Re: [PATCH v2] tpm: fix TIS locality timeout problems

[Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>]

On Thu, May 28, 2020 at 11:10:57AM -0700, James Bottomley wrote:
> It has been reported that some TIS based TPMs are giving unexpected
> errors when using the O_NONBLOCK path of the TPM device. The problem
> is that some TPMs don't like it when you get and then relinquish a
> locality (as the tpm_try_get_ops()/tpm_put_ops() pair does) without
> sending a command.  This currently happens all the time in the
> O_NONBLOCK write path. Fix this by moving the tpm_try_get_ops()
> further down the code to after the O_NONBLOCK determination is made.
> This is safe because the priv->buffer_mutex still protects the priv
> state being modified.
> 
> BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=206275
> Fixes: d23d12484307 ("tpm: fix invalid locking in NONBLOCKING mode")
> Reported-by: Mario Limonciello <Mario.Limonciello@dell.com>
> Tested-by: Alex Guzman <alex@guzman.io>
> Cc: stable@vger.kernel.org
> Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

Thanks a lot! Merging this soon.

Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

/Jarko