Merge commit '6355b448f58608fdcc30c0421f417a27600b6933' into HEAD

Change-Id: Ib9ac29e1040396d1d6996f0d4f4e865af02af901
Signed-off-by: Shreyas Narayan <shrena@codeaurora.org>

5 files changed, 33 insertions, 8 deletions

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 210ccc4ea44b..8607c937145f 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -453,7 +453,7 @@ static inline struct cgroup_subsys_state *task_css(struct task_struct *task,
  *
  * Find the css for the (@task, @subsys_id) combination, increment a
  * reference on and return it.  This function is guaranteed to return a
- * valid css.
+ * valid css.  The returned css may already have been offlined.
  */
 static inline struct cgroup_subsys_state *
 task_get_css(struct task_struct *task, int subsys_id)
@@ -463,7 +463,13 @@ task_get_css(struct task_struct *task, int subsys_id)
 	rcu_read_lock();
 	while (true) {
 		css = task_css(task, subsys_id);
-		if (likely(css_tryget_online(css)))
+		/*
+		 * Can't use css_tryget_online() here.  A task which has
+		 * PF_EXITING set may stay associated with an offline css.
+		 * If such task calls this function, css_tryget_online()
+		 * will keep failing.
+		 */
+		if (likely(css_tryget(css)))
 			break;
 		cpu_relax();
 	}
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 47c7bb494c74..ecdabf3597ae 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1115,6 +1115,27 @@ void zap_page_range(struct vm_area_struct *vma, unsigned long address,
 void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
 		unsigned long start, unsigned long end);
 
+/*
+ * This has to be called after a get_task_mm()/mmget_not_zero()
+ * followed by taking the mmap_sem for writing before modifying the
+ * vmas or anything the coredump pretends not to change from under it.
+ *
+ * NOTE: find_extend_vma() called from GUP context is the only place
+ * that can modify the "mm" (notably the vm_start/end) under mmap_sem
+ * for reading and outside the context of the process, so it is also
+ * the only case that holds the mmap_sem for reading that must call
+ * this function. Generally if the mmap_sem is hold for reading
+ * there's no need of this check after get_task_mm()/mmget_not_zero().
+ *
+ * This function can be obsoleted and the check can be removed, after
+ * the coredump code will hold the mmap_sem for writing before
+ * invoking the ->core_dump methods.
+ */
+static inline bool mmget_still_valid(struct mm_struct *mm)
+{
+	return likely(!mm->core_state);
+}
+
 /**
  * mm_walk - callbacks for walk_page_range
  * @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index aa8736d5b2f3..cfc3ed46cad2 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -331,7 +331,6 @@ static inline void pwm_remove_table(struct pwm_lookup *table, size_t num)
 #ifdef CONFIG_PWM_SYSFS
 void pwmchip_sysfs_export(struct pwm_chip *chip);
 void pwmchip_sysfs_unexport(struct pwm_chip *chip);
-void pwmchip_sysfs_unexport_children(struct pwm_chip *chip);
 #else
 static inline void pwmchip_sysfs_export(struct pwm_chip *chip)
 {
@@ -340,10 +339,6 @@ static inline void pwmchip_sysfs_export(struct pwm_chip *chip)
 static inline void pwmchip_sysfs_unexport(struct pwm_chip *chip)
 {
 }
-
-static inline void pwmchip_sysfs_unexport_children(struct pwm_chip *chip)
-{
-}
 #endif /* CONFIG_PWM_SYSFS */
 
 #endif /* __LINUX_PWM_H */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index ccd0f37dcff7..2378cbf2612d 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -378,7 +378,7 @@ extern int lockdep_tasklist_lock_is_held(void);
 extern void sched_init(void);
 extern void sched_init_smp(void);
 extern asmlinkage void schedule_tail(struct task_struct *prev);
-extern void init_idle(struct task_struct *idle, int cpu, bool hotplug);
+extern void init_idle(struct task_struct *idle, int cpu);
 extern void init_idle_bootup_task(struct task_struct *idle);
 
 extern cpumask_var_t cpu_isolated_map;
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 747404dbe506..085da1707cea 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -419,4 +419,7 @@ static inline void tcp_saved_syn_free(struct tcp_sock *tp)
 	tp->saved_syn = NULL;
 }
 
+int tcp_skb_shift(struct sk_buff *to, struct sk_buff *from, int pcount,
+		  int shiftlen);
+
 #endif	/* _LINUX_TCP_H */