Hi!
On 19:36 Wed 28 Apr , calix wrote:
> Hi,
>
> When I use copy_from_user(void *to, const void __user *from, unsigned long
> n), should the n is less than a PAGESIZE?
It does not need to be smallor than PAGESIZE, but it must not be larger than
either the user space buffer or kernel space buffer. Allocating more than
PAGESIZE in kernel space is usually not such good idea, because it might
easily be much slower. Note that kernel space buffers must be physically
continuous (except when using vmalloc, which is even slower) and memory
fragmentation might cause slowdowns.
-Michi
--
programing a layer 3+4 network protocol for mesh networks
see http://michaelblizek.twilightparadox.com
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