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From: Arnd Bergmann <arnd@arndb.de>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: Jens Axboe <axboe@kernel.dk>,
	Christoph Hellwig <hch@infradead.org>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	John Kacur <jkacur@redhat.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	linux-scsi@vger.kernel.org
Subject: Re: [PATCH 2/6] block: push down BKL into .open and .release
Date: Sun, 4 Jul 2010 23:09:09 +0200	[thread overview]
Message-ID: <201007042309.09727.arnd@arndb.de> (raw)
In-Reply-To: <20100704080146.GA31828@merkur.ravnborg.org>

On Sunday 04 July 2010 10:01:46 Sam Ravnborg wrote:
> > --- a/drivers/block/amiflop.c
> > +++ b/drivers/block/amiflop.c
> > @@ -1555,10 +1555,13 @@ static int floppy_open(struct block_device *bdev, fmode_t mode)
> >  	int old_dev;
> >  	unsigned long flags;
> >  
> > +	lock_kernel();
> >  	old_dev = fd_device[drive];
> >  
> > -	if (fd_ref[drive] && old_dev != system)
> > +	if (fd_ref[drive] && old_dev != system) {
> > +		unlock_kernel();
> >  		return -EBUSY;
> > +	}
> >  
> >  	if (mode & (FMODE_READ|FMODE_WRITE)) {
> >  		check_disk_change(bdev);
> > @@ -1571,8 +1574,10 @@ static int floppy_open(struct block_device *bdev, fmode_t mode)
> >  			fd_deselect (drive);
> >  			rel_fdc();
> >  
> > -			if (wrprot)
> > +			if (wrprot) {
> > +				unlock_kernel();
> >  				return -EROFS;
> > +			}
> >  		}
> >  	}
> >  
> > @@ -1589,6 +1594,7 @@ static int floppy_open(struct block_device *bdev, fmode_t mode)
> >  	printk(KERN_INFO "fd%d: accessing %s-disk with %s-layout\n",drive,
> >  	       unit[drive].type->name, data_types[system].name);
> >  
> > +	unlock_kernel();
> >  	return 0;
> >  }
> 
> Using goto for errorhandling here would have been nicer.

I tried to minimize the chance for breaking stuff in code I cannot easily
test build. As shown by the bug you found in my pktcdvd patch, changing the
control flow of a function has a higher potential of introducing bugs,
so I didn't do it for drivers that people don't care much about any more.

> Also did you forget to include smp_locks.h?

No, that was already there from the first patch.

> Lot's of other places could benefit from improved goto error handling.
> The driver maintainers should do this (if there is a maintainer).

If that makes Jens accept my patches, I'd gladly change them this way.
I agree that it's cleaner and I always write my own code like that,
but when modifying (mostly) unmaintained code, my preference is on
trying to ensure the patch is correct.


> I did not find anything else going through this patch.

Ok, thanks a lot for looking through this!

	Arnd

  parent reply	other threads:[~2010-07-04 21:09 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-03 21:47 [PATCH 0/6] block: BKL removal, version 3 Arnd Bergmann
2010-07-03 21:47 ` [PATCH 1/6] block: push down BKL into .locked_ioctl Arnd Bergmann
2010-07-04  7:30   ` Sam Ravnborg
2010-07-04 20:59     ` Arnd Bergmann
2010-07-07  1:52   ` Christoph Hellwig
2010-07-07 13:28     ` Arnd Bergmann
2010-07-03 21:47 ` [PATCH 2/6] block: push down BKL into .open and .release Arnd Bergmann
2010-07-04  8:01   ` Sam Ravnborg
2010-07-04 17:33     ` Arjan van de Ven
2010-07-04 20:27       ` Geert Uytterhoeven
2010-07-04 21:09     ` Arnd Bergmann [this message]
2010-07-07  1:50   ` Christoph Hellwig
2010-07-07 14:04     ` Arnd Bergmann
2010-07-03 21:47 ` [PATCH 3/6] block: push BKL into blktrace ioctls Arnd Bergmann
2010-07-07  1:50   ` Christoph Hellwig
2010-07-07 13:46     ` Arnd Bergmann
2010-07-03 21:47 ` [PATCH 4/6] block: remove BKL from BLKROSET and BLKFLSBUF Arnd Bergmann
2010-07-07  1:52   ` Christoph Hellwig
2010-07-03 21:47 ` [PATCH 5/6] block: remove BKL from partition code Arnd Bergmann
2010-07-07  2:04   ` Christoph Hellwig
2010-07-03 21:47 ` [PATCH 6/6] scsi/sd: remove big kernel lock Arnd Bergmann
2010-07-07  2:06   ` Christoph Hellwig
2010-07-07 13:54     ` Arnd Bergmann

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