[PATCH] libata: don't initialize sg in ata_exec_internal() if DMA_NONE (take #2)
[PATCH] libata: don't initialize sg in ata_exec_internal() if DMA_NONE (take #2)

Calling sg_init_one() with NULL buf causes oops on certain
configurations.  Don't initialize sg in ata_exec_internal() if
DMA_NONE and make the function complain if @buf is NULL when dma_dir
isn't DMA_NONE.  While at it, fix comment.

The problem is discovered and initial patch was submitted by Arnd
Bergmann.

Signed-off-by: Tejun Heo <ccfba69985e72fbcd9ba8bbb6db43d42971ad06d@gmail.com>
Cc: Arnd Bergmann <31ce0e01d6a887319e98c2278af71350d5f64c4f@de.ibm.com>
Signed-off-by: Jeff Garzik <f3e731dfa293c7a83119d8aacfa41b5d2d780be9@garzik.org>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas