[PATCH] seq_path(), /proc/mounts and /proc/swaps

This adds a new seq_...() helper:

   seq_path(seq_file, mnt, dentry, escape)

It spits the pathname into seq_file, does octal escapes for given set of
characters, returns the number of characters it'd produced or -1 in case
of error.  Long names are handled gracefully - you don't need anything
to do, generic seq_file logics will do the right thing.

/proc/mounts and /proc/swaps are converted to use of seq_path(), some
junk removed.

/proc/pid/maps will be converted next.

1 files changed, 31 insertions, 0 deletions

diff --git a/fs/seq_file.c b/fs/seq_file.c
index 98d7a01c14a4..7a9bcab37d49 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -297,6 +297,37 @@ int seq_printf(struct seq_file *m, const char *f, ...)
 	return -1;
 }
 
+int seq_path(struct seq_file *m,
+		struct vfsmount *mnt, struct dentry *dentry,
+		char *esc)
+{
+	if (m->count < m->size) {
+		char *s = m->buf + m->count;
+		char *p = d_path(dentry, mnt, s, m->size - m->count);
+		if (!IS_ERR(p)) {
+			while (s <= p) {
+				char c = *p++;
+				if (!c) {
+					p = m->buf + m->count;
+					m->count = s - m->buf;
+					return s - p;
+				} else if (!strchr(esc, c)) {
+					*s++ = c;
+				} else if (s + 4 > p) {
+					break;
+				} else {
+					*s++ = '\\';
+					*s++ = '0' + ((c & 0300) >> 6);
+					*s++ = '0' + ((c & 070) >> 3);
+					*s++ = '0' + (c & 07);
+				}
+			}
+		}
+	}
+	m->count = m->size;
+	return -1;
+}
+
 static void *single_start(struct seq_file *p, loff_t *pos)
 {
 	return NULL + (*pos == 0);