Re: [PATCH v2 4/7] remoteproc: Use kstrdup_const() rather than kstrup()
From: Bjorn Andersson
Date: Mon Apr 20 2020 - 01:24:37 EST
On Fri 17 Apr 06:44 PDT 2020, Suman Anna wrote:
> On 4/15/20 4:25 PM, Alex Elder wrote:
> > On 4/15/20 3:48 PM, Mathieu Poirier wrote:
> > > For cases where @firmware is declared "const char *", use function
> > > kstrdup_const() to avoid needlessly creating another copy on the
> > > heap.
> > >
> > > Suggested-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> > > Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> >
> > Looks good.
> >
> > Reviewed-by: Alex Elder <elder@xxxxxxxxxx>
> >
> > > ---
> > > drivers/remoteproc/remoteproc_core.c | 4 ++--
> > > include/linux/remoteproc.h | 2 +-
> > > 2 files changed, 3 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> > > index 9899467fa1cf..ebaff496ef81 100644
> > > --- a/drivers/remoteproc/remoteproc_core.c
> > > +++ b/drivers/remoteproc/remoteproc_core.c
> > > @@ -1982,7 +1982,7 @@ static const struct device_type rproc_type = {
> > > static int rproc_alloc_firmware(struct rproc *rproc,
> > > const char *name, const char *firmware)
> > > {
> > > - char *p;
> > > + const char *p;
> > > if (!firmware)
> > > /*
> > > @@ -1991,7 +1991,7 @@ static int rproc_alloc_firmware(struct rproc *rproc,
> > > */
> > > p = kasprintf(GFP_KERNEL, "rproc-%s-fw", name);
>
> So, to be consistent for both paths, should we be using kvasprintf_const()
> here and kfree_const() in release.
Given that the second argument is a "proper" format string
kvasprintf_const() is really just kasprintf() - but with the requirement
that we set up a va_list. So I prefer that we stick with this.
> The kfree_const() is needed to account
> for the kstrdup_const below for sure.
>
You are correct Suman, this patch needs to also change the kfree() to a
kfree_const() or bad things will happen after a visit to
rproc_type_release().
Regards,
Bjorn
> regards
> Suman
>
> > > else
> > > - p = kstrdup(firmware, GFP_KERNEL);
> > > + p = kstrdup_const(firmware, GFP_KERNEL);
> > > if (!p)
> > > return -ENOMEM;
> > > diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> > > index 9c07d7958c53..38607107b7cb 100644
> > > --- a/include/linux/remoteproc.h
> > > +++ b/include/linux/remoteproc.h
> > > @@ -489,7 +489,7 @@ struct rproc {
> > > struct list_head node;
> > > struct iommu_domain *domain;
> > > const char *name;
> > > - char *firmware;
> > > + const char *firmware;
> > > void *priv;
> > > struct rproc_ops *ops;
> > > struct device dev;
> > >
> >
>