From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <491A07D4.2020001@redhat.com> Date: Wed, 12 Nov 2008 00:31:48 +0200 From: Izik Eidus MIME-Version: 1.0 Subject: Re: [PATCH 3/4] add ksm kernel shared memory driver References: <1226409701-14831-1-git-send-email-ieidus@redhat.com> <1226409701-14831-2-git-send-email-ieidus@redhat.com> <1226409701-14831-3-git-send-email-ieidus@redhat.com> <1226409701-14831-4-git-send-email-ieidus@redhat.com> <20081111150345.7fff8ff2@bike.lwn.net> <491A0483.3010504@redhat.com> <20081111152527.3c55bd6d@bike.lwn.net> In-Reply-To: <20081111152527.3c55bd6d@bike.lwn.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Jonathan Corbet Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org, aarcange@redhat.com, chrisw@redhat.com, avi@redhat.com List-ID: Jonathan Corbet wrote: > On Wed, 12 Nov 2008 00:17:39 +0200 > Izik Eidus wrote: > > >>>> +static int ksm_dev_open(struct inode *inode, struct file *filp) >>>> +{ >>>> + try_module_get(THIS_MODULE); >>>> + return 0; >>>> +} >>>> + >>>> +static int ksm_dev_release(struct inode *inode, struct file *filp) >>>> +{ >>>> + module_put(THIS_MODULE); >>>> + return 0; >>>> +} >>>> + >>>> +static struct file_operations ksm_chardev_ops = { >>>> + .open = ksm_dev_open, >>>> + .release = ksm_dev_release, >>>> + .unlocked_ioctl = ksm_dev_ioctl, >>>> + .compat_ioctl = ksm_dev_ioctl, >>>> +}; >>>> >>>> >>> Why do you roll your own module reference counting? Is there a >>> reason you don't just set .owner and let the VFS handle it? >>> >>> >> Yes, I am taking get_task_mm() if the module will be removed before i >> free the mms, things will go wrong >> > > But...if you set .owner, the VFS will do the try_module_get() *before* > calling into your module (as an added bonus, it will actually check the > return value too). Ohhh i see what you mean you are right i had at least needed to check for the return value of try_module_get(), anyway will check this issue for V2. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org