2014-07-25 22:19:23

by Stephen Boyd

Subject: [PATCH] hwrng: Pass entropy to add_hwgenerator_randomness() in bits, not bytes

rng_get_data() returns the number of bytes read from the hardware.
The entropy argument to add_hwgenerator_randomness() is passed
directly to credit_entropy_bits() so we should be passing the
number of bits, not bytes here.

Fixes: be4000bc464 "hwrng: create filler thread"
Cc: Torsten Duwe <[email protected]>
Signed-off-by: Stephen Boyd <[email protected]>
---
drivers/char/hw_random/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index dc80cdab733d..6e02ec103cc7 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -362,7 +362,7 @@ static int hwrng_fillfn(void *unused)
continue;
}
add_hwgenerator_randomness((void *)rng_fillbuf, rc,
- (rc*current_quality)>>10);
+ rc * current_quality * 8 >> 10);
}
hwrng_fill = NULL;
return 0;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

2014-07-28 09:49:35

by Torsten Duwe

Subject: Re: [PATCH] hwrng: Pass entropy to add_hwgenerator_randomness() in bits, not bytes

On Fri, Jul 25, 2014 at 03:19:18PM -0700, Stephen Boyd wrote:
> rng_get_data() returns the number of bytes read from the hardware.
> The entropy argument to add_hwgenerator_randomness() is passed
> directly to credit_entropy_bits() so we should be passing the
> number of bits, not bytes here.

Absolutely correct.

Acked-by: Torsten Duwe <[email protected]>

> Fixes: be4000bc464 "hwrng: create filler thread"
> Cc: Torsten Duwe <[email protected]>
> Signed-off-by: Stephen Boyd <[email protected]>
> ---
> drivers/char/hw_random/core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
> index dc80cdab733d..6e02ec103cc7 100644
> --- a/drivers/char/hw_random/core.c
> +++ b/drivers/char/hw_random/core.c
> @@ -362,7 +362,7 @@ static int hwrng_fillfn(void *unused)
> continue;
> }
> add_hwgenerator_randomness((void *)rng_fillbuf, rc,
> - (rc*current_quality)>>10);
> + rc * current_quality * 8 >> 10);
> }
> hwrng_fill = NULL;
> return 0;
> --
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> hosted by The Linux Foundation
>
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