Make the queue depth of loop devices identical to that of the underlying
storage device. This patch reduces latency by lowering the queue depth.
With this patch applied I see the following:
# cat /sys/block/loop30/queue/nr_requests
32
Bug: 194450129
Test: Built Android images, installed these and verified that the queue depth of loop devices is 32 instead of 256.
Merged-In: Ifa16084c7df3a54d9559c2388abc4a8392ff88c6
Change-Id: Icc89e1f88d2f0ade2805999afef556b15b7ff8eb
Ignore-AOSP-First: Already in AOSP.
Signed-off-by: Bart Van Assche <bvanassche@google.com>
