[PATCH] v9fs: zero copy implementation

Performance enhancement reducing the number of copies in the data and
stat paths.

Signed-off-by: Latchesar Ionkov <lucho@ionkov.net>
Cc: Eric Van Hensbergen <ericvh@ericvh.myip.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 15 insertions, 8 deletions

diff --git a/fs/9p/debug.h b/fs/9p/debug.h
index 4445f06919d9..fe551032788b 100644
--- a/fs/9p/debug.h
+++ b/fs/9p/debug.h
@@ -51,16 +51,23 @@ do { \
 #if DEBUG_DUMP_PKT
 static inline void dump_data(const unsigned char *data, unsigned int datalen)
 {
-        int i, j;
-        int len = datalen;
+        int i, n;
+        char buf[5*8];
 
-        printk(KERN_DEBUG "data ");
-        for (i = 0; i < len; i += 4) {
-                for (j = 0; (j < 4) && (i + j < len); j++)
-                        printk(KERN_DEBUG "%02x", data[i + j]);
-                printk(KERN_DEBUG " ");
+        n = 0;
+        i = 0;
+        while (i < datalen) {
+                n += snprintf(buf+n, sizeof(buf)-n, "%02x", data[i++]);
+                if (i%4 == 0)
+                        n += snprintf(buf+n, sizeof(buf)-n, " ");
+
+                if (i%16 == 0) {
+                        dprintk(DEBUG_ERROR, "%s\n", buf);
+                        n = 0;
+                }
         }
-        printk(KERN_DEBUG "\n");
+
+        dprintk(DEBUG_ERROR, "%s\n", buf);
 }
 #else                           /* DEBUG_DUMP_PKT */
 static inline void dump_data(const unsigned char *data, unsigned int datalen)