On Tue, 15 May 2018 13:06:25 +1000 "Tobin C. Harding" <[email protected]> wrote:
> Currently the function get_random_bytes_arch() has return value 'void'. > If the hw RNG fails we currently fall back to using get_random_bytes(). > This defeats the purpose of requesting random material from the hw RNG > in the first place. > > There are currently no intree users of get_random_bytes_arch(). > > Only get random bytes from the hw RNG, make function return the number > of bytes retrieved from the hw RNG. > > Signed-off-by: Tobin C. Harding <[email protected]> > Acked-by: Theodore Ts'o <[email protected]> > Signed-off-by: Tobin C. Harding <[email protected]> > --- > drivers/char/random.c | 16 +++++++++------- > include/linux/random.h | 2 +- > 2 files changed, 10 insertions(+), 8 deletions(-) > > diff --git a/drivers/char/random.c b/drivers/char/random.c > index 031d18b31e0f..4b0ec597e783 100644 > --- a/drivers/char/random.c > +++ b/drivers/char/random.c > @@ -1725,26 +1725,28 @@ EXPORT_SYMBOL(del_random_ready_callback); > * key known by the NSA). So it's useful if we need the speed, but > * only if we're willing to trust the hardware manufacturer not to > * have put in a back door. > + * > + * Return number of bytes filled in. > */ > -void get_random_bytes_arch(void *buf, int nbytes) > +int __must_check get_random_bytes_arch(void *buf, int nbytes) > { > char *p = buf; > + int left = nbytes; Just a nit, but I know some kernel devs prefer "upside-down-xmas-tree" style of declarations. Which would make the above: int left = nbytes; char *p = buf; > > - trace_get_random_bytes_arch(nbytes, _RET_IP_); > - while (nbytes) { > + trace_get_random_bytes_arch(left, _RET_IP_); Nothing to do with this patch series, but I wonder if we should move the trace event below, and record how much was done. > + while (left) { > unsigned long v; > - int chunk = min(nbytes, (int)sizeof(unsigned long)); > + int chunk = min_t(int, left, (int)sizeof(unsigned long)); > > if (!arch_get_random_long(&v)) > break; > > memcpy(p, &v, chunk); > p += chunk; > - nbytes -= chunk; > + left -= chunk; > } > > - if (nbytes) > - get_random_bytes(p, nbytes); > + return nbytes - left; > } > EXPORT_SYMBOL(get_random_bytes_arch); > > diff --git a/include/linux/random.h b/include/linux/random.h > index 2ddf13b4281e..f1c9bc5cd231 100644 > --- a/include/linux/random.h > +++ b/include/linux/random.h > @@ -38,7 +38,7 @@ extern void get_random_bytes(void *buf, int nbytes); > extern int wait_for_random_bytes(void); > extern int add_random_ready_callback(struct random_ready_callback *rdy); > extern void del_random_ready_callback(struct random_ready_callback *rdy); > -extern void get_random_bytes_arch(void *buf, int nbytes); > +extern int __must_check get_random_bytes_arch(void *buf, int nbytes); > > #ifndef MODULE > extern const struct file_operations random_fops, urandom_fops; Other than that... Reviewed-by: Steven Rostedt (VMware) <[email protected]> -- Steve
