Re: [GIT] Networking

Julia Lawall
2015-09-03T20:55:48Z

On Thu, 3 Sep 2015, Linus Torvalds wrote:

> On Thu, Sep 3, 2015 at 12:32 PM, Julia Lawall <julia.lawall@lip6.fr> wrote:
> >
> > I find 518 occurrences of a function parameter declaration that contains
> > an explicit size. But only the sizeof(mcs_mask) where there is a sizeof
> > on such a parameter. I also checked for ARRAY_SIZE on such parameters,
> > and didn't find any occurrences of that either.
>
> Are there any cases of multi-dimensional arrays? Because those
> actually have semantic meaning outside of sizeof(), just in things
> like adding offsets.
>
> Eg something like
>
> int fn(int a[][10])
>
> ends up being equivalent to something like
>
> int fn(int (*a)[10])
>
> and "a+1" is actually 40 bytes ahead of "a", so it does *not* act like
> an "int *".
>
> (And I might have screwed that up mightily - C multidimensional arrays
> and the conversions to pointers are really easy to get confused about.
> Which is why I hope we don't have them)

There are 32 2-dimensional arrays in function parameters, and 1
3-dimensional array. No 4-dimensional arrays. I didn't check past that.
None of these has a sizeof or ARRAY_SIZE.

The three dimensional array is here: drivers/media/dvb-frontends/stv0367.c

static int stv0367ter_filt_coeff_init(struct stv0367_state *state,
u16 CellsCoeffs[3][6][5], u32 DemodXtal)

It is used as follows:

stv0367_writereg(state,
(R367TER_IIRCX_COEFF1_MSB + 2 * (j - 1)),
MSB(CellsCoeffs[k][i-1][j-1]));
stv0367_writereg(state,
(R367TER_IIRCX_COEFF1_LSB + 2 * (j - 1)),
LSB(CellsCoeffs[k][i-1][j-1]));

The value of this parameter is one of three locally defined static global
arrays.

julia