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From: David Howells <dhowells@redhat.com>
To: Hillf Danton <hdanton@sina.com>
Cc: dhowells@redhat.com, viro@zeniv.linux.org.uk,
	Casey Schaufler <casey@schaufler-ca.com>,
	Stephen Smalley <sds@tycho.nsa.gov>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	nicolas.dichtel@6wind.com, raven@themaw.net,
	Christian Brauner <christian@brauner.io>,
	keyrings@vger.kernel.org, linux-usb@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 04/11] General notification queue with user mmap()'able ring buffer [ver #7]
Date: Tue, 03 Sep 2019 17:37:10 +0100	[thread overview]
Message-ID: <27533.1567528630@warthog.procyon.org.uk> (raw)
In-Reply-To: <20190903085706.7700-1-hdanton@sina.com>

Hillf Danton <hdanton@sina.com> wrote:

> > +	for (i = 0; i < wf->nr_filters; i++) {
> > +		wt = &wf->filters[i];
> > +		if (n->type == wt->type &&
> > +		    (wt->subtype_filter[n->subtype >> 5] &
> > +		     (1U << (n->subtype & 31))) &&
> 
> Replace the pure numbers with something easier to understand.

How about the following:

static bool filter_watch_notification(const struct watch_filter *wf,
				      const struct watch_notification *n)
{
	const struct watch_type_filter *wt;
	unsigned int st_bits = sizeof(wt->subtype_filter[0]) * 8;
	unsigned int st_index = n->subtype / st_bits;
	unsigned int st_bit = 1U << (n->subtype % st_bits);
	int i;

	if (!test_bit(n->type, wf->type_filter))
		return false;

	for (i = 0; i < wf->nr_filters; i++) {
		wt = &wf->filters[i];
		if (n->type == wt->type &&
		    (wt->subtype_filter[st_index] & st_bit) &&
		    (n->info & wt->info_mask) == wt->info_filter)
			return true;
	}

	return false; /* If there is a filter, the default is to reject. */
}

David

      parent reply	other threads:[~2019-09-03 16:37 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20190903085706.7700-1-hdanton@sina.com>
2019-08-30 13:57 ` [PATCH 00/11] Keyrings, Block and USB notifications [ver #7] David Howells
2019-08-30 13:57   ` [PATCH 01/11] uapi: General notification ring definitions " David Howells
2019-08-30 13:57   ` [PATCH 02/11] security: Add hooks to rule on setting a watch " David Howells
2019-08-30 13:57   ` [PATCH 03/11] security: Add a hook for the point of notification insertion " David Howells
2019-08-30 13:57   ` [PATCH 04/11] General notification queue with user mmap()'able ring buffer " David Howells
2019-08-30 13:57   ` [PATCH 05/11] keys: Add a notification facility " David Howells
2019-08-30 13:58   ` [PATCH 06/11] Add a general, global device notification watch list " David Howells
2019-09-03  8:34     ` Yoshihiro Shimoda
2019-09-03 16:41     ` David Howells
2019-08-30 13:58   ` [PATCH 07/11] block: Add block layer notifications " David Howells
2019-08-30 13:58   ` [PATCH 08/11] usb: Add USB subsystem " David Howells
2019-09-03  8:53     ` Yoshihiro Shimoda
2019-09-03  9:37       ` Greg Kroah-Hartman
2019-09-04  1:53         ` Yoshihiro Shimoda
2019-09-03 12:51     ` Guenter Roeck
2019-09-03 16:07     ` David Howells
2019-09-03 16:12       ` Guenter Roeck
2019-09-03 16:29       ` David Howells
2019-09-03 17:06         ` Alan Stern
2019-09-03 17:17           ` Alan Stern
2019-09-04 15:17             ` David Howells
2019-08-30 13:58   ` [PATCH 09/11] Add sample notification program " David Howells
2019-08-30 13:58   ` [PATCH 10/11] selinux: Implement the watch_key security hook " David Howells
2019-08-30 14:15     ` Stephen Smalley
2019-08-30 14:23     ` David Howells
2019-08-30 14:41     ` David Howells
2019-08-30 15:41       ` Stephen Smalley
2019-08-30 13:58   ` [PATCH 11/11] smack: Implement the watch_key and post_notification hooks [untested] " David Howells
2019-09-03 15:20     ` Casey Schaufler
2019-09-03 15:41     ` David Howells
2019-09-03 17:40       ` Casey Schaufler
2019-09-03 18:06       ` David Howells
2019-09-03 22:16         ` Casey Schaufler
2019-09-03 22:39         ` David Howells
2019-09-04 12:08         ` David Howells
2019-09-04 14:56           ` Casey Schaufler
2019-08-30 14:15   ` watch_queue(7) manpage David Howells
2019-08-30 14:15   ` watch_devices(2) manpage David Howells
2019-08-30 14:16   ` keyctl_watch_key.3 manpage David Howells
2019-08-30 22:09   ` [PATCH 00/11] Keyrings, Block and USB notifications [ver #7] Casey Schaufler
2019-09-02 12:39   ` David Howells
2019-09-02 13:26   ` David Howells
2019-09-03 16:06   ` [PATCH 04/11] General notification queue with user mmap()'able ring buffer " David Howells
2019-09-03 16:37   ` David Howells [this message]

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