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authorJiri Kosina <jkosina@suse.cz>2009-10-09 11:49:10 +0200
committerJiri Kosina <jkosina@suse.cz>2009-11-09 09:40:57 +0100
commite0c0978699a83f26f2341f7eedc1463b79e31aff (patch)
tree20bc35c264eef530f27dbb6529160d41a2f80959 /drivers/block
parent7a7236e0f3f836439442e9161dd6d25fde7ca259 (diff)
downloadblackbird-op-linux-e0c0978699a83f26f2341f7eedc1463b79e31aff.tar.gz
blackbird-op-linux-e0c0978699a83f26f2341f7eedc1463b79e31aff.zip
ataflop: remove buggy/commented-out IRQ disable from do_fd_request()
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. [1] http://lkml.org/lkml/2002/12/27/58 Jens: That does look odd. The comment is correct that the function is entered with interrupts disabled (and the queue lock held). So I'd say your patch looks fine, the whole save/restore business looks meaningless. Signed-off-by: Jiri Kosina <jkosina@suse.cz> Acked-by: Jens Axboe <jens.axboe@oracle.com> Acked-by: Michael Schmitz <schmitz@biophys.uni-duesseldorf.de>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/ataflop.c3
1 files changed, 0 insertions, 3 deletions
diff --git a/drivers/block/ataflop.c b/drivers/block/ataflop.c
index 847a9e57570a..a5af1d6dda8b 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 );
}
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