Messages in this thread Patch in this message | | | Date | Fri, 9 Oct 2009 11:53:21 +0200 (CEST) | From | Jiri Kosina <> | Subject | [PATCH] [RFC] ataflop: remove buggy IRQ disable from do_fd_request() |
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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 <jkosina@suse.cz>
--- 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
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