Revert "sched/core: fix userspace affining threads incorrectly"

This reverts commit d43b69c4ad.

Bug:133481659
Test: build
Change-Id: I615023c611c4de1eb334e4374af7306991f4216b
Signed-off-by: Wei Wang <wvw@google.com>

include/linux/sched.h

@@ -1968,7 +1968,6 @@ static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
 # define vcpu_is_preempted(cpu)	false
 #endif
 
-extern long msm_sched_setaffinity(pid_t pid, struct cpumask *new_mask);
 extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
 extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
 

include/linux/sched/sysctl.h

@@ -134,9 +134,4 @@ extern int sched_little_cluster_coloc_fmin_khz_handler(struct ctl_table *table,
 					size_t *lenp, loff_t *ppos);
 #endif
 
-#define LIB_PATH_LENGTH 512
-extern char sched_lib_name[LIB_PATH_LENGTH];
-extern unsigned int sched_lib_mask_check;
-extern unsigned int sched_lib_mask_force;
-
 #endif /* _LINUX_SCHED_SYSCTL_H */

kernel/compat.c

@@ -334,7 +334,7 @@ COMPAT_SYSCALL_DEFINE3(sched_setaffinity, compat_pid_t, pid,
 	if (retval)
 		goto out;
 
-	retval = msm_sched_setaffinity(pid, new_mask);
+	retval = sched_setaffinity(pid, new_mask);
 out:
 	free_cpumask_var(new_mask);
 	return retval;

kernel/sched/core.c

@@ -4931,71 +4931,6 @@ out_put_task:
 	return retval;
 }
 
-char sched_lib_name[LIB_PATH_LENGTH];
-unsigned int sched_lib_mask_check;
-unsigned int sched_lib_mask_force;
-static inline bool is_sched_lib_based_app(pid_t pid)
-{
-	const char *name = NULL;
-	struct vm_area_struct *vma;
-	char path_buf[LIB_PATH_LENGTH];
-	bool found = false;
-	struct task_struct *p;
-
-	if (strnlen(sched_lib_name, LIB_PATH_LENGTH) == 0)
-		return false;
-
-	rcu_read_lock();
-
-	p = find_process_by_pid(pid);
-	if (!p) {
-		rcu_read_unlock();
-		return false;
-	}
-
-	/* Prevent p going away */
-	get_task_struct(p);
-	rcu_read_unlock();
-
-	if (!p->mm)
-		goto put_task_struct;
-
-	down_read(&p->mm->mmap_sem);
-	for (vma = p->mm->mmap; vma ; vma = vma->vm_next) {
-		if (vma->vm_file && vma->vm_flags & VM_EXEC) {
-			name = d_path(&vma->vm_file->f_path,
-					path_buf, LIB_PATH_LENGTH);
-			if (IS_ERR(name))
-				goto release_sem;
-
-			if (strnstr(name, sched_lib_name,
-					strnlen(name, LIB_PATH_LENGTH))) {
-				found = true;
-				break;
-			}
-		}
-	}
-
-release_sem:
-	up_read(&p->mm->mmap_sem);
-put_task_struct:
-	put_task_struct(p);
-	return found;
-}
-
-long msm_sched_setaffinity(pid_t pid, struct cpumask *new_mask)
-{
-	if (sched_lib_mask_check != 0 && sched_lib_mask_force != 0 &&
-		(cpumask_bits(new_mask)[0] == sched_lib_mask_check) &&
-		is_sched_lib_based_app(pid)) {
-
-		cpumask_t forced_mask = { {sched_lib_mask_force} };
-
-		cpumask_copy(new_mask, &forced_mask);
-	}
-	return sched_setaffinity(pid, new_mask);
-}
-
 static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
 			     struct cpumask *new_mask)
 {
@@ -5026,7 +4961,7 @@ SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
 
 	retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
 	if (retval == 0)
-		retval = msm_sched_setaffinity(pid, new_mask);
+		retval = sched_setaffinity(pid, new_mask);
 	free_cpumask_var(new_mask);
 	return retval;
 }

kernel/sysctl.c

@@ -147,7 +147,6 @@ static int ten_thousand = 10000;
 #ifdef CONFIG_PERF_EVENTS
 static int six_hundred_forty_kb = 640 * 1024;
 #endif
-static int two_hundred_fifty_five = 255;
 
 /* this is needed for the proc_doulongvec_minmax of vm_dirty_bytes */
 static unsigned long dirty_bytes_min = 2 * PAGE_SIZE;
@@ -637,31 +636,6 @@ static struct ctl_table kern_table[] = {
 		.extra1		= &one,
 	},
 #endif
-	{
-		.procname	= "sched_lib_name",
-		.data		= sched_lib_name,
-		.maxlen		= LIB_PATH_LENGTH,
-		.mode		= 0644,
-		.proc_handler	= proc_dostring,
-	},
-	{
-		.procname	= "sched_lib_mask_check",
-		.data		= &sched_lib_mask_check,
-		.maxlen		= sizeof(unsigned int),
-		.mode		= 0644,
-		.proc_handler	= proc_douintvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &two_hundred_fifty_five,
-	},
-	{
-		.procname	= "sched_lib_mask_force",
-		.data		= &sched_lib_mask_force,
-		.maxlen		= sizeof(unsigned int),
-		.mode		= 0644,
-		.proc_handler	= proc_douintvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &two_hundred_fifty_five,
-	},
 #ifdef CONFIG_PROVE_LOCKING
 	{
 		.procname	= "prove_locking",