From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753396AbZJIJyA (ORCPT ); Fri, 9 Oct 2009 05:54:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751265AbZJIJx7 (ORCPT ); Fri, 9 Oct 2009 05:53:59 -0400 Received: from cantor2.suse.de ([195.135.220.15]:46157 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750980AbZJIJx7 (ORCPT ); Fri, 9 Oct 2009 05:53:59 -0400 Date: Fri, 9 Oct 2009 11:53:21 +0200 (CEST) From: Jiri Kosina X-X-Sender: jkosina@wotan.suse.de To: Geert Uytterhoeven , Tejun Heo , Jens Axboe Cc: linux-kernel@vger.kernel.org Subject: [PATCH] [RFC] ataflop: remove buggy IRQ disable from do_fd_request() Message-ID: User-Agent: Alpine 2.00 (LSU 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There is a nice gem in drivers/block/ataflop.c::do_fd_request() void do_fd_request(struct request_queue * q) { unsigned long flags; DPRINT(("do_fd_request for pid %d\n",current->pid)); while( fdc_busy ) sleep_on( &fdc_wait ); fdc_busy = 1; stdma_lock(floppy_irq, NULL); atari_disable_irq( IRQ_MFP_FDC ); local_save_flags(flags); /* The request function is called with ints local_irq_disable(); * disabled... so must save the IPL for later */ redo_fd_request(); local_irq_restore(flags); atari_enable_irq( IRQ_MFP_FDC ); } If you look at the code long enough, you will notioce that the local_irq_disable() call is actually commented out. This has been introduced back in 2002 in [1], but as you can see, the same bug has been there even before, with the sti() call being commented out in the very same way :) I am not familiar with the code myself at all, but I guess that the whole stuff can just be removed. Why do we need save_flags/restore_flags at all, without actually disabling the local IRQs afterwards? The redo_fd_request() doesn't seem to do anything that would mess with flags inconsistently. But I'd rather anyone who has touched the surrounding code in past years Ack it. I can then take it through trivial tree or submit to akpm. [1] http://lkml.org/lkml/2002/12/27/58 Signed-off-by: Jiri Kosina --- drivers/block/ataflop.c | 3 --- 1 files changed, 0 insertions(+), 3 deletions(-) diff --git a/drivers/block/ataflop.c b/drivers/block/ataflop.c index 847a9e5..a5af1d6 100644 --- a/drivers/block/ataflop.c +++ b/drivers/block/ataflop.c @@ -1478,10 +1478,7 @@ void do_fd_request(struct request_queue * q) stdma_lock(floppy_irq, NULL); atari_disable_irq( IRQ_MFP_FDC ); - local_save_flags(flags); /* The request function is called with ints - local_irq_disable(); * disabled... so must save the IPL for later */ redo_fd_request(); - local_irq_restore(flags); atari_enable_irq( IRQ_MFP_FDC ); } -- 1.5.6