[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>
diff --git a/fs/9p/9p.h b/fs/9p/9p.h
index 6355392..007ff63 100644
--- a/fs/9p/9p.h
+++ b/fs/9p/9p.h
@@ -3,6 +3,7 @@
*
* 9P protocol definitions.
*
+ * Copyright (C) 2005 by Latchesar Ionkov <lucho@ionkov.net>
* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
*
@@ -102,10 +103,16 @@
#define V9FS_NOTAG (u16)(~0)
#define V9FS_NOFID (u32)(~0)
+#define V9FS_MAXWELEM 16
/* ample room for Twrite/Rread header (iounit) */
#define V9FS_IOHDRSZ 24
+struct v9fs_str {
+ u16 len;
+ char *str;
+};
+
/* qids are the unique ID for a file (like an inode */
struct v9fs_qid {
u8 type;
@@ -123,6 +130,29 @@
u32 atime;
u32 mtime;
u64 length;
+ struct v9fs_str name;
+ struct v9fs_str uid;
+ struct v9fs_str gid;
+ struct v9fs_str muid;
+ struct v9fs_str extension; /* 9p2000.u extensions */
+ u32 n_uid; /* 9p2000.u extensions */
+ u32 n_gid; /* 9p2000.u extensions */
+ u32 n_muid; /* 9p2000.u extensions */
+};
+
+/* file metadata (stat) structure used to create Twstat message
+ The is similar to v9fs_stat, but the strings don't point to
+ the same memory block and should be freed separately
+*/
+struct v9fs_wstat {
+ u16 size;
+ u16 type;
+ u32 dev;
+ struct v9fs_qid qid;
+ u32 mode;
+ u32 atime;
+ u32 mtime;
+ u64 length;
char *name;
char *uid;
char *gid;
@@ -131,25 +161,24 @@
u32 n_uid; /* 9p2000.u extensions */
u32 n_gid; /* 9p2000.u extensions */
u32 n_muid; /* 9p2000.u extensions */
- char data[0];
};
/* Structures for Protocol Operations */
struct Tversion {
u32 msize;
- char *version;
+ struct v9fs_str version;
};
struct Rversion {
u32 msize;
- char *version;
+ struct v9fs_str version;
};
struct Tauth {
u32 afid;
- char *uname;
- char *aname;
+ struct v9fs_str uname;
+ struct v9fs_str aname;
};
struct Rauth {
@@ -157,12 +186,12 @@
};
struct Rerror {
- char *error;
+ struct v9fs_str error;
u32 errno; /* 9p2000.u extension */
};
struct Tflush {
- u32 oldtag;
+ u16 oldtag;
};
struct Rflush {
@@ -171,8 +200,8 @@
struct Tattach {
u32 fid;
u32 afid;
- char *uname;
- char *aname;
+ struct v9fs_str uname;
+ struct v9fs_str aname;
};
struct Rattach {
@@ -182,13 +211,13 @@
struct Twalk {
u32 fid;
u32 newfid;
- u32 nwname;
- char **wnames;
+ u16 nwname;
+ struct v9fs_str wnames[16];
};
struct Rwalk {
- u32 nwqid;
- struct v9fs_qid *wqids;
+ u16 nwqid;
+ struct v9fs_qid wqids[16];
};
struct Topen {
@@ -203,7 +232,7 @@
struct Tcreate {
u32 fid;
- char *name;
+ struct v9fs_str name;
u32 perm;
u8 mode;
};
@@ -254,12 +283,12 @@
};
struct Rstat {
- struct v9fs_stat *stat;
+ struct v9fs_stat stat;
};
struct Twstat {
u32 fid;
- struct v9fs_stat *stat;
+ struct v9fs_stat stat;
};
struct Rwstat {
@@ -274,6 +303,7 @@
u32 size;
u8 id;
u16 tag;
+ void *sdata;
union {
struct Tversion tversion;
@@ -306,10 +336,12 @@
} params;
};
-#define V9FS_FCALLHDRSZ (sizeof(struct v9fs_fcall) + \
- sizeof(struct v9fs_stat) + 16*sizeof(struct v9fs_qid) + 16)
+#define PRINT_FCALL_ERROR(s, fcall) dprintk(DEBUG_ERROR, "%s: %.*s\n", s, \
+ fcall?fcall->params.rerror.error.len:0, \
+ fcall?fcall->params.rerror.error.str:"");
-#define FCALL_ERROR(fcall) (fcall ? fcall->params.rerror.error : "")
+char *v9fs_str_copy(char *buf, int buflen, struct v9fs_str *str);
+int v9fs_str_compare(char *buf, struct v9fs_str *str);
int v9fs_t_version(struct v9fs_session_info *v9ses, u32 msize,
char *version, struct v9fs_fcall **rcall);
@@ -325,7 +357,7 @@
struct v9fs_fcall **rcall);
int v9fs_t_wstat(struct v9fs_session_info *v9ses, u32 fid,
- struct v9fs_stat *stat, struct v9fs_fcall **rcall);
+ struct v9fs_wstat *wstat, struct v9fs_fcall **rcall);
int v9fs_t_walk(struct v9fs_session_info *v9ses, u32 fid, u32 newfid,
char *name, struct v9fs_fcall **rcall);
@@ -343,4 +375,5 @@
u64 offset, u32 count, struct v9fs_fcall **rcall);
int v9fs_t_write(struct v9fs_session_info *v9ses, u32 fid, u64 offset,
- u32 count, void *data, struct v9fs_fcall **rcall);
+ u32 count, const char __user * data,
+ struct v9fs_fcall **rcall);