From: PrasannaKumar Muralidharan Subject: Re: [PATCH 3/3] crypto: hwrng add sysfs attribute to show user selected rng Date: Mon, 10 Jul 2017 11:49:16 +0530 Message-ID: References: <1499076204-18547-1-git-send-email-freude@linux.vnet.ibm.com> <1499076204-18547-4-git-send-email-freude@linux.vnet.ibm.com> <0954fe1d-e0ff-6b35-6d2d-96901cad6503@linux.vnet.ibm.com> <2cfcef13-2315-6bbe-4eda-ee019c870ce8@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: linux-crypto@vger.kernel.org, Herbert Xu , Arnd Bergmann , Greg KH , schwidefsky@de.ibm.com To: Harald Freudenberger Return-path: Received: from mail-vk0-f68.google.com ([209.85.213.68]:33954 "EHLO mail-vk0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751147AbdGJGTS (ORCPT ); Mon, 10 Jul 2017 02:19:18 -0400 Received: by mail-vk0-f68.google.com with SMTP id 191so5570802vko.1 for ; Sun, 09 Jul 2017 23:19:18 -0700 (PDT) In-Reply-To: <2cfcef13-2315-6bbe-4eda-ee019c870ce8@linux.vnet.ibm.com> Sender: linux-crypto-owner@vger.kernel.org List-ID: Hi Harald, > Hello PrasannaKumar > > here is now a version which combines patch 2 and patch 3 together > according to your suggestions: > > ========== cut ========== > > From: Harald Freudenberger > Date: Fri, 30 Jun 2017 17:06:40 +0200 > Subject: [PATCH 2/2] crypto: hwrng remember rng chosen by user > > When a user chooses a rng source via sysfs attribute > this rng should be sticky, even when other sources > with better quality to register. This patch introduces > a simple way to remember the user's choice. This is > reflected by a new sysfs attribute file 'rng_selected' > which shows if the current rng has been chosen by > userspace. The new attribute file shows '1' for user > selected rng and '0' otherwise. > > Signed-off-by: Harald Freudenberger > --- > drivers/char/hw_random/core.c | 21 +++++++++++++++++++-- > 1 file changed, 19 insertions(+), 2 deletions(-) > > diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c > index e9dda16..9701ac7 100644 > --- a/drivers/char/hw_random/core.c > +++ b/drivers/char/hw_random/core.c > @@ -28,6 +28,8 @@ > #define RNG_MODULE_NAME "hw_random" > > static struct hwrng *current_rng; > +/* the current rng has been explicitly chosen by user via sysfs */ > +static int cur_rng_set_by_user; > static struct task_struct *hwrng_fill; > /* list of registered rngs, sorted decending by quality */ > static LIST_HEAD(rng_list); > @@ -304,6 +306,7 @@ static ssize_t hwrng_attr_current_store(struct device *dev, > list_for_each_entry(rng, &rng_list, list) { > if (sysfs_streq(rng->name, buf)) { > err = 0; > + cur_rng_set_by_user = 1; > if (rng != current_rng) > err = set_current_rng(rng); > break; > @@ -352,16 +355,27 @@ static ssize_t hwrng_attr_available_show(struct device *dev, > return strlen(buf); > } > > +static ssize_t hwrng_attr_selected_show(struct device *dev, > + struct device_attribute *attr, > + char *buf) > +{ > + return snprintf(buf, PAGE_SIZE, "%d\n", cur_rng_set_by_user); > +} > + > static DEVICE_ATTR(rng_current, S_IRUGO | S_IWUSR, > hwrng_attr_current_show, > hwrng_attr_current_store); > static DEVICE_ATTR(rng_available, S_IRUGO, > hwrng_attr_available_show, > NULL); > +static DEVICE_ATTR(rng_selected, S_IRUGO, > + hwrng_attr_selected_show, > + NULL); > > static struct attribute *rng_dev_attrs[] = { > &dev_attr_rng_current.attr, > &dev_attr_rng_available.attr, > + &dev_attr_rng_selected.attr, > NULL > }; > > @@ -444,10 +458,12 @@ int hwrng_register(struct hwrng *rng) > > old_rng = current_rng; > err = 0; > - if (!old_rng || (rng->quality > old_rng->quality)) { > + if (!old_rng || > + (!cur_rng_set_by_user && rng->quality > old_rng->quality)) { > /* > * Set new rng as current as the new rng source > - * provides better entropy quality. > + * provides better entropy quality and was not > + * chosen by userspace. > */ > err = set_current_rng(rng); > if (err) > @@ -479,6 +495,7 @@ void hwrng_unregister(struct hwrng *rng) > list_del(&rng->list); > if (current_rng == rng) { > drop_current_rng(); > + cur_rng_set_by_user = 0; > /* rng_list is sorted by quality, use the best (=first) one */ > if (!list_empty(&rng_list)) { > struct hwrng *new_rng; > -- > 2.7.4 > > ========== cut ========== > Good work, patch looks good to me. Reviewed-by: PrasannaKumar Muralidharan . I am wondering if you want to make a v2 of the whole series. You can just put your patch 1 and 2 and send it again with description. Requiring a v2 depends on how Herbert prefers to take patches in. Herbert, Do you prefer a v2 of the patch series or you can take this version of patch 2? Note: If you are re-posting this patch as v2 please add my reviewed by tag for both the patches. Regards, PrasannaKumar