| Message ID | 20190104174327.GA30932@embeddedor |
|---|---|
| State | Accepted |
| Delegated to: | Peter Rosin |
| Headers | show |
| Series | i2c: mux: demux-pinctrl: use struct_size() in devm_kzalloc() | expand |
> Instead of leaving these open-coded and prone to type mistakes, we can > now use the new struct_size() helper: I am okay with this patch in general. However, I think the name of the helper 'struct_size' is a bit unfortunate. I really wondered on the first read why it needs 3 arguments to find out a struct size. I only understood on the second read. I think 'trailing_array_struct_size' would be way more clearer what it does.
On 2019-01-04 19:06, Wolfram Sang wrote: > >> Instead of leaving these open-coded and prone to type mistakes, we can >> now use the new struct_size() helper: > > I am okay with this patch in general. However, I think the name of the > helper 'struct_size' is a bit unfortunate. I really wondered on the > first read why it needs 3 arguments to find out a struct size. I only > understood on the second read. I think 'trailing_array_struct_size' > would be way more clearer what it does. I read that as an Acked-by... :-) Cheers, Peter
On Sun, Apr 21, 2019 at 06:15:21PM +0000, Peter Rosin wrote: > On 2019-01-04 19:06, Wolfram Sang wrote: > > > >> Instead of leaving these open-coded and prone to type mistakes, we can > >> now use the new struct_size() helper: > > > > I am okay with this patch in general. However, I think the name of the > > helper 'struct_size' is a bit unfortunate. I really wondered on the > > first read why it needs 3 arguments to find out a struct size. I only > > understood on the second read. I think 'trailing_array_struct_size' > > would be way more clearer what it does. > > I read that as an Acked-by... :-) For this patch, yes. Thanks!
diff --git a/drivers/i2c/muxes/i2c-demux-pinctrl.c b/drivers/i2c/muxes/i2c-demux-pinctrl.c index 035032e20327..012b45e447c3 100644 --- a/drivers/i2c/muxes/i2c-demux-pinctrl.c +++ b/drivers/i2c/muxes/i2c-demux-pinctrl.c @@ -219,8 +219,8 @@ static int i2c_demux_pinctrl_probe(struct platform_device *pdev) return -EINVAL; } - priv = devm_kzalloc(&pdev->dev, sizeof(*priv) - + num_chan * sizeof(struct i2c_demux_pinctrl_chan), GFP_KERNEL); + priv = devm_kzalloc(&pdev->dev, struct_size(priv, chan, num_chan), + GFP_KERNEL); props = devm_kcalloc(&pdev->dev, num_chan, sizeof(*props), GFP_KERNEL);
One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct foo { int stuff; void *entry[]; }; instance = devm_kzalloc(dev, sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = devm_kzalloc(dev, struct_size(instance, entry, count), GFP_KERNEL); This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> --- drivers/i2c/muxes/i2c-demux-pinctrl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)