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SubjectRE: [PATCH] tpm: tpm_crb: relinquish locality on error path.
Date
> 
> On Sat, 2018-04-07 at 19:12 +0300, Tomas Winkler wrote:
> > 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.
> > 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 <tomas.winkler@intel.com>
> > ---
> > 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->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
> @@
> > 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.html#centralized-exiting-of-functions

Thanks
Tomas

>
> /Jarkko
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