| Subject | Re: [PATCH v2 01/24] input: Add ff-memless-next module | From | Oliver Neukum <> | Date | Wed, 23 Apr 2014 19:06:08 +0200 |
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On Wed, 2014-04-23 at 08:59 -0700, Dmitry Torokhov wrote: > On Wed, Apr 23, 2014 at 02:12:59PM +0200, Oliver Neukum wrote: > > On Tue, 2014-04-22 at 15:59 +0200, Michal Malý wrote: > > > +/* Some devices might have a limit on how many uncombinable effects > > > + * can be played at once */ > > > +static int mlnx_upload_conditional(struct mlnx_device *mlnxdev, > > > + const struct ff_effect *effect) > > > +{ > > > + struct mlnx_effect_command ecmd = { > > > + .cmd = MLNX_UPLOAD_UNCOMB, > > > + .u.uncomb.id = effect->id, > > > + .u.uncomb.effect = effect > > > + }; > > > + return mlnxdev->control_effect(mlnxdev->dev, mlnxdev->private, > > > &ecmd); > > > +} > > > + > > > > This mean you are building the structure on the stack > > > > 1. Are you sure nobody retains a reference? > > 2. That is needlessly inefficient > > Why is it inefficient?
The compiler has to include the data structure and then make a memcopy to the stack. Instead a pointer to the predined structure could be passed.
Regards Oliver
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