From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Matti Linnanvuori" Subject: Re: [PATCH v1.2.26] wan: new driver retina Date: Sun, 1 Jun 2008 08:59:55 +0300 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: "Krzysztof Halasa" Return-path: Received: from wf-out-1314.google.com ([209.85.200.174]:12811 "EHLO wf-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751520AbYFAF74 (ORCPT ); Sun, 1 Jun 2008 01:59:56 -0400 Received: by wf-out-1314.google.com with SMTP id 27so421208wfd.4 for ; Sat, 31 May 2008 22:59:55 -0700 (PDT) In-Reply-To: Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: 2008/5/30 Krzysztof Halasa : > "Matti Linnanvuori" writes: >>>> +static int fepci_char_open(struct inode *inode, struct file *filp) >>>> +{ >>>> + unsigned int minor = MINOR(inode->i_rdev); >>>> + if (unlikely(minor >= find_cnt || card_privates[minor].pci_dev == NULL)) >>>> + return -ENXIO; >>>> + filp->f_op = &fepci_char_fops; >>>> + if (unlikely(!try_module_get(THIS_MODULE))) >>>> + return -EBUSY; >>> >>> That won't work race-free, use owner field. >> >> You mean the f_op assignment? I have removed that. > > Actually I meant try_module_get() from within the driver, for example > your module may get unloaded while in this function, before this > try_module_get(), and that would be fatal. I don't think the module can finish getting unloaded while in that function because the module cleanup function unregisters the character device. > Yes, I thought stream mode = character device but now I see it's > another flavour of network device(?), which is never up and exists > only for the ability to receive netdev ioctls (though it also uses > char dev ioctls). > > Did I get this right? Yeah. > Why not simply use a character device, with normal read, write etc? It would make more sense to use a character device. Read and write system calls consume more CPU time, though.