On Thu, Oct 16, 2014 at 10:25:03AM -0700, Joe Perches wrote: > On Thu, 2014-10-16 at 19:15 +0200, Rickard Strandqvist wrote: > > The buf is used to hold the list of hwrng devices registered. > > The old code ensures we don't walk off the end of buf as we > > fill it, but it's unnecessarily complicated and thus difficult > > to maintain. Simplify it by using strlcat. > > We also ensure the string within buf is NULL terminated > > so the final strlen is ok. > [] > > diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c > [] > > @@ -289,16 +288,13 @@ static ssize_t hwrng_attr_available_show(struct > > device *dev, > > return -ERESTARTSYS; > > buf[0] = '\0'; > > list_for_each_entry(rng, &rng_list, list) { > > - strncat(buf, rng->name, PAGE_SIZE - ret - 1); > > - ret += strlen(rng->name); > > - strncat(buf, " ", PAGE_SIZE - ret - 1); > > - ret++; > > + strlcat(buf, rng->name, PAGE_SIZE); > > + strlcat(buf, " ", PAGE_SIZE); > > } > > - strncat(buf, "\n", PAGE_SIZE - ret - 1); > > - ret++; > > + strlcat(buf, "\n", PAGE_SIZE); > > mutex_unlock(&rng_mutex); > > > > - return ret; > > + return strlen(buf); > > } > > > > static DEVICE_ATTR(rng_current, S_IRUGO | S_IWUSR, > > Rickard, can you please use some optimizations here > (and elsewhere) so that strlcat doesn't always have > to strlen the first string and the return doesn't > have to do the strlen too?
Joe, is further optimization worth the effort? This function is only called when the end user reads the sysfs file rng_available... thx, Jason. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/