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From:   Ondrej Zary <linux@zary.sk>
To:     Damien Le Moal <damien.lemoal@opensource.wdc.com>
Subject: Re: [PATCH] pata_parport: add driver (PARIDE replacement)
Date:   Mon, 14 Nov 2022 20:25:46 +0100
User-Agent: KMail/1.9.10
Cc:     Christoph Hellwig <hch@lst.de>,
        Sergey Shtylyov <s.shtylyov@omp.ru>,
        Jens Axboe <axboe@kernel.dk>, Tim Waugh <tim@cyberelk.net>,
        linux-block@vger.kernel.org, linux-parport@lists.infradead.org,
        linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20220312144415.20010-1-linux@zary.sk> <202211140853.11115.linux@zary.sk> <f8ce8ecd-cadd-d9ca-d2fa-1251804344f0@opensource.wdc.com>
In-Reply-To: <f8ce8ecd-cadd-d9ca-d2fa-1251804344f0@opensource.wdc.com>
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On Monday 14 November 2022 09:03:28 Damien Le Moal wrote:
> On 11/14/22 16:53, Ondrej Zary wrote:
> > On Monday 14 November 2022, Damien Le Moal wrote:
> >> On 11/12/22 20:17, Ondrej Zary wrote:
> >>> On Wednesday 19 October 2022 09:34:31 Christoph Hellwig wrote:
> >>>> It's been a while - did you get a chance to make some progress on
> >>>> this?  Do you need any help to unblock you?
> >>>>
> >>>
> >>> Sorry again, I'm back now. Trying to fix locking problems.
> >>> Added this to each function for analysis how the functions are called wrt.
> >>> locking:
> >>>
> >>> 	printk("%s, locked=%d\n", __FUNCTION__, spin_is_locked(ap->lock));
> >>
> >> Do you have your code somewhere that we can look at ?
> > 
> > This is the current version with debug printks. I've also added dump_stack()
> > to find out the code path but haven't analyzed the output yet.
> 
> Can you send a proper patch ? Or a link to a git tree ? That is easier to
> handle than pasted code in an email...

Patch against what? I don't have a git server.

I've done some call trace analysis. These code paths are calling
pata_parport functions with ap->lock locked during init.

Comm: kworker, Workqueue: ata_sff ata_sff_pio_task
ata_sff_hsm_move -> ata_pio_sectors-> ata_sff_altstatus -> pata_parport_tf_read -> pata_parport_check_altstatus
ata_sff_hsm_move -> ata_sff_altstatus -> pata_parport_tf_read -> pata_parport_check_altstatus
ata_sff_pio_task -> ata_sff_busy_wait -> pata_parport_check_status
ata_sff_hsm_move -> ata_wait_idle -> ata_sff_busy_wait -> pata_parport_check_status
ata_sff_hsm_move -> ata_hsm_qc_complete -> ata_sff_irq_on -> ata_wait_idle -> ata_sff_busy_wait -> pata_parport_check_status
ata_sff_pio_task -> ata_sff_hsm_move -> ata_pio_sectors -> ata_pio_sector -> ata_pio_xfer -> pata_parport_data_xfer
ata_sff_pio_task -> ata_sff_hsm_move -> pata_parport_data_xfer
ata_sff_pio_task -> ata_sff_hsm_move -> pata_parport_tf_read
ata_sff_hsm_move -> ata_hsm_qc_complete -> ata_qc_complete -> fill_result_tf -> ata_sff_qc_fill_rtf -> pata_parport_tf_read
ata_sff_hsm_move -> ata_pio_sectors -> ata_sff_altstatus -> pata_parport_check_altstatus
ata_sff_hsm_move -> ata_sff_altstatus -> pata_parport_check_altstatus

Comm: modprobe
ata_host_start -> ata_eh_freeze_port -> ata_sff_freeze -> pata_parport_check_status

Comm: scsi_eh_4
ata_eh_recover -> ata_eh_reset -> ata_eh_thaw_port -> ata_sff_thaw -> ata_sff_irq_on -> ata_wait_idle -> ata_sff_busy_wait -> pata_parport_check_status
ata_eh_reset -> ata_eh_freeze_port -> ata_sff_freeze -> pata_parport_check_status
ata_scsi_error -> ata_scsi_port_error_handler -> ata_port_freeze -> ata_sff_freeze -> pata_parport_check_status
ata_sff_error_handler -> pata_parport_drain_fifo -> pata_parport_check_status


-- 
Ondrej Zary