dma_free_coherent() needs irqs enabled (sigh)
commitaa24886e379d2b641c5117e178b15ce1d5d366ba
authorDavid Brownell <david-b@pacbell.net>
Fri, 10 Aug 2007 20:10:27 +0000 (10 13:10 -0700)
committerGreg Kroah-Hartman <gregkh@suse.de>
Fri, 12 Oct 2007 22:03:15 +0000 (12 15:03 -0700)
treec0934ff01f7c7a18ec5f86896735286f413cd06e
parentfa007d8bebc5d812a445c48664b5bcad81f1351c
dma_free_coherent() needs irqs enabled (sigh)

On at least ARM (and I'm told MIPS too) dma_free_coherent() has a newish
call context requirement: unlike its dma_alloc_coherent() sibling, it may
not be called with IRQs disabled.  (This was new behavior on ARM as of late
2005, caused by ARM SMP updates.) This little surprise can be annoyingly
driver-visible.

Since it looks like that restriction won't be removed, this patch changes
the definition of the API to include that requirement.  Also, to help catch
nonportable drivers, it updates the x86 and swiotlb versions to include the
relevant warnings.  (I already observed that it trips on the
bus_reset_tasklet of the new firewire_ohci driver.)

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: David Miller <davem@davemloft.net>
Acked-by: Russell King <rmk@arm.linux.org.uk>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Documentation/DMA-API.txt
arch/x86/kernel/pci-dma_32.c
arch/x86/kernel/pci-dma_64.c
lib/swiotlb.c