firewire: cdev: add ioctls for manual iso resource management

This adds ioctls for allocation and deallocation of a channel or/and
bandwidth without auto-reallocation and without auto-deallocation.

The benefit of these ioctls is that libraw1394-style isochronous
resource management can be implemented without write access to the IRM's
character device file.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

1 files changed, 54 insertions, 13 deletions

diff --git a/drivers/firewire/fw-cdev.c b/drivers/firewire/fw-cdev.c
index a227853aa1e..08fe68d34f3 100644
--- a/drivers/firewire/fw-cdev.c
+++ b/drivers/firewire/fw-cdev.c
@@ -121,14 +121,15 @@ struct iso_resource {
         struct client *client;
         /* Schedule work and access todo only with client->lock held. */
         struct delayed_work work;
-        enum {ISO_RES_ALLOC, ISO_RES_REALLOC, ISO_RES_DEALLOC,} todo;
+        enum {ISO_RES_ALLOC, ISO_RES_REALLOC, ISO_RES_DEALLOC,
+              ISO_RES_ALLOC_ONCE, ISO_RES_DEALLOC_ONCE,} todo;
         int generation;
         u64 channels;
         s32 bandwidth;
         struct iso_resource_event *e_alloc, *e_dealloc;
 };
 
-static void schedule_iso_resource(struct iso_resource *);
+static int schedule_iso_resource(struct iso_resource *);
 static void release_iso_resource(struct client *, struct client_resource *);
 
 /*
@@ -1033,7 +1034,9 @@ static void iso_resource_work(struct work_struct *work)
                 skip = todo == ISO_RES_REALLOC &&
                        r->generation == generation;
         }
-        free = todo == ISO_RES_DEALLOC;
+        free = todo == ISO_RES_DEALLOC ||
+               todo == ISO_RES_ALLOC_ONCE ||
+               todo == ISO_RES_DEALLOC_ONCE;
         r->generation = generation;
         spin_unlock_irq(&client->lock);
 
@@ -1044,7 +1047,9 @@ static void iso_resource_work(struct work_struct *work)
 
         fw_iso_resource_manage(client->device->card, generation,
                         r->channels, &channel, &bandwidth,
-                        todo == ISO_RES_ALLOC || todo == ISO_RES_REALLOC);
+                        todo == ISO_RES_ALLOC ||
+                        todo == ISO_RES_REALLOC ||
+                        todo == ISO_RES_ALLOC_ONCE);
         /*
          * Is this generation outdated already?  As long as this resource sticks
          * in the idr, it will be scheduled again for a newer generation or at
@@ -1082,7 +1087,7 @@ static void iso_resource_work(struct work_struct *work)
         if (todo == ISO_RES_REALLOC && success)
                 goto out;
 
-        if (todo == ISO_RES_ALLOC) {
+        if (todo == ISO_RES_ALLOC || todo == ISO_RES_ALLOC_ONCE) {
                 e = r->e_alloc;
                 r->e_alloc = NULL;
         } else {
@@ -1106,10 +1111,17 @@ static void iso_resource_work(struct work_struct *work)
         client_put(client);
 }
 
-static void schedule_iso_resource(struct iso_resource *r)
+static int schedule_iso_resource(struct iso_resource *r)
 {
-        if (schedule_delayed_work(&r->work, 0))
-                client_get(r->client);
+        int scheduled;
+
+        client_get(r->client);
+
+        scheduled = schedule_delayed_work(&r->work, 0);
+        if (!scheduled)
+                client_put(r->client);
+
+        return scheduled;
 }
 
 static void release_iso_resource(struct client *client,
@@ -1124,9 +1136,9 @@ static void release_iso_resource(struct client *client,
         spin_unlock_irq(&client->lock);
 }
 
-static int ioctl_allocate_iso_resource(struct client *client, void *buffer)
+static int init_iso_resource(struct client *client,
+                struct fw_cdev_allocate_iso_resource *request, int todo)
 {
-        struct fw_cdev_allocate_iso_resource *request = buffer;
         struct iso_resource_event *e1, *e2;
         struct iso_resource *r;
         int ret;
@@ -1146,7 +1158,7 @@ static int ioctl_allocate_iso_resource(struct client *client, void *buffer)
 
         INIT_DELAYED_WORK(&r->work, iso_resource_work);
         r->client       = client;
-        r->todo         = ISO_RES_ALLOC;
+        r->todo         = todo;
         r->generation   = -1;
         r->channels     = request->channels;
         r->bandwidth    = request->bandwidth;
@@ -1158,8 +1170,14 @@ static int ioctl_allocate_iso_resource(struct client *client, void *buffer)
         e2->resource.closure    = request->closure;
         e2->resource.type       = FW_CDEV_EVENT_ISO_RESOURCE_DEALLOCATED;
 
-        r->resource.release = release_iso_resource;
-        ret = add_client_resource(client, &r->resource, GFP_KERNEL);
+        if (todo == ISO_RES_ALLOC) {
+                r->resource.release = release_iso_resource;
+                ret = add_client_resource(client, &r->resource, GFP_KERNEL);
+        } else {
+                r->resource.release = NULL;
+                r->resource.handle = -1;
+                ret = schedule_iso_resource(r) ? 0 : -ENOMEM;
+        }
         if (ret < 0)
                 goto fail;
         request->handle = r->resource.handle;
@@ -1173,6 +1191,13 @@ static int ioctl_allocate_iso_resource(struct client *client, void *buffer)
         return ret;
 }
 
+static int ioctl_allocate_iso_resource(struct client *client, void *buffer)
+{
+        struct fw_cdev_allocate_iso_resource *request = buffer;
+
+        return init_iso_resource(client, request, ISO_RES_ALLOC);
+}
+
 static int ioctl_deallocate_iso_resource(struct client *client, void *buffer)
 {
         struct fw_cdev_deallocate *request = buffer;
@@ -1181,6 +1206,20 @@ static int ioctl_deallocate_iso_resource(struct client *client, void *buffer)
                                        release_iso_resource, NULL);
 }
 
+static int ioctl_allocate_iso_resource_once(struct client *client, void *buffer)
+{
+        struct fw_cdev_allocate_iso_resource *request = buffer;
+
+        return init_iso_resource(client, request, ISO_RES_ALLOC_ONCE);
+}
+
+static int ioctl_deallocate_iso_resource_once(struct client *client, void *buffer)
+{
+        struct fw_cdev_allocate_iso_resource *request = buffer;
+
+        return init_iso_resource(client, request, ISO_RES_DEALLOC_ONCE);
+}
+
 static int (* const ioctl_handlers[])(struct client *client, void *buffer) = {
         ioctl_get_info,
         ioctl_send_request,
@@ -1197,6 +1236,8 @@ static int (* const ioctl_handlers[])(struct client *client, void *buffer) = {
         ioctl_get_cycle_timer,
         ioctl_allocate_iso_resource,
         ioctl_deallocate_iso_resource,
+        ioctl_allocate_iso_resource_once,
+        ioctl_deallocate_iso_resource_once,
 };
 
 static int dispatch_ioctl(struct client *client,