Hi Julia,
On Wednesday 02 Nov 2016 07:24:29 Julia Lawall wrote:
> On Wed, 2 Nov 2016, Nadim Almas wrote:
> > Switch to resource-managed function devm_kzalloc instead
> > of kzolloc and remove unneeded kzfree
> >
> > Also, remove kzfree in probe function and remove
> > function,vpfe_remove as it is now has nothing to do.
> > The Coccinelle semantic patch used to make this change is as follows:
> > /<smpl>
> > @platform@
> > identifier p, probefn, removefn;
> > @@
> > struct platform_driver p = {
> > .probe = probefn,
> > .remove = removefn,
> > };
> >
> > @prb@
> > identifier platform.probefn, pdev;
> > expression e, e1, e2;
> > @@
> > probefn(struct platform_device *pdev, ...) {
> > <+...
> > - e = kzalloc(e1, e2)
> > + e = devm_kzalloc(&pdev->dev, e1, e2)
> > ...
> > ?-kzfree(e);
> > ...+>
> > }
> > @rem depends on prb@
> > identifier platform.removefn;
> > expression prb.e;
> > @@
> > removefn(...) {
> > <...
> > - kzfree(e);
> > ...>
> > }
> > //</smpl>
> >
> > Signed-off-by: Nadim Almas <nadim.902@xxxxxxxxx>
> > ---
> >
> > drivers/staging/media/davinci_vpfe/vpfe_mc_capture.c | 4 +---
> > 1 file changed, 1 insertion(+), 3 deletions(-)
> >
> > diff --git a/drivers/staging/media/davinci_vpfe/vpfe_mc_capture.c
> > b/drivers/staging/media/davinci_vpfe/vpfe_mc_capture.c index
> > bf077f8..cd44f0f 100644
> > --- a/drivers/staging/media/davinci_vpfe/vpfe_mc_capture.c
> > +++ b/drivers/staging/media/davinci_vpfe/vpfe_mc_capture.c
> > @@ -579,7 +579,7 @@ static int vpfe_probe(struct platform_device *pdev)
> > struct resource *res1;
> > int ret = -ENOMEM;
> >
> > - vpfe_dev = kzalloc(sizeof(*vpfe_dev), GFP_KERNEL);
> > + vpfe_dev = devm_kzalloc(&pdev->dev, sizeof(*vpfe_dev), GFP_KERNEL);
> > if (!vpfe_dev)
> > return ret;
> >
> > @@ -681,7 +681,6 @@ static int vpfe_probe(struct platform_device *pdev)
> > probe_disable_clock:
> > vpfe_disable_clock(vpfe_dev);
> > probe_free_dev_mem:
> > - kzfree(vpfe_dev);
>
> Kzfree zeroes the data before freeing it. Devm_kzalloc only causes a
> kfree to happen, not a kzfree. If the kzfree is needed, then a memset 0
> would need to replace the calls to kzfree.
I don't think kzfree() is needed in this case.
> There are some other minor issues with the patch. In the subject line,
> there is normally a space after each :. There is a spelling mistake in
> the commit message. In the commit message there should be one space
> betwee words within a sentence, and there should be a space after a comma,
> or other puctuation.
Beside, I don't think devm_kzalloc() is a good idea. The vpfe_device structure
embeds data accessible from userspace through ioctls, and thus potentially
needs to survive unbinding the driver from the device. This isn't currently
implemented now, but devm_kzalloc() just goes in the wrong direction.
> > return ret;
> > }
> >
> > @@ -702,7 +701,6 @@ static int vpfe_remove(struct platform_device *pdev)
> > v4l2_device_unregister(&vpfe_dev->v4l2_dev);
> > media_device_unregister(&vpfe_dev->media_dev);
> > vpfe_disable_clock(vpfe_dev);
> > - kzfree(vpfe_dev);
> > return 0;
> > }
> >
--
Regards,
Laurent Pinchart
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