Messages in this thread | | | From | Rusty Russell <> | Subject | Re: [PATCH 1/2] hw_random: core updates to allow more efficient drivers | Date | Sat, 28 Nov 2009 20:35:26 +1030 |
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On Thu, 26 Nov 2009 11:33:23 am Matt Mackall wrote: > On Thu, 2009-11-26 at 00:25 +0000, Ian Molton wrote: > > #define PFX RNG_MODULE_NAME ": " > > #define RNG_MISCDEV_MINOR 183 /* official */ > > +#define RNG_BUFFSIZE 64 > > How about just: > > static u8 rng_buffer[RNG_BUFFSIZE] __cacheline_aligned; > > And lose all the kmalloc and kfree code? The memory use will be smaller, > even when the buffer isn't needed.
And might as well just #defube RNG_BUFFSIZE SMP_CACHE_BYTES (or use SMP_CACHE_BYTES here and sizeof() elsewhere).
> > + if (!data_avail) { > > + bytes_read = rng_get_data(current_rng, rng_buffer, > > + RNG_BUFFSIZE, !(filp->f_flags & O_NONBLOCK)); > > No need to pass rng_buffer to the helper as there's only one with global > scope.
Naah, I like the separation; it matches the rest of the kernel and means we can get funky with buffer management in 10 years time when we rewrite this again.
Thanks, Rusty.
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