On Mon, Oct 20, 2014 at 10:42:11AM +1030, Rusty Russell wrote: > Amos Kong <akong@xxxxxxxxxx> writes: > > We got a warning in boot stage when above set_current_rng() is executed, > > it can be fixed by init rng->ref in hwrng_init(). > > > > > > @@ -166,6 +169,8 @@ static inline int hwrng_init(struct hwrng *rng) > > if (current_quality > 0 && !hwrng_fill) > > start_khwrngd(); > > > > + kref_init(&rng->ref); > > + > > return 0; > > } > > OK, I folded this fix on. Thanks. Reviewed-by: Amos Kong <akong@xxxxxxxxxx> > Thanks, > Rusty. > > hw_random: use reference counts on each struct hwrng. > > current_rng holds one reference, and we bump it every time we want > to do a read from it. > > This means we only hold the rng_mutex to grab or drop a reference, > so accessing /sys/devices/virtual/misc/hw_random/rng_current doesn't > block on read of /dev/hwrng. > > Using a kref is overkill (we're always under the rng_mutex), but > a standard pattern. > > This also solves the problem that the hwrng_fillfn thread was > accessing current_rng without a lock, which could change (eg. to NULL) > underneath it. > > v3: initialize kref (thanks Amos Kong) > v2: fix missing put_rng() on exit path (thanks Amos Kong) > Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx> > > diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c > index a0905c818e13..0ecac38da954 100644 > --- a/drivers/char/hw_random/core.c > +++ b/drivers/char/hw_random/core.c .... -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
