block: add comment on why we save and disable interrupts in flush_plug_list()
block: add comment on why we save and disable interrupts in flush_plug_list()

It's done at the top to avoid doing it for every queue we unplug.

Signed-off-by: Jens Axboe <08e836a620179c237f631ad0545a7ebdf54201f3@fusionio.com>

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