Messages in this thread Patch in this message | | | Subject | Re: [PATCH 1/2] hw_random: core updates to allow more efficient drivers | From | Matt Mackall <> | Date | Wed, 25 Nov 2009 19:03:23 -0600 |
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On Thu, 2009-11-26 at 00:25 +0000, Ian Molton wrote: > This patch implements a new method by which hw_random hardware drivers > can pass data to the core more efficiently, using a shared buffer. > > The old methods have been retained as a compatability layer until all the > drivers have been updated. > > Signed-off-by: Ian Molton <ian.molton@collabora.co.uk> > --- > drivers/char/hw_random/core.c | 120 ++++++++++++++++++++++++++--------------- > include/linux/hw_random.h | 9 ++- > 2 files changed, 82 insertions(+), 47 deletions(-) > > diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c > index 1573aeb..e179afd 100644 > --- a/drivers/char/hw_random/core.c > +++ b/drivers/char/hw_random/core.c > @@ -47,12 +47,14 @@ > #define RNG_MODULE_NAME "hw_random" > #define PFX RNG_MODULE_NAME ": " > #define RNG_MISCDEV_MINOR 183 /* official */ > +#define RNG_BUFFSIZE 64 > > > static struct hwrng *current_rng; > static LIST_HEAD(rng_list); > static DEFINE_MUTEX(rng_mutex); > - > +static u8 *rng_buffer;
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.
> + 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.
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