From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Thu, 9 Jun 2011 20:29:22 +0000 (-0400)
Subject: Return POLLERR if channel is disabled (error state)
X-Git-Tag: v2.0-pre1~55^2~1
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=254ec7bc4c72da11a4e3f2c90904b111a06a2c55;p=lttng-modules.git

Return POLLERR if channel is disabled (error state)

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/lib/ringbuffer/frontend.h b/lib/ringbuffer/frontend.h
index 85858d93..01af77a2 100644
--- a/lib/ringbuffer/frontend.h
+++ b/lib/ringbuffer/frontend.h
@@ -163,6 +163,12 @@ int lib_ring_buffer_channel_is_finalized(const struct channel *chan)
 	return chan->finalized;
 }
 
+static inline
+int lib_ring_buffer_channel_is_disabled(const struct channel *chan)
+{
+	return atomic_read(&chan->record_disabled);
+}
+
 static inline
 unsigned long lib_ring_buffer_get_read_data_size(
 				const struct lib_ring_buffer_config *config,
diff --git a/lib/ringbuffer/ring_buffer_vfs.c b/lib/ringbuffer/ring_buffer_vfs.c
index 2558ab66..fecef217 100644
--- a/lib/ringbuffer/ring_buffer_vfs.c
+++ b/lib/ringbuffer/ring_buffer_vfs.c
@@ -86,19 +86,24 @@ unsigned int lib_ring_buffer_poll(struct file *filp, poll_table *wait)
 	struct lib_ring_buffer *buf = filp->private_data;
 	struct channel *chan = buf->backend.chan;
 	const struct lib_ring_buffer_config *config = chan->backend.config;
-	int finalized;
+	int finalized, disabled;
 
 	if (filp->f_mode & FMODE_READ) {
 		init_poll_funcptr(wait, wrapper_pollwait_exclusive);
 		poll_wait(filp, &buf->read_wait, wait);
 
 		finalized = lib_ring_buffer_is_finalized(config, buf);
+		disabled = lib_ring_buffer_channel_is_disabled(chan);
+
 		/*
 		 * lib_ring_buffer_is_finalized() contains a smp_rmb() ordering
 		 * finalized load before offsets loads.
 		 */
 		WARN_ON(atomic_long_read(&buf->active_readers) != 1);
 retry:
+		if (disabled)
+			return POLLERR;
+
 		if (subbuf_trunc(lib_ring_buffer_get_offset(config, buf), chan)
 		  - subbuf_trunc(lib_ring_buffer_get_consumed(config, buf), chan)
 		  == 0) {
@@ -159,6 +164,9 @@ long lib_ring_buffer_ioctl(struct file *filp, unsigned int cmd, unsigned long ar
 	struct channel *chan = buf->backend.chan;
 	const struct lib_ring_buffer_config *config = chan->backend.config;
 
+	if (lib_ring_buffer_channel_is_disabled(chan))
+		return -EIO;
+
 	switch (cmd) {
 	case RING_BUFFER_SNAPSHOT:
 		return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot,
@@ -250,6 +258,9 @@ long lib_ring_buffer_compat_ioctl(struct file *filp, unsigned int cmd,
 	struct channel *chan = buf->backend.chan;
 	const struct lib_ring_buffer_config *config = chan->backend.config;
 
+	if (lib_ring_buffer_channel_is_disabled(chan))
+		return -EIO;
+
 	switch (cmd) {
 	case RING_BUFFER_SNAPSHOT:
 		return lib_ring_buffer_snapshot(buf, &buf->cons_snapshot,
diff --git a/ltt-debugfs-abi.c b/ltt-debugfs-abi.c
index fb6c789f..f8bee492 100644
--- a/ltt-debugfs-abi.c
+++ b/ltt-debugfs-abi.c
@@ -568,6 +568,8 @@ unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
 		poll_wait(file, channel->ops->get_hp_wait_queue(channel->chan),
 			  wait);
 
+		if (channel->ops->is_disabled(channel->chan))
+			return POLLERR;
 		if (channel->ops->is_finalized(channel->chan))
 			return POLLHUP;
 		else
diff --git a/ltt-events.h b/ltt-events.h
index 9c6fcac3..05eff540 100644
--- a/ltt-events.h
+++ b/ltt-events.h
@@ -205,6 +205,7 @@ struct ltt_channel_ops {
 	wait_queue_head_t *(*get_reader_wait_queue)(struct channel *chan);
 	wait_queue_head_t *(*get_hp_wait_queue)(struct channel *chan);
 	int (*is_finalized)(struct channel *chan);
+	int (*is_disabled)(struct channel *chan);
 };
 
 struct ltt_channel {
diff --git a/ltt-ring-buffer-client.h b/ltt-ring-buffer-client.h
index d1429785..0d8051ec 100644
--- a/ltt-ring-buffer-client.h
+++ b/ltt-ring-buffer-client.h
@@ -472,6 +472,12 @@ int ltt_is_finalized(struct channel *chan)
 	return lib_ring_buffer_channel_is_finalized(chan);
 }
 
+static
+int ltt_is_disabled(struct channel *chan)
+{
+	return lib_ring_buffer_channel_is_disabled(chan);
+}
+
 static struct ltt_transport ltt_relay_transport = {
 	.name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 	.owner = THIS_MODULE,
@@ -487,6 +493,7 @@ static struct ltt_transport ltt_relay_transport = {
 		.get_reader_wait_queue = ltt_get_reader_wait_queue,
 		.get_hp_wait_queue = ltt_get_hp_wait_queue,
 		.is_finalized = ltt_is_finalized,
+		.is_disabled = ltt_is_disabled,
 	},
 };
 
diff --git a/ltt-ring-buffer-metadata-client.h b/ltt-ring-buffer-metadata-client.h
index a687b705..8b1079d9 100644
--- a/ltt-ring-buffer-metadata-client.h
+++ b/ltt-ring-buffer-metadata-client.h
@@ -237,6 +237,12 @@ int ltt_is_finalized(struct channel *chan)
 	return lib_ring_buffer_channel_is_finalized(chan);
 }
 
+static
+int ltt_is_disabled(struct channel *chan)
+{
+	return lib_ring_buffer_channel_is_disabled(chan);
+}
+
 static struct ltt_transport ltt_relay_transport = {
 	.name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 	.owner = THIS_MODULE,
@@ -252,6 +258,7 @@ static struct ltt_transport ltt_relay_transport = {
 		.get_reader_wait_queue = ltt_get_reader_wait_queue,
 		.get_hp_wait_queue = ltt_get_hp_wait_queue,
 		.is_finalized = ltt_is_finalized,
+		.is_disabled = ltt_is_disabled,
 	},
 };