On Tue, Apr 24, 2018 at 08:04:01PM +0000, Winkler, Tomas wrote:

quoted

quoted

Subject: Re: [PATCH] tpm: tpm_crb: relinquish locality on error path.

On Fri, Apr 20, 2018 at 01:19:12PM +0000, Winkler, Tomas wrote:

quoted

quoted

quoted

On Tue, 2018-04-10 at 09:00 +0000, Winkler, Tomas wrote:

quoted

quoted

On Sat, 2018-04-07 at 19:12 +0300, Tomas Winkler wrote:

quoted

In crb_map_io() function, __crb_request_locality() is
called prior to crb_cmd_ready(), but if one of the
consecutive function fails the flow bails out instead of
trying to relinquish

locality.

quoted

quoted

quoted

quoted

quoted

quoted

This patch adds goto jump to __crb_relinquish_locality()
on the error path.

Fixes: 888d867df441 (tpm: cmd_ready command can be
issued only after granting
locality)
Signed-off-by: Tomas Winkler <redacted>
---
 drivers/char/tpm/tpm_crb.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/char/tpm/tpm_crb.c

b/drivers/char/tpm/tpm_crb.c index
7f78482cd157..34fbc6cb097b
100644

--- a/drivers/char/tpm/tpm_crb.c
+++ b/drivers/char/tpm/tpm_crb.c

@@ -511,8 +511,10 @@ static int crb_map_io(struct

acpi_device *device, struct crb_priv *priv,

 	priv->regs_t = crb_map_res(dev, priv, &io_res, buf-

quoted

control_address,

 				   sizeof(struct crb_regs_tail));
-	if (IS_ERR(priv->regs_t))
-		return PTR_ERR(priv->regs_t);
+	if (IS_ERR(priv->regs_t)) {
+		ret = PTR_ERR(priv->regs_t);
+		goto out_relinquish_locality;
+	}

 	/*
 	 * PTT HW bug w/a: wake up the device to access @@
-520,7
+522,7

@@

quoted

static int crb_map_io(struct acpi_device *device, struct
crb_priv *priv,
 	 */
 	ret = crb_cmd_ready(dev, priv);
 	if (ret)
-		return ret;
+		goto out_relinquish_locality;

 	pa_high = ioread32(&priv->regs_t->ctrl_cmd_pa_high);
 	pa_low  = ioread32(&priv->regs_t->ctrl_cmd_pa_low);

@@ -565,6 +567,8 @@ static int crb_map_io(struct

acpi_device *device, struct crb_priv *priv,

 	crb_go_idle(dev, priv);

+out_relinquish_locality:
+
 	__crb_relinquish_locality(dev, priv, 0);

 	return ret;

Thanks, please just call it before returning in the error path.

Can you please elaborate why, isn't the centralized exiting
of functions preferred kernel coding style?
https://www.kernel.org/doc/html/v4.11/process/coding-style.h
tml#
cent
ra
lized-ex
iting-of-functions

You exit only from one location (not multiple) and not from a
nested context. Here you just add more complexity by doing this.

Where is the complexity ? I see it as a standard way of undoing on

exit.

quoted

quoted

quoted

quoted

Tomas

Jarkko, can you please respond.
Thanks
Tomas

I was away for Mon-Wed last week and did not work on TPM for Thu-Fri.

My earlier comment was incorrect as there are two locations to exit
(not sure how I managed to overlook the patch that way).

Thus, I have only two very  minor requets:

* Remove the extra newline (the last line addition in the patch).

Okay

quoted

* Use just label named out as we have only one exception handler.

Cannot do that, as the bail out is prior to cmd_ready request so there is no

need for go_idle which is under out label.

quoted

quoted

I'll move on to testing, and if it it passes, I can do those updates myself.

Thanks,  I prefer to resend myself.

Tomas

Add my tested-by as it is cosmectic change, thanks.

What change exactly? I had impression you've accepted the patch as is?
Thanks
Tomas