X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=fs%2Fseq_file.c;h=555b9ac04c25be9ac5354bea2810ef79290ab92e;hb=a43a8c39bbb493c9e93f6764b350de2e33e18e92;hp=650c43ba86c4791e6dcb74af55b5ab77a3258a1c;hpb=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2;p=linux-2.6

diff --git a/fs/seq_file.c b/fs/seq_file.c
index 650c43ba86..555b9ac04c 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -28,13 +28,17 @@
  */
 int seq_open(struct file *file, struct seq_operations *op)
 {
-	struct seq_file *p = kmalloc(sizeof(*p), GFP_KERNEL);
-	if (!p)
-		return -ENOMEM;
+	struct seq_file *p = file->private_data;
+
+	if (!p) {
+		p = kmalloc(sizeof(*p), GFP_KERNEL);
+		if (!p)
+			return -ENOMEM;
+		file->private_data = p;
+	}
 	memset(p, 0, sizeof(*p));
-	sema_init(&p->sem, 1);
+	mutex_init(&p->lock);
 	p->op = op;
-	file->private_data = p;
 
 	/*
 	 * Wrappers around seq_open(e.g. swaps_open) need to be
@@ -51,7 +55,10 @@ EXPORT_SYMBOL(seq_open);
 
 /**
  *	seq_read -	->read() method for sequential files.
- *	@file, @buf, @size, @ppos: see file_operations method
+ *	@file: the file to read from
+ *	@buf: the buffer to read to
+ *	@size: the maximum number of bytes to read
+ *	@ppos: the current position in the file
  *
  *	Ready-made ->f_op->read()
  */
@@ -64,7 +71,7 @@ ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
 	void *p;
 	int err = 0;
 
-	down(&m->sem);
+	mutex_lock(&m->lock);
 	/*
 	 * seq_file->op->..m_start/m_stop/m_next may do special actions
 	 * or optimisations based on the file->f_version, so we want to
@@ -157,7 +164,7 @@ Done:
 	else
 		*ppos += copied;
 	file->f_version = m->version;
-	up(&m->sem);
+	mutex_unlock(&m->lock);
 	return copied;
 Enomem:
 	err = -ENOMEM;
@@ -219,7 +226,9 @@ Eoverflow:
 
 /**
  *	seq_lseek -	->llseek() method for sequential files.
- *	@file, @offset, @origin: see file_operations method
+ *	@file: the file in question
+ *	@offset: new position
+ *	@origin: 0 for absolute, 1 for relative position
  *
  *	Ready-made ->f_op->llseek()
  */
@@ -228,7 +237,7 @@ loff_t seq_lseek(struct file *file, loff_t offset, int origin)
 	struct seq_file *m = (struct seq_file *)file->private_data;
 	long long retval = -EINVAL;
 
-	down(&m->sem);
+	mutex_lock(&m->lock);
 	m->version = file->f_version;
 	switch (origin) {
 		case 1:
@@ -251,7 +260,7 @@ loff_t seq_lseek(struct file *file, loff_t offset, int origin)
 				}
 			}
 	}
-	up(&m->sem);
+	mutex_unlock(&m->lock);
 	file->f_version = m->version;
 	return retval;
 }