Commits
Larry Finger committed 46f401c4297
powerpc/pmac: Fix crash in dma-mapping.h with NULL dma_ops
Commit 5657933dbb6e ("treewide: Move dma_ops from struct dev_archdata
into struct device") introduced a crash for macio devices, an example
backtrace being:
kernel BUG at ./include/linux/dma-mapping.h:465!
Oops: Exception in kernel mode, sig: 5 [#1]
...
NIP [c031ddb0] dmam_alloc_coherent+0x74/0x140
LR [c031de70] dmam_alloc_coherent+0x134/0x140
Call Trace:
dmam_alloc_coherent+0x134/0x140 (unreliable)
pata_macio_port_start+0x3c/0x8c
ata_host_start.part.5+0xfc/0x208
ata_host_activate+0x128/0x154
pata_macio_common_init+0x2f0/0x538
pata_macio_attach+0xd8/0x180
macio_device_probe+0x5c/0xec
driver_probe_device+0x21c/0x314
__driver_attach+0xcc/0xd0
bus_for_each_dev+0x68/0xb4
bus_add_driver+0x1dc/0x244
driver_register+0x88/0x130
pata_macio_init+0x5c/0x88
do_one_initcall+0x40/0x170
kernel_init_freeable+0x134/0x1d0
kernel_init+0x18/0x110
ret_from_kernel_thread+0x5c/0x64
This was caused by the device having NULL dma_ops, triggering the
BUG_ON(). Previously the device inherited its dma_ops via the assignment
to dev->ofdev.dev.archdata. However after commit 5657933dbb6e the
dma_ops are moved into dev->ofdev.dev, and so they need to be explicitly
copied.
Fixes: 5657933dbb6e ("treewide: Move dma_ops from struct dev_archdata into struct device")
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[mpe: Rewrite change log, add backtrace]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>