Merge lineage-20 of git@github.com:LineageOS/android_kernel_qcom_msm8998.git into lineage-20

7d11b1a7a11c Revert "sched: cpufreq: Use sched_clock instead of rq_clock when updating schedutil"
daaa5da96a74 sched: Take irq_sparse lock during the isolation
217ab2d0ef91 rcu: Speed up calling of RCU tasks callbacks
997b726bc092 kernel: power: Workaround for sensor ipc message causing high power consume
b933e4d37bc0 sched/fair: Fix low cpu usage with high throttling by removing expiration of cpu-local slices
82d3f23d6dc5 sched/fair: Fix bandwidth timer clock drift condition
629bfed360f9 kernel: power: qos: remove check for core isolation while cluster LPMs
891a63210e1d sched/fair: Fix issue where frequency update not skipped
b775cb29f663 ANDROID: Move schedtune en/dequeue before schedutil update triggers
ebdb82f7b34a sched/fair: Skip frequency updates if CPU about to idle
ff383d94478a FROMLIST: sched: Make iowait_boost optional in schedutil
9539942cb065 FROMLIST: cpufreq: Make iowait boost a policy option
b65c91c9aa14 ARM: dts: msm: add HW CPU's busy-cost-data for additional freqs
72f13941085b ARM: dts: msm: fix CPU's idle-cost-data
ab88411382f7 ARM: dts: msm: fix EM to be monotonically increasing
83dcbae14782 ARM: dts: msm: Fix EAS idle-cost-data property length
33d3b17bfdfb ARM: dts: msm: Add msm8998 energy model
c0fa7577022c sched/walt: Re-add code to allow WALT to function
d5cd35f38616 FROMGIT: binder: use EINTR for interrupted wait for work
db74739c86de sched: Don't fail isolation request for an already isolated CPU
aee7a16e347b sched: WALT: increase WALT minimum window size to 20ms
4dbe44554792 sched: cpufreq: Use per_cpu_ptr instead of this_cpu_ptr when reporting load
ef3fb04c7df4 sched: cpufreq: Use sched_clock instead of rq_clock when updating schedutil
c7128748614a sched/cpupri: Exclude isolated CPUs from the lowest_mask
6adb092856e8 sched: cpufreq: Limit governor updates to WALT changes alone
0fa652ee00f5 sched: walt: Correct WALT window size initialization
41cbb7bc59fb sched: walt: fix window misalignment when HZ=300
43cbf9d6153d sched/tune: Increase the cgroup limit to 6
c71b8fffe6b3 drivers: cpuidle: lpm-levels: Fix KW issues with idle state idx < 0
938e42ca699f drivers: cpuidle: lpm-levels: Correctly check for list empty
8d8a48aecde5 sched/fair: Fix load_balance() affinity redo path
eccc8acbe705 sched/fair: Avoid unnecessary active load balance
0ffdb886996b BACKPORT: sched/core: Fix rules for running on online && !active CPUs
c9999f04236e sched/core: Allow kthreads to fall back to online && !active cpus
b9b6bc6ea3c0 sched: Allow migrating kthreads into online but inactive CPUs
a9314f9d8ad4 sched/fair: Allow load bigger task load balance when nr_running is 2
c0b317c27d44 pinctrl: qcom: Clear status bit on irq_unmask
45df1516d04a UPSTREAM: mm: fix misplaced unlock_page in do_wp_page()
899def5edcd4 UPSTREAM: mm/ksm: Remove reuse_ksm_page()
46c6fbdd185a BACKPORT: mm: do_wp_page() simplification
90dccbae4c04 UPSTREAM: mm: reuse only-pte-mapped KSM page in do_wp_page()
ebf270d24640 sched/fair: vruntime should normalize when switching from  fair
cbe0b37059c9 mm: introduce arg_lock to protect arg_start|end and  env_start|end in mm_struct
12d40f1995b4 msm: mdss: Fix indentation
620df03a7229 msm: mdss: Treat polling_en as the bool that it is
12af218146a6 msm: mdss: add idle state node
13e661759656 cpuset: Restore tasks affinity while moving across cpusets
602bf4096dab genirq: Honour IRQ's affinity hint during migration
9209b5556f6a power: qos: Use effective affinity mask
f31078b5825f genirq: Introduce effective affinity mask
58c453484f7e sched/cputime: Mitigate performance regression in times()/clock_gettime()
400383059868 kernel: time: Add delay after cpu_relax() in tight loops
1daa7ea39076 pinctrl: qcom: Update irq handle for GPIO pins
07f7c9961c7c power: smb-lib: Fix mutex acquisition deadlock on PD hard reset
094b738f46c8 power: qpnp-smb2: Implement battery charging_enabled node
d6038d6da57f ASoC: msm-pcm-q6-v2: Add dsp buf check
0d7a6c301af8 qcacld-3.0: Fix OOB in wma_scan_roam.c

Change-Id: Ia2e189e37daad6e99bdb359d1204d9133a7916f4

1 files changed, 17 insertions, 25 deletions

diff --git a/mm/memory.c b/mm/memory.c
index 09a57fe6ae01..0c69908d3eed 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2399,39 +2399,31 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	 * Take out anonymous pages first, anonymous shared vmas are
 	 * not dirty accountable.
 	 */
-	if (PageAnon(old_page) && !PageKsm(old_page)) {
-		if (!trylock_page(old_page)) {
-			page_cache_get(old_page);
-			pte_unmap_unlock(page_table, ptl);
-			lock_page(old_page);
-			page_table = pte_offset_map_lock(mm, pmd, address,
-							 &ptl);
-			if (!pte_same(*page_table, orig_pte)) {
-				unlock_page(old_page);
-				pte_unmap_unlock(page_table, ptl);
-				page_cache_release(old_page);
-				return 0;
-			}
-			page_cache_release(old_page);
-		}
-		if (reuse_swap_page(old_page)) {
-			/*
-			 * The page is all ours.  Move it to our anon_vma so
-			 * the rmap code will not search our parent or siblings.
-			 * Protected against the rmap code by the page lock.
-			 */
-			page_move_anon_rmap(old_page, vma, address);
+	if (PageAnon(old_page)) {
+		/* PageKsm() doesn't necessarily raise the page refcount */
+		if (PageKsm(old_page) || page_count(old_page) != 1)
+			goto copy;
+		if (!trylock_page(old_page))
+			goto copy;
+		if (PageKsm(old_page) || page_mapcount(old_page) != 1 || page_count(old_page) != 1) {
 			unlock_page(old_page);
-			return wp_page_reuse(mm, vma, address, page_table, ptl,
-					     orig_pte, old_page, 0, 0);
+			goto copy;
 		}
+		/*
+		 * Ok, we've got the only map reference, and the only
+		 * page count reference, and the page is locked,
+		 * it's dark out, and we're wearing sunglasses. Hit it.
+		 */
 		unlock_page(old_page);
+		wp_page_reuse(mm, vma, address, page_table, ptl,
+			      orig_pte, old_page, 0, 0);
+		return VM_FAULT_WRITE;
 	} else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
 					(VM_WRITE|VM_SHARED))) {
 		return wp_page_shared(mm, vma, address, page_table, pmd,
 				      ptl, orig_pte, old_page);
 	}
-
+copy:
 	/*
 	 * Ok, we need to copy. Oh, well..
 	 */