[PATCH 5/5] spi: fix return value check in hspi_probe().

[PATCH 5/5] spi: fix return value check in hspi_probe().

[Cyril Roelandt]

According to its documentation, clk_get() returns a "valid IS_ERR() condition
containing errno", so we should call IS_ERR() rather than a NULL check.

Signed-off-by: Cyril Roelandt <tipecaml-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/spi/spi-sh-hspi.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-sh-hspi.c b/drivers/spi/spi-sh-hspi.c
index 32f7b55..60cfae5 100644
--- a/drivers/spi/spi-sh-hspi.c
+++ b/drivers/spi/spi-sh-hspi.c
@@ -290,7 +290,7 @@ static int hspi_probe(struct platform_device *pdev)
 	}
 
 	clk = clk_get(NULL, "shyway_clk");
-	if (!clk) {
+	if (IS_ERR(clk)) {
 		dev_err(&pdev->dev, "shyway_clk is required\n");
 		ret = -EINVAL;
 		goto error0;
-- 
1.7.10.4


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Re: [PATCH 5/5] spi: fix return value check in hspi_probe().

[Kuninori Morimoto]

Hi

> According to its documentation, clk_get() returns a "valid IS_ERR() condition
> containing errno", so we should call IS_ERR() rather than a NULL check.
> 
> Signed-off-by: Cyril Roelandt <tipecaml-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

Acked-by: Kuninori Morimoto <kuninori.morimoto.gx-zM6kxYcvzFBBDgjK7y7TUQ@public.gmane.org>

> ---
>  drivers/spi/spi-sh-hspi.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/spi/spi-sh-hspi.c b/drivers/spi/spi-sh-hspi.c
> index 32f7b55..60cfae5 100644
> --- a/drivers/spi/spi-sh-hspi.c
> +++ b/drivers/spi/spi-sh-hspi.c
> @@ -290,7 +290,7 @@ static int hspi_probe(struct platform_device *pdev)
>  	}
>  
>  	clk = clk_get(NULL, "shyway_clk");
> -	if (!clk) {
> +	if (IS_ERR(clk)) {
>  		dev_err(&pdev->dev, "shyway_clk is required\n");
>  		ret = -EINVAL;
>  		goto error0;
> -- 
> 1.7.10.4
> 
> 
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> _______________________________________________
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> https://lists.sourceforge.net/lists/listinfo/spi-devel-general


Best regards
---
Kuninori Morimoto

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Re: [PATCH 5/5] spi: fix return value check in hspi_probe().

[Grant Likely]

On Tue, 11 Dec 2012 16:36:27 -0800 (PST), Kuninori Morimoto <kuninori.morimoto.gx-zM6kxYcvzFBBDgjK7y7TUQ@public.gmane.org> wrote:
> 
> Hi
> 
> > According to its documentation, clk_get() returns a "valid IS_ERR() condition
> > containing errno", so we should call IS_ERR() rather than a NULL check.
> > 
> > Signed-off-by: Cyril Roelandt <tipecaml-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> 
> Acked-by: Kuninori Morimoto <kuninori.morimoto.gx-zM6kxYcvzFBBDgjK7y7TUQ@public.gmane.org>

Applied, thanks.

g.


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Re: [PATCH 5/5] spi: fix return value check in hspi_probe().

[Dan Carpenter]

On Wed, Dec 19, 2012 at 03:11:54PM +0000, Grant Likely wrote:
> On Tue, 11 Dec 2012 16:36:27 -0800 (PST), Kuninori Morimoto <kuninori.morimoto.gx-zM6kxYcvzFBBDgjK7y7TUQ@public.gmane.org> wrote:
> > 
> > Hi
> > 
> > > According to its documentation, clk_get() returns a "valid IS_ERR() condition
> > > containing errno", so we should call IS_ERR() rather than a NULL check.
> > > 
> > > Signed-off-by: Cyril Roelandt <tipecaml-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> > 
> > Acked-by: Kuninori Morimoto <kuninori.morimoto.gx-zM6kxYcvzFBBDgjK7y7TUQ@public.gmane.org>
> 
> Applied, thanks.

In another thread, we were just talking about who clk_get() can
return a NULL if !CONFIG_HAVE_CLK.  That might change to match the
documentation later...  Not sure.

regards,
dan carpenter


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Re: [PATCH 5/5] spi: fix return value check in hspi_probe().

[Grant Likely]

On Wed, 19 Dec 2012 19:39:14 +0300, Dan Carpenter <dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> wrote:
> On Wed, Dec 19, 2012 at 03:11:54PM +0000, Grant Likely wrote:
> > On Tue, 11 Dec 2012 16:36:27 -0800 (PST), Kuninori Morimoto <kuninori.morimoto.gx-zM6kxYcvzFBBDgjK7y7TUQ@public.gmane.org> wrote:
> > > 
> > > Hi
> > > 
> > > > According to its documentation, clk_get() returns a "valid IS_ERR() condition
> > > > containing errno", so we should call IS_ERR() rather than a NULL check.
> > > > 
> > > > Signed-off-by: Cyril Roelandt <tipecaml-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> > > 
> > > Acked-by: Kuninori Morimoto <kuninori.morimoto.gx-zM6kxYcvzFBBDgjK7y7TUQ@public.gmane.org>
> > 
> > Applied, thanks.
> 
> In another thread, we were just talking about who clk_get() can
> return a NULL if !CONFIG_HAVE_CLK.  That might change to match the
> documentation later...  Not sure.

So what is the solution here? Will the dummy clk_get() be changed, or is
there more work needed on the drivers?

/me stifles a rant about the PTR_ERR pattern

g.

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Re: [PATCH 5/5] spi: fix return value check in hspi_probe().

[Dan Carpenter]

On Sat, Dec 22, 2012 at 09:56:20AM +0000, Grant Likely wrote:
> On Wed, 19 Dec 2012 19:39:14 +0300, Dan Carpenter <dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> wrote:
> > On Wed, Dec 19, 2012 at 03:11:54PM +0000, Grant Likely wrote:
> > > On Tue, 11 Dec 2012 16:36:27 -0800 (PST), Kuninori Morimoto <kuninori.morimoto.gx-zM6kxYcvzFBBDgjK7y7TUQ@public.gmane.org> wrote:
> > > > 
> > > > Hi
> > > > 
> > > > > According to its documentation, clk_get() returns a "valid IS_ERR() condition
> > > > > containing errno", so we should call IS_ERR() rather than a NULL check.
> > > > > 
> > > > > Signed-off-by: Cyril Roelandt <tipecaml-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> > > > 
> > > > Acked-by: Kuninori Morimoto <kuninori.morimoto.gx-zM6kxYcvzFBBDgjK7y7TUQ@public.gmane.org>
> > > 
> > > Applied, thanks.
> > 
> > In another thread, we were just talking about who clk_get() can
> > return a NULL if !CONFIG_HAVE_CLK.  That might change to match the
> > documentation later...  Not sure.
> 
> So what is the solution here? Will the dummy clk_get() be changed, or is
> there more work needed on the drivers?
> 

This driver can't function without a clk.  It should select that at
build time instead of testing for it at probe.  Just checking for
IS_ERR() will NOT cause a NULL dereference so the patch is ok in
that respect.  I'm not sure if this can be build without
CONFIG_HAVE_CLK.

regards,
dan carpenter


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Re: [PATCH 5/5] spi: fix return value check in hspi_probe().

[Grant Likely]

On Thu, 3 Jan 2013 19:04:55 +0300, Dan Carpenter <dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> wrote:
> On Sat, Dec 22, 2012 at 09:56:20AM +0000, Grant Likely wrote:
> > On Wed, 19 Dec 2012 19:39:14 +0300, Dan Carpenter <dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> wrote:
> > > On Wed, Dec 19, 2012 at 03:11:54PM +0000, Grant Likely wrote:
> > > > On Tue, 11 Dec 2012 16:36:27 -0800 (PST), Kuninori Morimoto <kuninori.morimoto.gx-zM6kxYcvzFBBDgjK7y7TUQ@public.gmane.org> wrote:
> > > > > 
> > > > > Hi
> > > > > 
> > > > > > According to its documentation, clk_get() returns a "valid IS_ERR() condition
> > > > > > containing errno", so we should call IS_ERR() rather than a NULL check.
> > > > > > 
> > > > > > Signed-off-by: Cyril Roelandt <tipecaml-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> > > > > 
> > > > > Acked-by: Kuninori Morimoto <kuninori.morimoto.gx-zM6kxYcvzFBBDgjK7y7TUQ@public.gmane.org>
> > > > 
> > > > Applied, thanks.
> > > 
> > > In another thread, we were just talking about who clk_get() can
> > > return a NULL if !CONFIG_HAVE_CLK.  That might change to match the
> > > documentation later...  Not sure.
> > 
> > So what is the solution here? Will the dummy clk_get() be changed, or is
> > there more work needed on the drivers?
> > 
> 
> This driver can't function without a clk.  It should select that at
> build time instead of testing for it at probe.  Just checking for
> IS_ERR() will NOT cause a NULL dereference so the patch is ok in
> that respect.  I'm not sure if this can be build without
> CONFIG_HAVE_CLK.

Your suggestion is to make this driver depend on CONFIG_HAVE_CLK? I'm
fine with that, but it doesn't sort out the core infrastructure question
about whether it is valid for the empty clk_get() to return NULL. Nor is
it a particularly sustainable solution (ie. if a large number of drivers
want to do the same thing).

g.

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Re: [PATCH 5/5] spi: fix return value check in hspi_probe().

[Dan Carpenter]

On Fri, Jan 11, 2013 at 03:02:02PM +0000, Grant Likely wrote:
> On Thu, 3 Jan 2013 19:04:55 +0300, Dan Carpenter <dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> wrote:
> > On Sat, Dec 22, 2012 at 09:56:20AM +0000, Grant Likely wrote:
> > > On Wed, 19 Dec 2012 19:39:14 +0300, Dan Carpenter <dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org> wrote:
> > > > On Wed, Dec 19, 2012 at 03:11:54PM +0000, Grant Likely wrote:
> > > > > On Tue, 11 Dec 2012 16:36:27 -0800 (PST), Kuninori Morimoto <kuninori.morimoto.gx-zM6kxYcvzFBBDgjK7y7TUQ@public.gmane.org> wrote:
> > > > > > 
> > > > > > Hi
> > > > > > 
> > > > > > > According to its documentation, clk_get() returns a "valid IS_ERR() condition
> > > > > > > containing errno", so we should call IS_ERR() rather than a NULL check.
> > > > > > > 
> > > > > > > Signed-off-by: Cyril Roelandt <tipecaml-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> > > > > > 
> > > > > > Acked-by: Kuninori Morimoto <kuninori.morimoto.gx-zM6kxYcvzFBBDgjK7y7TUQ@public.gmane.org>
> > > > > 
> > > > > Applied, thanks.
> > > > 
> > > > In another thread, we were just talking about who clk_get() can
> > > > return a NULL if !CONFIG_HAVE_CLK.  That might change to match the
> > > > documentation later...  Not sure.
> > > 
> > > So what is the solution here? Will the dummy clk_get() be changed, or is
> > > there more work needed on the drivers?
> > > 
> > 
> > This driver can't function without a clk.  It should select that at
> > build time instead of testing for it at probe.  Just checking for
> > IS_ERR() will NOT cause a NULL dereference so the patch is ok in
> > that respect.  I'm not sure if this can be build without
> > CONFIG_HAVE_CLK.
> 
> Your suggestion is to make this driver depend on CONFIG_HAVE_CLK? I'm
> fine with that, but it doesn't sort out the core infrastructure question
> about whether it is valid for the empty clk_get() to return NULL. Nor is
> it a particularly sustainable solution (ie. if a large number of drivers
> want to do the same thing).
> 

We've spread this conversation out across several different threads.

http://lists.infradead.org/pipermail/linux-arm-kernel/2013-January/139186.html

Basically, drivers should use accessor functions which handle NULL
pointers instead of dereferencing the pointer directly.

regards,
dan carpenter


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