK?
>+ down(&sdp->or_sem);
>+ alone = sfds_list_empty(sdp);
> if (!((flags & O_NONBLOCK) ||
> scsi_block_when_processing_errors(sdp->device))) {

Assume one thread holds the or_sem and waiting in 
scsi_block_when_processing_errors for the underlying scsi device to 
complete error recovery,
another thread with O_NONBLOCK call sg_open().

I'm also curious why we can skip checking _processing_errors() when 
called with O_NONBLOCK?...Though it has been there from the very beginning.
In other words, since scsi device may go into a error recovery state at 
random time, why we only check here?

Thanks,
Vaughan

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