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Subject[PATCH] [RFC] ataflop: remove buggy 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.

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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