Re: [PATCH] Avoid that ATA error handling hangs

[Bart Van Assche <Bart.VanAssche@wdc.com>]

On Thu, 2018-02-22 at 02:23 +0000, Damien Le Moal wrote:
> On Wed, 2018-02-21 at 09:23 -0800, Bart Van Assche wrote:
> > [ ... ]
> This does not compile.

This patch depends on another patch that is not yet in Martin's tree. See also
https://marc.info/?l=linux-scsi&m=151675130615597. I should have mentioned this
in the patch description.

> Testing this, the rcu hang is now gone.

Thanks for the testing :-)

> However, the behavior of the error recovery  is still different from what I
> see in 4.15 and 4.14. For my test case, an unaligned write to a sequential
> zone on a ZAC drive connected to an AHCI port, the report zone issued during
> the disk revalidation after the write error fails with a timeout, which causes
> capacity change to 0, port reset and recovery again. Eventually, everything
> comes back up OK, but it takes some time.
> 
> I am investigating to make sure I am not hitting a device FW bug to confirm if
> this is a kernel problem.

This patch was tested with the SRP protocol. I'm not an ATA expert but I hope
that someone who is more familiar with ATA than I can chime in.

Bart.