Re: [RFC][PATCH V3] axi: add AXI bus driver

From: RafaÅ MiÅecki
Date: Tue Apr 12 2011 - 07:40:43 EST

2011/4/12 RafaÅ MiÅecki <zajec5@xxxxxxxxx>:
> 2011/4/12 Greg KH <greg@xxxxxxxxx>:
>> On Tue, Apr 12, 2011 at 12:45:33AM +0200, RafaÅ MiÅecki wrote:
>>> 2011/4/12 Greg KH <greg@xxxxxxxxx>:
>>> > Then in your release function, free the struct axi_device. ÂIt's that
>>> > simple. ÂTo try to free it before then would be wrong and cause
>>> > problems.
>>> This is because it is defined as:
>>> struct axi_device cores[AXI_MAX_NR_CORES];
>> No way, seriously?
>> You can't do that, no static struct devices please. ÂMake these dynamic
>> and everything will be fine. ÂThe -mm tree used to have a huge warning
>> if you ever tried to register a statically allocated struct, but that
>> didn't really work out, but would have saved you a lot of time here,
>> sorry.
>> So dynamically allocate the structures and you will be fine.
> Well, I saw that along kernel, I had no idea there is anything wrong
> about this. It seems more ppl do not know about this:
> struct radeon_ib    Âibs[RADEON_IB_POOL_SIZE];
> struct radeon_pm_clock_info clock_info[8];
> struct radeon_pm_profile profiles[PM_PROFILE_MAX];
> struct radeon_surface_reg surface_regs[RADEON_GEM_MAX_SURFACES];
> struct radeon_i2c_chan *i2c_bus[RADEON_MAX_I2C_BUS];
> struct b43_key key[B43_NR_GROUP_KEYS * 2 + B43_NR_PAIRWISE_KEYS];
> struct ssb_device devices[SSB_MAX_NR_CORES];
> I guess I could fine more examples by simple grepping .h files.
> Is there some guide around with things like this we should avoid?
> checkpatch does no catch this, so maybe just some manual? Could you
> point me to it?

Greg, my:
struct ssb_device devices[SSB_MAX_NR_CORES];
is part of "struct axi_bus", which we allocate dynamically anyway:

struct axi_bus *bus;
bus = kzalloc(sizeof(*bus), GFP_KERNEL);
if (!bus)
goto out;

So do we really need to dynamically alloc main structure and
separately every of it's array of structs? Does it really make sense?
Please point me to some place where I can read more about this. Some
tips about coding style for such things, cases.

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