[PATCH RFC 17/27] sched/psi: let procfs copy in trigger writes

@@ -1535,8 +1535,8 @@ static int psi_cpu_show(struct seq_file *m, void *v)
 	return psi_show(m, &psi_system, PSI_CPU);
 }
 
-static ssize_t psi_write(struct file *file, const char __user *user_buf,
-			 size_t nbytes, enum psi_res res)
+static ssize_t psi_write(struct file *file, const char *kbuf, size_t nbytes,
+			 enum psi_res res)
 {
 	char buf[32];
 	size_t buf_size;

@@ -1552,9 +1552,7 @@ static ssize_t psi_write(struct file *file, const char __user *user_buf,
 		return -EINVAL;
 
 	buf_size = min(nbytes, sizeof(buf));
-	if (copy_from_user(buf, user_buf, buf_size))
-		return -EFAULT;
-
+	memcpy(buf, kbuf, buf_size);
 	buf[buf_size - 1] = '\0';
 
 	seq = file->private_data;

@@ -1590,22 +1588,22 @@ static ssize_t psi_write(struct file *file, const char __user *user_buf,
 	return nbytes;
 }
 
-static ssize_t psi_io_write(struct file *file, const char __user *user_buf,
-			    size_t nbytes, loff_t *ppos)
+static ssize_t psi_io_write(struct file *file, char *buf, size_t nbytes,
+			    loff_t *ppos)
 {
-	return psi_write(file, user_buf, nbytes, PSI_IO);
+	return psi_write(file, buf, nbytes, PSI_IO);
 }
 
-static ssize_t psi_memory_write(struct file *file, const char __user *user_buf,
-				size_t nbytes, loff_t *ppos)
+static ssize_t psi_memory_write(struct file *file, char *buf, size_t nbytes,
+				loff_t *ppos)
 {
-	return psi_write(file, user_buf, nbytes, PSI_MEM);
+	return psi_write(file, buf, nbytes, PSI_MEM);
 }
 
-static ssize_t psi_cpu_write(struct file *file, const char __user *user_buf,
-			     size_t nbytes, loff_t *ppos)
+static ssize_t psi_cpu_write(struct file *file, char *buf, size_t nbytes,
+			     loff_t *ppos)
 {
-	return psi_write(file, user_buf, nbytes, PSI_CPU);
+	return psi_write(file, buf, nbytes, PSI_CPU);
 }
 
 static __poll_t psi_fop_poll(struct file *file, poll_table *wait)

@@ -1625,21 +1623,21 @@ static int psi_fop_release(struct inode *inode, struct file *file)
 
 static const struct proc_ops psi_io_proc_ops = {
 	.proc_show	= psi_io_show,
-	.proc_write	= psi_io_write,
+	.proc_write_buf	= psi_io_write,
 	.proc_poll	= psi_fop_poll,
 	.proc_release	= psi_fop_release,
 };
 
 static const struct proc_ops psi_memory_proc_ops = {
 	.proc_show	= psi_memory_show,
-	.proc_write	= psi_memory_write,
+	.proc_write_buf	= psi_memory_write,
 	.proc_poll	= psi_fop_poll,
 	.proc_release	= psi_fop_release,
 };
 
 static const struct proc_ops psi_cpu_proc_ops = {
 	.proc_show	= psi_cpu_show,
-	.proc_write	= psi_cpu_write,
+	.proc_write_buf	= psi_cpu_write,
 	.proc_poll	= psi_fop_poll,
 	.proc_release	= psi_fop_release,
 };

@@ -1650,15 +1648,15 @@ static int psi_irq_show(struct seq_file *m, void *v)
 	return psi_show(m, &psi_system, PSI_IRQ);
 }
 
-static ssize_t psi_irq_write(struct file *file, const char __user *user_buf,
-			     size_t nbytes, loff_t *ppos)
+static ssize_t psi_irq_write(struct file *file, char *buf, size_t nbytes,
+			     loff_t *ppos)
 {
-	return psi_write(file, user_buf, nbytes, PSI_IRQ);
+	return psi_write(file, buf, nbytes, PSI_IRQ);
 }
 
 static const struct proc_ops psi_irq_proc_ops = {
 	.proc_show	= psi_irq_show,
-	.proc_write	= psi_irq_write,
+	.proc_write_buf	= psi_irq_write,
 	.proc_poll	= psi_fop_poll,
 	.proc_release	= psi_fop_release,
 };