From: Felix Fietkau <nbd@openwrt.org>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: Ben Greear <greearb@candelatech.com>, linux-wireless@vger.kernel.org
Subject: Re: [PATCH v2] wireless: Allow registering more than one beacon listener.
Date: Mon, 29 Oct 2012 17:54:01 +0100 [thread overview]
Message-ID: <508EB4A9.2040203@openwrt.org> (raw)
In-Reply-To: <1351527990.10925.35.camel@jlt4.sipsolutions.net>
On 2012-10-29 5:26 PM, Johannes Berg wrote:
> On Mon, 2012-10-29 at 09:17 -0700, Ben Greear wrote:
>
>> >> + spin_lock_bh(&rdev->beacon_registrations_lock);
>> > ...
>> >> + spin_unlock_bh(&rdev->beacon_registrations_lock);
>> >
>> > I have a feeling this is incorrect, this is called with BHs disabled, so
>> > if we disable/enable BHs here we end up with BHs enabled even if the
>> > caller wanted them disabled, no?
>> >
>> > So I suppose unless we need to be able to call this from hard interrupt
>> > in some driver (unlikely) we should add a change like this:
>>
>> I get confused with the various types of spin-locks,
>> and I just copied this code from the mgt frames logic.
>
> Uh, that looks like a bug there as well then?
As far as I know, local_bh_enable/local_bh_disable (which are used by
spin_lock_bh) are re-entrant. Using them from a BH-disabled context is
safe. All I can find with a few simple google searches confirms this.
- Felix
next prev parent reply other threads:[~2012-10-29 16:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-26 21:49 [PATCH v2] wireless: Allow registering more than one beacon listener greearb
2012-10-29 9:04 ` Johannes Berg
2012-10-29 16:17 ` Ben Greear
2012-10-29 16:26 ` Johannes Berg
2012-10-29 16:54 ` Felix Fietkau [this message]
2012-11-05 15:32 ` Johannes Berg
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=508EB4A9.2040203@openwrt.org \
--to=nbd@openwrt.org \
--cc=greearb@candelatech.com \
--cc=johannes@sipsolutions.net \
--cc=linux-wireless@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).