At91_mci is abusing dma_free_coherent(), which may not be called with IRQs
disabled. I saw "mkfs.ext3" on an MMC card objecting voluminously as each
write completed:
WARNING: at arch/arm/mm/consistent.c:368 dma_free_coherent+0x2c/0x224()
[<c002726c>] (dump_stack+0x0/0x14) from [<c00387d4>] (warn_on_slowpath+0x4c/0x68)
[<c0038788>] (warn_on_slowpath+0x0/0x68) from [<c0028768>] (dma_free_coherent+0x2c/0x224)
r6:00008008 r5:ffc06000 r4:00000000
[<c002873c>] (dma_free_coherent+0x0/0x224) from [<c01918ac>] (at91_mci_irq+0x374/0x420)
[<c0191538>] (at91_mci_irq+0x0/0x420) from [<c0065d9c>] (handle_IRQ_event+0x2c/0x6c)
...
This bug has been around for a LONG time. The MM warning is from late
2005, but the driver merged a year later ... so I'm puzzled why nobody
noticed this before now.
The fix involves noting that this buffer shouldn't be DMA-coherent; it's
just used for normal DMA writes. So replace it with standard kmalloc()
buffering and DMA mapping calls.
This is the quickie fix. A better one would not rely on allocating large
bounce buffers. (Note that dma_alloc_coherent could have failed too, but
that case was ignored... kmalloc is a bit more likely to fail though.)
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Pierre Ossman <drzeus-mmc@drzeus.cx>
Cc: Andrew Victor <linux@maxim.org.za>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
e385ea63f4