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Date: Tue, 23 Sep 2008 00:27:56 -0500
From: Tom Zanussi <zanussi@...cast.net>
To: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: prasad@...ux.vnet.ibm.com, Martin Bligh <mbligh@...gle.com>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Thomas Gleixner <tglx@...utronix.de>,
Mathieu Desnoyers <compudj@...stal.dyndns.org>,
Steven Rostedt <rostedt@...dmis.org>, od@...ell.com,
"Frank Ch. Eigler" <fche@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>, hch@....de,
David Wilder <dwilder@...ibm.com>
Subject: [PATCH 3/3] relay - add channel flags
Add channel flags to relay, remove global callback param.
relay should probably have had a flags param from the beginning; it
wasn't originally added because it wasn't originally needed - it
probably would have helped avoid some of the callback contortions
that were added due to a lack of flags. This adds them and does a
small amount of low-hanging cleanup, and is also in preparation for
some new flags in future patches.
Signed-off-by: Tom Zanussi <tzanussi@...il.com>
diff --git a/block/blktrace.c b/block/blktrace.c
index eb9651c..150c5f7 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -356,8 +356,7 @@ static int blk_remove_buf_file_callback(struct dentry *dentry)
static struct dentry *blk_create_buf_file_callback(const char *filename,
struct dentry *parent,
int mode,
- struct rchan_buf *buf,
- int *is_global)
+ struct rchan_buf *buf)
{
return debugfs_create_file(filename, mode, parent, buf,
&relay_file_operations);
@@ -424,7 +423,7 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
goto err;
bt->rchan = relay_open("trace", dir, buts->buf_size,
- buts->buf_nr, &blk_relay_callbacks, bt);
+ buts->buf_nr, &blk_relay_callbacks, bt, 0UL);
if (!bt->rchan)
goto err;
diff --git a/include/linux/relay.h b/include/linux/relay.h
index 52e4d61..18fd269 100644
--- a/include/linux/relay.h
+++ b/include/linux/relay.h
@@ -25,7 +25,13 @@
/*
* Tracks changes to rchan/rchan_buf structs
*/
-#define RELAYFS_CHANNEL_VERSION 7
+#define RELAYFS_CHANNEL_VERSION 8
+
+/*
+ * relay channel flags
+ */
+#define RCHAN_MODE_OVERWRITE 0x00000001 /* 'flight' mode */
+#define RCHAN_GLOBAL_BUFFER 0x00000002 /* not using per-cpu */
/*
* Per-cpu relay channel buffer
@@ -66,11 +72,11 @@ struct rchan
void *private_data; /* for user-defined data */
size_t last_toobig; /* tried to log event > subbuf size */
struct rchan_buf *buf[NR_CPUS]; /* per-cpu channel buffers */
- int is_global; /* One global buffer ? */
struct list_head list; /* for channel list */
struct dentry *parent; /* parent dentry passed to open */
int has_base_filename; /* has a filename associated? */
char base_filename[NAME_MAX]; /* saved base filename */
+ unsigned long flags; /* relay flags for this channel */
};
/*
@@ -125,7 +131,6 @@ struct rchan_callbacks
* @parent: the parent of the file to create
* @mode: the mode of the file to create
* @buf: the channel buffer
- * @is_global: outparam - set non-zero if the buffer should be global
*
* Called during relay_open(), once for each per-cpu buffer,
* to allow the client to create a file to be used to
@@ -136,17 +141,12 @@ struct rchan_callbacks
* The callback should return the dentry of the file created
* to represent the relay buffer.
*
- * Setting the is_global outparam to a non-zero value will
- * cause relay_open() to create a single global buffer rather
- * than the default set of per-cpu buffers.
- *
* See Documentation/filesystems/relayfs.txt for more info.
*/
struct dentry *(*create_buf_file)(const char *filename,
struct dentry *parent,
int mode,
- struct rchan_buf *buf,
- int *is_global);
+ struct rchan_buf *buf);
/*
* remove_buf_file - remove file representing a relay channel buffer
@@ -191,7 +191,8 @@ struct rchan *relay_open(const char *base_filename,
size_t subbuf_size,
size_t n_subbufs,
struct rchan_callbacks *cb,
- void *private_data);
+ void *private_data,
+ unsigned long rchan_flags);
extern int relay_late_setup_files(struct rchan *chan,
const char *base_filename,
struct dentry *parent);
diff --git a/kernel/relay.c b/kernel/relay.c
index e299f49..a2e06b0 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -310,8 +310,7 @@ static void buf_unmapped_default_callback(struct rchan_buf *buf,
static struct dentry *create_buf_file_default_callback(const char *filename,
struct dentry *parent,
int mode,
- struct rchan_buf *buf,
- int *is_global)
+ struct rchan_buf *buf)
{
return NULL;
}
@@ -411,7 +410,7 @@ void relay_reset(struct rchan *chan)
if (!chan)
return;
- if (chan->is_global && chan->buf[0]) {
+ if (chan->flags & RCHAN_GLOBAL_BUFFER && chan->buf[0]) {
__relay_reset(chan->buf[0], 0);
return;
}
@@ -445,8 +444,7 @@ static struct dentry *relay_create_buf_file(struct rchan *chan,
/* Create file in fs */
dentry = chan->cb->create_buf_file(tmpname, chan->parent,
- S_IRUSR, buf,
- &chan->is_global);
+ S_IRUSR, buf);
kfree(tmpname);
@@ -463,7 +461,7 @@ static struct rchan_buf *relay_open_buf(struct rchan *chan, unsigned int cpu)
struct rchan_buf *buf = NULL;
struct dentry *dentry;
- if (chan->is_global)
+ if (chan->flags & RCHAN_GLOBAL_BUFFER)
return chan->buf[0];
buf = relay_create_buf(chan);
@@ -480,7 +478,7 @@ static struct rchan_buf *relay_open_buf(struct rchan *chan, unsigned int cpu)
buf->cpu = cpu;
__relay_reset(buf, 1);
- if(chan->is_global) {
+ if(chan->flags & RCHAN_GLOBAL_BUFFER) {
chan->buf[0] = buf;
buf->cpu = 0;
}
@@ -595,7 +593,8 @@ struct rchan *relay_open(const char *base_filename,
size_t subbuf_size,
size_t n_subbufs,
struct rchan_callbacks *cb,
- void *private_data)
+ void *private_data,
+ unsigned long rchan_flags)
{
unsigned int i;
struct rchan *chan;
@@ -612,6 +611,7 @@ struct rchan *relay_open(const char *base_filename,
chan->subbuf_size = subbuf_size;
chan->alloc_size = FIX_SIZE(subbuf_size * n_subbufs);
chan->parent = parent;
+ chan->flags = rchan_flags;
chan->private_data = private_data;
if (base_filename) {
chan->has_base_filename = 1;
@@ -828,7 +828,7 @@ void relay_close(struct rchan *chan)
return;
mutex_lock(&relay_channels_mutex);
- if (chan->is_global && chan->buf[0])
+ if (chan->flags & RCHAN_GLOBAL_BUFFER && chan->buf[0])
relay_close_buf(chan->buf[0]);
else
for_each_possible_cpu(i)
@@ -859,7 +859,7 @@ void relay_flush(struct rchan *chan)
if (!chan)
return;
- if (chan->is_global && chan->buf[0]) {
+ if (chan->flags & RCHAN_GLOBAL_BUFFER && chan->buf[0]) {
chan->cb->switch_subbuf(chan->buf[0], 0);
return;
}
diff --git a/virt/kvm/kvm_trace.c b/virt/kvm/kvm_trace.c
index 58141f3..d0a9e1c 100644
--- a/virt/kvm/kvm_trace.c
+++ b/virt/kvm/kvm_trace.c
@@ -130,10 +130,9 @@ static int kvm_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
}
static struct dentry *kvm_create_buf_file_callack(const char *filename,
- struct dentry *parent,
- int mode,
- struct rchan_buf *buf,
- int *is_global)
+ struct dentry *parent,
+ int mode,
+ struct rchan_buf *buf)
{
return debugfs_create_file(filename, mode, parent, buf,
&relay_file_operations);
@@ -171,7 +170,7 @@ static int do_kvm_trace_enable(struct kvm_user_trace_setup *kuts)
goto err;
kt->rchan = relay_open("trace", kvm_debugfs_dir, kuts->buf_size,
- kuts->buf_nr, &kvm_relay_callbacks, kt);
+ kuts->buf_nr, &kvm_relay_callbacks, kt, 0UL);
if (!kt->rchan)
goto err;
--
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