From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753869AbYIPLbV (ORCPT ); Tue, 16 Sep 2008 07:31:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752640AbYIPLbI (ORCPT ); Tue, 16 Sep 2008 07:31:08 -0400 Received: from ti-out-0910.google.com ([209.85.142.184]:26710 "EHLO ti-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752634AbYIPLbH (ORCPT ); Tue, 16 Sep 2008 07:31:07 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=xE9aeh/F+0LGKsuXmFsQ4thyXUCrKhyfnxvQ/6O0Ypf7EY3y4GkUlUEXgB2G/AxdMA WhD3oQWAy/Q2NLrW3FKY/gDARC+d+XLxs4rC2xUZJU1utRm9XQETw5QApfSI8FEvzhM1 fNYktxVZGjze1ErCYp/sDWzrzBAME3pPp8eN0= Message-ID: Date: Tue, 16 Sep 2008 17:01:04 +0530 From: "Manish Katiyar" To: "Marco Stornelli" Subject: Re: [PATCH] vfs: added better file aio_read aio_write operations presence check Cc: viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <48CF94DE.7020209@coritel.it> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <48CF7C85.1070309@coritel.it> <48CF94DE.7020209@coritel.it> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 16, 2008 at 4:43 PM, Marco Stornelli wrote: > BUG_ON it was a way to say: "hey you've used the do_sync_read/write as > read/write operation but you don't specified an aio_read/write", but > your solutions it's good too. Looks like I made some copy paste error while sending the patch. Below is the updated one. Signed-off-by: Manish Katiyar --- fs/read_write.c | 10 ++++++++-- 1 files changed, 8 insertions(+), 2 deletions(-) diff --git a/fs/read_write.c b/fs/read_write.c index 9ba495d..b89b707 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -225,7 +225,10 @@ ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *pp kiocb.ki_left = len; for (;;) { - ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos); + if (filp->f_op->aio_read) + ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos); + else + ret = generic_file_aio_read(&kiocb, &iov, 1, kiocb.ki_pos); if (ret != -EIOCBRETRY) break; wait_on_retry_sync_kiocb(&kiocb); @@ -280,7 +283,10 @@ ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, lof kiocb.ki_left = len; for (;;) { - ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos); + if (filp->f_op->aio_write) + ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos); + else + ret = generic_file_aio_write(&kiocb, &iov, 1, kiocb.ki_pos); if (ret != -EIOCBRETRY) break; wait_on_retry_sync_kiocb(&kiocb); -- 1.5.4.3 Thanks - Manish > > Manish Katiyar ha scritto: >> On Tue, Sep 16, 2008 at 2:59 PM, Marco Stornelli >> wrote: >>> From: Marco Stornelli >>> >>> If a filesystem in the file operations specifies for read and write operations only do_sync_read and do_sync_write without >>> init aio_read and aio_write, there will be a kernel oops, because the vfs code check the presence of (to read for example) >>> read OR aio_read method, then it calls read if it's pointer is not null. It's not sufficient because if the read function is >>> actually a do_sync_read, it calls aio_read but without checking the presence. I think a BUG_ON check can be more useful. >> >> Instead of doing a BUG_ON() why can't we simply fall back to the >> generic_aio functions since most of the fs tend to do so as below. >> >> >> Signed-off-by: Manish Katiyar >> >> --- >> fs/read_write.c | 10 ++++++++-- >> 1 files changed, 8 insertions(+), 2 deletions(-) >> >> diff --git a/fs/read_write.c b/fs/read_write.c >> index 9ba495d..5439bc4 100644 >> --- a/fs/read_write.c >> +++ b/fs/read_write.c >> @@ -225,7 +225,11 @@ ssize_t do_sync_read(struct file *filp, char >> __user *buf, size_t len, loff_t *pp >> kiocb.ki_left = len; >> >> for (;;) { >> - ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos); >> + if (filp->f_op->aio_read) >> + ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos); >> + else >> + ret = generic_file_aio_read(&kiocb, &iov, 1, kiocb.ki_pos); >> if (ret != -EIOCBRETRY) >> break; >> wait_on_retry_sync_kiocb(&kiocb); >> @@ -280,7 +284,10 @@ ssize_t do_sync_write(struct file *filp, const >> char __user *buf, size_t len, lof >> kiocb.ki_left = len; >> >> for (;;) { >> - ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos); >> + if (filp->f_op->aio_write) >> + ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos); >> + else >> + ret = generic_file_aio_write(&kiocb, &iov, 1, kiocb.ki_pos); >> if (ret != -EIOCBRETRY) >> break; >> wait_on_retry_sync_kiocb(&kiocb); > >