msm: kgsl: Fix policy sysfs implementation

When switching to another governor, the pwrscale kobject will be deleted
and sysfs_create_group fails due to the uninitialized kobj. This patch
deletes the kobject before attaching the file group.

[   36.270044] [<c0134304>] (__kmalloc_track_caller+0x80/0x194) from [<c010a6d0>] (kstrdup+0x2c/0x54)
[   36.270166] [<c010a6d0>] (kstrdup+0x2c/0x54) from [<c019cc98>] (create_dir+0x24/0x204)
[   36.270257] [<c019cc98>] (create_dir+0x24/0x204) from [<c019d154>] (sysfs_create_subdir+0x24/0x2c)
[   36.270318] [<c019d154>] (sysfs_create_subdir+0x24/0x2c) from [<c019e878>] (sysfs_create_group+0x40/0x1d8)
[   36.270441] [<c019e878>] (sysfs_create_group+0x40/0x1d8) from [<c0389e40>] (kgsl_pwrscale_policy_add_files+0x44/0x68)
[   36.270563] [<c0389e40>] (kgsl_pwrscale_policy_add_files+0x44/0x68) from [<c038e714>] (conservative_init+0xc/0x18)
[   36.270654] [<c038e714>] (conservative_init+0xc/0x18) from [<c0389c6c>] (pwrscale_policy_store+0xcc/0x154)
[   36.270776] [<c0389c6c>] (pwrscale_policy_store+0xcc/0x154) from [<c0389a90>] (pwrscale_sysfs_store+0x20/0x2c)
[   36.270868] [<c0389a90>] (pwrscale_sysfs_store+0x20/0x2c) from [<c019b2a4>] (sysfs_write_file+0x168/0x198)
[   36.270990] [<c019b2a4>] (sysfs_write_file+0x168/0x198) from [<c01382c4>] (vfs_write+0x9c/0x170)
[   36.271112] [<c01382c4>] (vfs_write+0x9c/0x170) from [<c0138440>] (sys_write+0x38/0x70)
[   36.271173] [<c0138440>] (sys_write+0x38/0x70) from [<c000f000>] (ret_fast_syscall+0x0/0x30)
[   36.271265] Code: e7925001 e3550000 0a000033 e5942014 (e795a002)
[   36.271661] ---[ end trace ef0d8b9c8acc7bbb ]---
msm: kgsl: Import conservative governor from jb422 branch
msm: kgsl: Add touchboost to conservative governor

Greatly helps against infamous micro-stutters.
msm: kgsl: Report GPU frequency correctly in sysfs
kgsl_pwrscale_conservative: fix touch-boost
msm: acpuclock-8064: Add 189MHz step
msm: overclock cpu to 1.944GHz
Revert "lm3530: Add a toggle for the CABC PWM"

This reverts commit cdfd0080af4768b62f31c3a5b45966d6a6cc1988.
video: lm3530_bl: Introduce new tunables to control LED driver

- min_br: sets the mininum brightness level (2-114)
- max_br: sets the maximum brightness level (2-114)
- br_mode: sets the linear (default 1) or exponential (0) brightness
mapping mode.

Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
video: lm3530_bl: Fix a couple of checkpatch warnings

Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
video: lm3530_bl: Fix backlight issue when suspend

Revert the min brightness check that prevents the driver
to turn off backlight when suspend.

Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
softirq: reduce latencies

In various network workloads, __do_softirq() latencies can be up
to 20 ms if HZ=1000, and 200 ms if HZ=100.

This is because we iterate 10 times in the softirq dispatcher,
and some actions can consume a lot of cycles.

This patch changes the fallback to ksoftirqd condition to :

- A time limit of 2 ms.
- need_resched() being set on current task

When one of this condition is met, we wakeup ksoftirqd for further
softirq processing if we still have pending softirqs.

Using need_resched() as the only condition can trigger RCU stalls,
as we can keep BH disabled for too long.

I ran several benchmarks and got no significant difference in
throughput, but a very significant reduction of latencies (one order
of magnitude) :

In following bench, 200 antagonist "netperf -t TCP_RR" are started in
background, using all available cpus.

Then we start one "netperf -t TCP_RR", bound to the cpu handling the NIC
IRQ (hard+soft)

Before patch :

# netperf -H 7.7.7.84 -t TCP_RR -T2,2 -- -k
RT_LATENCY,MIN_LATENCY,MAX_LATENCY,P50_LATENCY,P90_LATENCY,P99_LATENCY,MEAN_LATENCY,STDDEV_LATENCY
MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET
to 7.7.7.84 () port 0 AF_INET : first burst 0 : cpu bind
RT_LATENCY=550110.424
MIN_LATENCY=146858
MAX_LATENCY=997109
P50_LATENCY=305000
P90_LATENCY=550000
P99_LATENCY=710000
MEAN_LATENCY=376989.12
STDDEV_LATENCY=184046.92

After patch :

# netperf -H 7.7.7.84 -t TCP_RR -T2,2 -- -k
RT_LATENCY,MIN_LATENCY,MAX_LATENCY,P50_LATENCY,P90_LATENCY,P99_LATENCY,MEAN_LATENCY,STDDEV_LATENCY
MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET
to 7.7.7.84 () port 0 AF_INET : first burst 0 : cpu bind
RT_LATENCY=40545.492
MIN_LATENCY=9834
MAX_LATENCY=78366
P50_LATENCY=33583
P90_LATENCY=59000
P99_LATENCY=69000
MEAN_LATENCY=38364.67
STDDEV_LATENCY=12865.26

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: David Miller <davem@davemloft.net>
Cc: Tom Herbert <therbert@google.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
v1.5