From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756241Ab1DKWMu (ORCPT ); Mon, 11 Apr 2011 18:12:50 -0400 Received: from mail-qw0-f46.google.com ([209.85.216.46]:34181 "EHLO mail-qw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755356Ab1DKWMs convert rfc822-to-8bit (ORCPT ); Mon, 11 Apr 2011 18:12:48 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=hjMtKTOpWlvElAt/L/Rkw6+08hb2GJ1Z0fcbYHNW9PMcO+YENxIMVkx4VwhTsOA0gI Vz4emjH+m/mfo1FrwTARO3F9kY9QATxlgtDOzP/iqlZPsyYXF1dR01B6FkHFIlrnSJQT aUeaN0OTIBepjR7fayPEWyOnlWvTza299fau0= MIME-Version: 1.0 In-Reply-To: <20110411215619.GA27943@kroah.com> References: <1302557114-7880-1-git-send-email-zajec5@gmail.com> <20110411210631.GA28559@kroah.com> <20110411212513.GA17809@kroah.com> <20110411215619.GA27943@kroah.com> Date: Tue, 12 Apr 2011 00:12:47 +0200 Message-ID: Subject: Re: [RFC][PATCH V3] axi: add AXI bus driver From: =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= To: Greg KH Cc: linux-wireless@vger.kernel.org, "John W. Linville" , George Kashperko , Arnd Bergmann , Russell King , "linux-kernel@vger.kernel.org" , b43-dev@lists.infradead.org, =?UTF-8?Q?Michael_B=C3=BCsch?= , linuxdriverproject , Andy Botting , "linux-arm-kernel@lists.infradead.org" , Larry Finger Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2011/4/11 Greg KH : > On Mon, Apr 11, 2011 at 11:36:39PM +0200, Rafał Miłecki wrote: >> 2011/4/11 Greg KH : >> > Please read the documentation for how to do this properly.  I find it >> > really hard to believe that you wrote that comment instead of putting in >> > the 2 lines of code required for this function. >> > >> > Especially as-it-is, your code does not work properly and leaks memory >> > badly.  Why would you do that on purpose? >> >> I tried to read some documentation about this. >> >> 1) driver-mode/device.txt says only that: >> > Callback to free the device after all references have >> > gone away. This should be set by the allocator of the >> > device (i.e. the bus driver that discovered the device). >> I *really* do not know how my driver should "free" core on AXI bus. > > The structure that you have created, added to the bus, is now ready to > have its memory freed.  So free it. > > This usually means something like: >        struct my_obj = to_my_obj(dev); >        kfree(my_obj); > in the release function. I register core->dev to the bus (I set core->dev.bus and core->dev.parent, is that what you mean?). This core->dev is "struct dev" embedded in "struct axi_device". By embedded I mean it is *not* a pointer, I do not alloc it, it's part of the "struct axi_device". >> 2) LDD3 says: >> > The method is called when the last reference to the device is removed; it is called >> > from the embedded kobject’s release method. All device structures registered with >> > the core must have a release method, or the kernel prints out scary complaints. >> Well, I do not register any structs for AXI core. > > Yes you did, otherwise you would have never seen that callback warning > you that you needed a release function. I was thinking about alloc, sorry, ignore this one. >> 4) SSB in it's ssb_release_dev just calls kfree on struct that was >> allocated when registering drivers. *I do not* allocate such a struct, >> so I believe I do exactly the same memory leak as SSB does. > > Well someone allocated it, right?  Who did it?  If it wasn't you, where > did that structure come from and why are you registering it on your bus? > >> Can you spend 2 more minues in addition to commenting my ideas and >> help me with writing that 2 lines I missed? Where do I leak memory in >> my driver? Which struct should I kfree? > > The structure that you wrap around 'struct device' for your bus. As explained above, this I do not dynamically alloc this 'struct device'. So is there really any memory leak? -- Rafał