3w-9xxx: don't unmap bounce buffered commands
3w-9xxx: don't unmap bounce buffered commands

3w controller don't dma map small single SGL entry commands but instead
bounce buffer them.  Add a helper to identify these commands and don't
call scsi_dma_unmap for them.

Based on an earlier patch from James Bottomley.

Fixes: 118c85 ("3w-9xxx: fix command completion race")
Reported-by: Tóth Attila <dcaf18b342299d0ae9e847224021f74b7025b802@atoth.sote.hu>
Tested-by: Tóth Attila <dcaf18b342299d0ae9e847224021f74b7025b802@atoth.sote.hu>
Signed-off-by: Christoph Hellwig <923f7720577207a44b32e59bbfbea59d27f1ae8e@lst.de>
Acked-by: Adam Radford <3dbf2d2fbfb3484492c697dc4586b54d94b4a311@gmail.com>
Signed-off-by: James Bottomley <1acebbdca565c7b6b638bdc23b58b5610d1a56b8@Odin.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs