All of lore.kernel.org
 help / color / mirror / Atom feed
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: noman pouigt <variksla@gmail.com>
Cc: rostedt@goodmis.org, rusty@rustcorp.com.au,
	gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org
Subject: Re: atomic read and increment question
Date: Tue, 18 Mar 2014 05:52:56 -0700	[thread overview]
Message-ID: <20140318125256.GJ4420@linux.vnet.ibm.com> (raw)
In-Reply-To: <CAES_P+-FDQKQSSSdJBY0ivGJtHOA6K4rYSy7z20HowUUVcHdJQ@mail.gmail.com>

On Tue, Mar 18, 2014 at 01:26:12AM -0700, noman pouigt wrote:
> Hello,
> 
> I looked through the documentation for atomic
> operations but couldn't find out the api for following
> operation:
> 
> x = 1;
> temp = atomic_read_increment(x);
> 
> so basically this will read the old value of x in temp
> and then increment x.
> 
> so temp = 1 and x = 2.
> 
> Is this api already available?

You want atomic_inc_return().  It returns the new value rather than the
old value, but you can do the following:

	temp = atomic_inc_return(&x) - 1;

							Thanx, Paul


      parent reply	other threads:[~2014-03-18 12:53 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-18  8:26 atomic read and increment question noman pouigt
2014-03-18 11:10 ` Clemens Ladisch
2014-03-18 12:52 ` Paul E. McKenney [this message]

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=20140318125256.GJ4420@linux.vnet.ibm.com \
    --to=paulmck@linux.vnet.ibm.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=rostedt@goodmis.org \
    --cc=rusty@rustcorp.com.au \
    --cc=variksla@gmail.com \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.