[PATCH 3/9] firewire: cdev: add context analysis annotations for isochronous context

[Takashi Sakamoto]

A client can operate on a single isochronous context at a time. A mutex
is used to ensure exclusive access to the context.

Use guard annotations to describe the synchronization requirements for
accessing the context.

Signed-off-by: Takashi Sakamoto <o-takashi@xxxxxxxxxxxxx>
---
 drivers/firewire/core-cdev.c | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c
index 512afa589e2e..418b72cb8835 100644
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -62,7 +62,7 @@ struct client {
 	wait_queue_head_t tx_flush_wait;
 	u64 bus_reset_closure;
 
-	struct fw_iso_context *iso_context;
+	struct fw_iso_context *iso_context __pt_guarded_by(iso_context_mutex);
 	struct mutex iso_context_mutex;
 	u64 iso_closure;
 	struct fw_iso_buffer buffer;
@@ -1129,8 +1129,11 @@ static int ioctl_create_iso_context(struct client *client, union ioctl_arg *arg)
 static int ioctl_set_iso_channels(struct client *client, union ioctl_arg *arg)
 {
 	struct fw_cdev_set_iso_channels *a = &arg->set_iso_channels;
-	struct fw_iso_context *ctx = client->iso_context;
+	struct fw_iso_context *ctx;
 
+	guard(mutex)(&client->iso_context_mutex);
+
+	ctx = client->iso_context;
 	if (ctx == NULL || a->handle != 0)
 		return -EINVAL;
 
@@ -1149,12 +1152,15 @@ static int ioctl_queue_iso(struct client *client, union ioctl_arg *arg)
 {
 	struct fw_cdev_queue_iso *a = &arg->queue_iso;
 	struct fw_cdev_iso_packet __user *p, *end, *next;
-	struct fw_iso_context *ctx = client->iso_context;
+	struct fw_iso_context *ctx;
 	unsigned long payload, buffer_end, transmit_header_bytes = 0;
 	u32 control;
 	int count;
 	DEFINE_RAW_FLEX(struct fw_iso_packet, u, header, 64);
 
+	guard(mutex)(&client->iso_context_mutex);
+
+	ctx = client->iso_context;
 	if (ctx == NULL || a->handle != 0)
 		return -EINVAL;
 
@@ -1252,6 +1258,8 @@ static int ioctl_start_iso(struct client *client, union ioctl_arg *arg)
 	    FW_CDEV_ISO_CONTEXT_MATCH_TAG3 != FW_ISO_CONTEXT_MATCH_TAG3 ||
 	    FW_CDEV_ISO_CONTEXT_MATCH_ALL_TAGS != FW_ISO_CONTEXT_MATCH_ALL_TAGS);
 
+	guard(mutex)(&client->iso_context_mutex);
+
 	if (client->iso_context == NULL || a->handle != 0)
 		return -EINVAL;
 
@@ -1267,6 +1275,8 @@ static int ioctl_stop_iso(struct client *client, union ioctl_arg *arg)
 {
 	struct fw_cdev_stop_iso *a = &arg->stop_iso;
 
+	guard(mutex)(&client->iso_context_mutex);
+
 	if (client->iso_context == NULL || a->handle != 0)
 		return -EINVAL;
 
@@ -1277,6 +1287,8 @@ static int ioctl_flush_iso(struct client *client, union ioctl_arg *arg)
 {
 	struct fw_cdev_flush_iso *a = &arg->flush_iso;
 
+	guard(mutex)(&client->iso_context_mutex);
+
 	if (client->iso_context == NULL || a->handle != 0)
 		return -EINVAL;
 
@@ -1937,8 +1949,10 @@ static int fw_device_op_release(struct inode *inode, struct file *file)
 	scoped_guard(mutex, &client->device->client_list_mutex)
 		list_del(&client->link);
 
-	if (client->iso_context)
-		fw_iso_context_destroy(client->iso_context);
+	scoped_guard(mutex, &client->iso_context_mutex) {
+		if (client->iso_context)
+			fw_iso_context_destroy(client->iso_context);
+	}
 	mutex_destroy(&client->iso_context_mutex);
 
 	if (client->buffer.pages)
-- 
2.53.0