[PATCH RFC 08/11] SUNRPC: let procfs copy out reads

@@ -1442,32 +1442,22 @@ static ssize_t write_gssp(struct file *file, char *buf, size_t count,
 	return count;
 }
 
-static ssize_t read_gssp(struct file *file, char __user *buf,
+static ssize_t read_gssp(struct file *file, char *buf,
 			 size_t count, loff_t *ppos)
 {
 	struct net *net = pde_data(file_inode(file));
 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
-	unsigned long p = *ppos;
 	char tbuf[10];
 	size_t len;
 
-	snprintf(tbuf, sizeof(tbuf), "%d\n", sn->use_gss_proxy);
-	len = strlen(tbuf);
-	if (p >= len)
-		return 0;
-	len -= p;
-	if (len > count)
-		len = count;
-	if (copy_to_user(buf, (void *)(tbuf+p), len))
-		return -EFAULT;
-	*ppos += len;
-	return len;
+	len = snprintf(tbuf, sizeof(tbuf), "%d\n", sn->use_gss_proxy);
+	return memory_read_from_buffer(buf, count, ppos, tbuf, len);
 }
 
 static const struct proc_ops use_gss_proxy_proc_ops = {
 	.proc_open	= nonseekable_open,
 	.proc_write_buf	= write_gssp,
-	.proc_read	= read_gssp,
+	.proc_read_buf	= read_gssp,
 };
 
 static int create_use_gss_proxy_proc_entry(struct net *net)

@@ -1494,7 +1484,7 @@ static void destroy_use_gss_proxy_proc_entry(struct net *net)
 	}
 }
 
-static ssize_t read_gss_krb5_enctypes(struct file *file, char __user *buf,
+static ssize_t read_gss_krb5_enctypes(struct file *file, char *buf,
 				      size_t count, loff_t *ppos)
 {
 	struct rpcsec_gss_oid oid = {

@@ -1512,7 +1502,7 @@ static ssize_t read_gss_krb5_enctypes(struct file *file, char __user *buf,
 		return 0;
 	}
 
-	ret = simple_read_from_buffer(buf, count, ppos,
+	ret = memory_read_from_buffer(buf, count, ppos,
 				      mech->gm_upcall_enctypes,
 				      strlen(mech->gm_upcall_enctypes));
 	gss_mech_put(mech);

@@ -1521,7 +1511,7 @@ static ssize_t read_gss_krb5_enctypes(struct file *file, char __user *buf,
 
 static const struct proc_ops gss_krb5_enctypes_proc_ops = {
 	.proc_open	= nonseekable_open,
-	.proc_read	= read_gss_krb5_enctypes,
+	.proc_read_buf	= read_gss_krb5_enctypes,
 };
 
 static int create_krb5_enctypes_proc_entry(struct net *net)

@@ -28,6 +28,7 @@
 #include <linux/workqueue.h>
 #include <linux/mutex.h>
 #include <linux/pagemap.h>
+#include <linux/uio.h>
 #include <asm/ioctls.h>
 #include <linux/sunrpc/types.h>
 #include <linux/sunrpc/cache.h>

@@ -837,9 +838,10 @@ cache_next_request(struct cache_detail *cd, u64 seqno)
 	return NULL;
 }
 
-static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
-			  loff_t *ppos, struct cache_detail *cd)
+static ssize_t cache_read(struct file *filp, struct iov_iter *to,
+			  struct cache_detail *cd)
 {
+	size_t count = iov_iter_count(to);
 	struct cache_reader *rp = filp->private_data;
 	struct cache_request *rq;
 	struct inode *inode = file_inode(filp);

@@ -878,7 +880,7 @@ static ssize_t cache_read(struct file *filp, char __user *buf, size_t count,
 		if (rp->offset + count > rq->len)
 			count = rq->len - rp->offset;
 		err = -EFAULT;
-		if (copy_to_user(buf, rq->buf + rp->offset, count))
+		if (copy_to_iter(rq->buf + rp->offset, count, to) != count)
 			goto out;
 		rp->offset += count;
 		if (rp->offset >= rq->len) {

@@ -1499,16 +1501,11 @@ static int release_flush(struct inode *inode, struct file *file,
 	return 0;
 }
 
-static ssize_t read_flush(struct file *file, char __user *buf,
-			  size_t count, loff_t *ppos,
-			  struct cache_detail *cd)
+/* what reading the flush files returns */
+static size_t flush_time_text(struct cache_detail *cd, char *tbuf, size_t size)
 {
-	char tbuf[22];
-	size_t len;
-
-	len = snprintf(tbuf, sizeof(tbuf), "%llu\n",
+	return snprintf(tbuf, size, "%llu\n",
 			convert_to_wallclock(cd->flush_time));
-	return simple_read_from_buffer(buf, count, ppos, tbuf, len);
 }
 
 /* longest number the flush files take */

@@ -1564,12 +1561,15 @@ static ssize_t write_flush(struct file *file, const char __user *buf,
 	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)
+static ssize_t cache_read_procfs(struct file *filp, char *buf, size_t count,
+				 loff_t *ppos)
 {
 	struct cache_detail *cd = pde_data(file_inode(filp));
+	struct kvec kvec = { .iov_base = buf, .iov_len = count };
+	struct iov_iter to;
 
-	return cache_read(filp, buf, count, ppos, cd);
+	iov_iter_kvec(&to, ITER_DEST, &kvec, 1, count);
+	return cache_read(filp, &to, cd);
 }
 
 /* procfs copied in what was written */

@@ -1620,7 +1620,7 @@ 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_read_buf	= cache_read_procfs,
 	.proc_write_buf	= cache_write_procfs,
 	.proc_write_size = CACHE_DOWNCALL_MAX,
 	.proc_poll	= cache_poll_procfs,

@@ -1668,12 +1668,15 @@ static int release_flush_procfs(struct inode *inode, struct file *filp)
 	return release_flush(inode, filp, cd);
 }
 
-static ssize_t read_flush_procfs(struct file *filp, char __user *buf,
-			    size_t count, loff_t *ppos)
+static ssize_t read_flush_procfs(struct file *filp, char *buf, size_t count,
+				 loff_t *ppos)
 {
 	struct cache_detail *cd = pde_data(file_inode(filp));
+	char tbuf[22];
+	size_t len;
 
-	return read_flush(filp, buf, count, ppos, cd);
+	len = flush_time_text(cd, tbuf, sizeof(tbuf));
+	return memory_read_from_buffer(buf, count, ppos, tbuf, len);
 }
 
 static ssize_t write_flush_procfs(struct file *filp, char *buf, size_t count,

@@ -1688,7 +1691,7 @@ static ssize_t write_flush_procfs(struct file *filp, char *buf, size_t count,
 
 static const struct proc_ops cache_flush_proc_ops = {
 	.proc_open	= open_flush_procfs,
-	.proc_read	= read_flush_procfs,
+	.proc_read_buf	= read_flush_procfs,
 	.proc_write_buf	= write_flush_procfs,
 	.proc_write_size = CACHE_FLUSH_MAX,
 	.proc_release	= release_flush_procfs,

@@ -1795,8 +1798,10 @@ static ssize_t cache_read_pipefs(struct file *filp, char __user *buf,
 				 size_t count, loff_t *ppos)
 {
 	struct cache_detail *cd = RPC_I(file_inode(filp))->private;
+	struct iov_iter to;
 
-	return cache_read(filp, buf, count, ppos, cd);
+	iov_iter_ubuf(&to, ITER_DEST, buf, count);
+	return cache_read(filp, &to, cd);
 }
 
 static ssize_t cache_write_pipefs(struct file *filp, const char __user *buf,

@@ -1886,8 +1891,11 @@ static ssize_t read_flush_pipefs(struct file *filp, char __user *buf,
 			    size_t count, loff_t *ppos)
 {
 	struct cache_detail *cd = RPC_I(file_inode(filp))->private;
+	char tbuf[22];
+	size_t len;
 
-	return read_flush(filp, buf, count, ppos, cd);
+	len = flush_time_text(cd, tbuf, sizeof(tbuf));
+	return simple_read_from_buffer(buf, count, ppos, tbuf, len);
 }
 
 static ssize_t write_flush_pipefs(struct file *filp,