data transfer limit using ioctl()?

data transfer limit using ioctl()?

[Parav Pandit]

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Hi,
   
  How much maximum data transfer should be done using ioctl() to driver?
   
  I can also use the Netlink sockets to transfer data from user to kernel.
  Is there any limit that we should consider for choosing ioctl() to driver or using netlink sockets?
   
  Regards,
  Parav Pandit
   
   
   

 
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Re: data transfer limit using ioctl()?

[Arnd Bergmann]

On Wednesday 13 December 2006 10:24, Parav Pandit wrote:
> =A0 How much maximum data transfer should be done using ioctl() to driver?

No, there is no technical limit. Usually, it's considered good style
to transfer only a basic data type with fixed length though, like uint32_t
or loff_t, not a long buffer. You should also make sure you have a fixed
length buffer, and that it's the same size on 32 and 64 bit kernels.

=46or long non-structured transfers, use read/write operations if possible.

> =A0 I can also use the Netlink sockets to transfer data from user to kern=
el.
> =A0 Is there any limit that we should consider for choosing ioctl() to dr=
iver or using netlink sockets?
> =A0 =A0
No, that decision does not depend on the data size mostly, but more on
what you want to do.

	Arnd <><