[PATCH RFC 07/11] SUNRPC: let procfs copy in writes

@@ -1408,8 +1408,8 @@ svcauth_gss_proc_init(struct svc_rqst *rqstp, struct rpc_gss_wire_cred *gc)
 
 #ifdef CONFIG_PROC_FS
 
-static ssize_t write_gssp(struct file *file, const char __user *buf,
-			 size_t count, loff_t *ppos)
+static ssize_t write_gssp(struct file *file, char *buf, size_t count,
+			  loff_t *ppos)
 {
 	struct net *net = pde_data(file_inode(file));
 	char tbuf[20];

@@ -1418,9 +1418,7 @@ static ssize_t write_gssp(struct file *file, const char __user *buf,
 
 	if (*ppos || count > sizeof(tbuf)-1)
 		return -EINVAL;
-	if (copy_from_user(tbuf, buf, count))
-		return -EFAULT;
-
+	memcpy(tbuf, buf, count);
 	tbuf[count] = 0;
 	res = kstrtoul(tbuf, 0, &i);
 	if (res)

@@ -1468,7 +1466,7 @@ static ssize_t read_gssp(struct file *file, char __user *buf,
 
 static const struct proc_ops use_gss_proxy_proc_ops = {
 	.proc_open	= nonseekable_open,
-	.proc_write	= write_gssp,
+	.proc_write_buf	= write_gssp,
 	.proc_read	= read_gssp,
 };
 

@@ -924,6 +924,9 @@ static ssize_t cache_do_downcall(char *kaddr, const char __user *buf,
 	return ret;
 }
 
+/* 32k is max userland buffer, lets check anyway */
+#define CACHE_DOWNCALL_MAX	(32768 - 1)
+
 static ssize_t cache_downcall(struct address_space *mapping,
 			      const char __user *buf,
 			      size_t count, struct cache_detail *cd)

@@ -931,7 +934,7 @@ static ssize_t cache_downcall(struct address_space *mapping,
 	char *write_buf;
 	ssize_t ret = -ENOMEM;
 
-	if (count >= 32768) { /* 32k is max userland buffer, lets check anyway */
+	if (count > CACHE_DOWNCALL_MAX) {
 		ret = -EINVAL;
 		goto out;
 	}

@@ -1508,19 +1511,15 @@ static ssize_t read_flush(struct file *file, char __user *buf,
 	return simple_read_from_buffer(buf, count, ppos, tbuf, len);
 }
 
-static ssize_t write_flush(struct file *file, const char __user *buf,
-			   size_t count, loff_t *ppos,
-			   struct cache_detail *cd)
+/* longest number the flush files take */
+#define CACHE_FLUSH_MAX		19
+
+static ssize_t do_write_flush(char *tbuf, size_t count, loff_t *ppos,
+			      struct cache_detail *cd)
 {
-	char tbuf[20];
 	char *ep;
 	time64_t now;
 
-	if (*ppos || count > sizeof(tbuf)-1)
-		return -EINVAL;
-	if (copy_from_user(tbuf, buf, count))
-		return -EFAULT;
-	tbuf[count] = 0;
 	simple_strtoul(tbuf, &ep, 0);
 	if (*ep && *ep != '\n')
 		return -EINVAL;

@@ -1551,6 +1550,20 @@ static ssize_t write_flush(struct file *file, const char __user *buf,
 	return count;
 }
 
+static ssize_t write_flush(struct file *file, const char __user *buf,
+			   size_t count, loff_t *ppos,
+			   struct cache_detail *cd)
+{
+	char tbuf[CACHE_FLUSH_MAX + 1];
+
+	if (*ppos || count > CACHE_FLUSH_MAX)
+		return -EINVAL;
+	if (copy_from_user(tbuf, buf, count))
+		return -EFAULT;
+	tbuf[count] = 0;
+	return do_write_flush(tbuf, count, ppos, cd);
+}
+
 static ssize_t cache_read_procfs(struct file *filp, char __user *buf,
 				 size_t count, loff_t *ppos)
 {

@@ -1559,12 +1572,21 @@ static ssize_t cache_read_procfs(struct file *filp, char __user *buf,
 	return cache_read(filp, buf, count, ppos, cd);
 }
 
-static ssize_t cache_write_procfs(struct file *filp, const char __user *buf,
-				  size_t count, loff_t *ppos)
+/* procfs copied in what was written */
+static ssize_t cache_write_procfs(struct file *filp, char *buf, size_t count,
+				  loff_t *ppos)
 {
 	struct cache_detail *cd = pde_data(file_inode(filp));
+	struct inode *inode = file_inode(filp);
+	ssize_t ret;
 
-	return cache_write(filp, buf, count, ppos, cd);
+	if (!cd->cache_parse || !count)
+		return -EINVAL;
+
+	inode_lock(inode);
+	ret = cd->cache_parse(cd, buf, count);
+	inode_unlock(inode);
+	return ret ? ret : count;
 }
 
 static __poll_t cache_poll_procfs(struct file *filp, poll_table *wait)

@@ -1599,7 +1621,8 @@ static int cache_release_procfs(struct inode *inode, struct file *filp)
 
 static const struct proc_ops cache_channel_proc_ops = {
 	.proc_read	= cache_read_procfs,
-	.proc_write	= cache_write_procfs,
+	.proc_write_buf	= cache_write_procfs,
+	.proc_write_size = CACHE_DOWNCALL_MAX,
 	.proc_poll	= cache_poll_procfs,
 	.proc_ioctl	= cache_ioctl_procfs, /* for FIONREAD */
 	.proc_open	= cache_open_procfs,

@@ -1653,19 +1676,21 @@ static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
 	return read_flush(filp, buf, count, ppos, cd);
 }
 
-static ssize_t write_flush_procfs(struct file *filp,
-				  const char __user *buf,
-				  size_t count, loff_t *ppos)
+static ssize_t write_flush_procfs(struct file *filp, char *buf, size_t count,
+				  loff_t *ppos)
 {
 	struct cache_detail *cd = pde_data(file_inode(filp));
 
-	return write_flush(filp, buf, count, ppos, cd);
+	if (*ppos)
+		return -EINVAL;
+	return do_write_flush(buf, count, ppos, cd);
 }
 
 static const struct proc_ops cache_flush_proc_ops = {
 	.proc_open	= open_flush_procfs,
 	.proc_read	= read_flush_procfs,
-	.proc_write	= write_flush_procfs,
+	.proc_write_buf	= write_flush_procfs,
+	.proc_write_size = CACHE_FLUSH_MAX,
 	.proc_release	= release_flush_procfs,
 };