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[222.155.4.20]) by smtp.gmail.com with ESMTPSA id o72sm8703401pjo.50.2021.10.16.18.52.13 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sat, 16 Oct 2021 18:52:15 -0700 (PDT) Subject: Re: [PATCH] ataflop: unlock ataflop_probe_lock at atari_floppy_init() To: Tetsuo Handa , linux-block@vger.kernel.org, linux-m68k@lists.linux-m68k.org, Christoph Hellwig , Luis Chamberlain References: <1d9351dc-baeb-1a54-625c-04ce01b009b0@i-love.sakura.ne.jp> From: Michael Schmitz Message-ID: <6d26961c-3b51-d6e1-fb95-b72e720ed5d0@gmail.com> Date: Sun, 17 Oct 2021 14:52:05 +1300 User-Agent: Mozilla/5.0 (X11; Linux ppc64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <1d9351dc-baeb-1a54-625c-04ce01b009b0@i-love.sakura.ne.jp> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Hi Tetsuo, thank you for fixing this bug! On 17/10/21 02:25, Tetsuo Handa wrote: > Commit bf9c0538e485b591 ("ataflop: use a separate gendisk for each media > format") introduced ataflop_probe_lock mutex, but forgot to unlock the > mutex when atari_floppy_init() (i.e. module loading) succeeded. If > ataflop_probe() is called, it will deadlock on ataflop_probe_lock mutex. > > Signed-off-by: Tetsuo Handa > Fixes: bf9c0538e485b591 ("ataflop: use a separate gendisk for each media format") > --- > To m68k users > > This patch suggests that nobody is testing this module using a real hardware. Not as a module, no. I use the Atari floppy driver built-in. Latest kernel version I ran was 5.13. Relevant kernel log excerpt: calling atari_floppy_init+0x0/0x4d4 @ 1 Atari floppy driver: max. HD, track buffering Probing floppy drive(s): fd0 initcall atari_floppy_init+0x0/0x4d4 returned 0 after 675082 usecs Haven't tried to read from the drive in a while though... waiting for floppy I/O isn't my favourite spectator sport. I take it a read attempt should fail, without your patch? > Can somebody test this module? Yes. > Is current m68k hardware still supporting Atari floppy? Yes. Cheers, Michael Schmitz > If Atari floppy is no longer supported, do we still need this module? > > To Christoph Hellwig and Luis Chamberlain > > If we move __register_blkdev() in atari_floppy_init() to the end of > atari_floppy_init() and move unregister_blkdev() in atari_floppy_exit() to > the beginning of atari_floppy_exit(), we can remove unregister_blkdev() from > atari_floppy_init(), and I think we can also remove ataflop_probe_lock mutex > because probe function and __exit function are serialized by major_names_lock > mutex. > > drivers/block/ataflop.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/block/ataflop.c b/drivers/block/ataflop.c > index a093644ac39f..39b42cb8d173 100644 > --- a/drivers/block/ataflop.c > +++ b/drivers/block/ataflop.c > @@ -2072,7 +2072,8 @@ static int __init atari_floppy_init (void) > UseTrackbuffer ? "" : "no "); > config_types(); > > - return 0; > + ret = 0; > + goto out_unlock; > > err: > while (--i >= 0) { >