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Subject[PATCH v2] staging: bcm2835-camera: Replace open-coded idr with a struct idr.
Date
We just need some integer handles that can map back to our message
struct when we're handling a reply, which struct idr is perfect for.

v2: Fix error check to look at the right variable.

Signed-off-by: Eric Anholt <eric@anholt.net>
---
.../vc04_services/bcm2835-camera/mmal-vchiq.c | 135 ++++--------------
1 file changed, 31 insertions(+), 104 deletions(-)

diff --git a/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c b/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c
index 3a3b843fc122..f5b5ead6347c 100644
--- a/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c
+++ b/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c
@@ -21,7 +21,6 @@
#include <linux/slab.h>
#include <linux/completion.h>
#include <linux/vmalloc.h>
-#include <linux/btree.h>
#include <asm/cacheflush.h>
#include <media/videobuf2-vmalloc.h>

@@ -111,7 +110,11 @@ struct vchiq_mmal_instance;
/* normal message context */
struct mmal_msg_context {
struct vchiq_mmal_instance *instance;
- u32 handle;
+
+ /* Index in the context_map idr so that we can find the
+ * mmal_msg_context again when servicing the VCHI reply.
+ */
+ int handle;

union {
struct {
@@ -149,13 +152,6 @@ struct mmal_msg_context {

};

-struct vchiq_mmal_context_map {
- /* ensure serialized access to the btree(contention should be low) */
- struct mutex lock;
- struct btree_head32 btree_head;
- u32 last_handle;
-};
-
struct vchiq_mmal_instance {
VCHI_SERVICE_HANDLE_T handle;

@@ -165,92 +161,19 @@ struct vchiq_mmal_instance {
/* vmalloc page to receive scratch bulk xfers into */
void *bulk_scratch;

- /* mapping table between context handles and mmal_msg_contexts */
- struct vchiq_mmal_context_map context_map;
+ struct idr context_map;
+ spinlock_t context_map_lock;

/* component to use next */
int component_idx;
struct vchiq_mmal_component component[VCHIQ_MMAL_MAX_COMPONENTS];
};

-static int __must_check
-mmal_context_map_init(struct vchiq_mmal_context_map *context_map)
-{
- mutex_init(&context_map->lock);
- context_map->last_handle = 0;
- return btree_init32(&context_map->btree_head);
-}
-
-static void mmal_context_map_destroy(struct vchiq_mmal_context_map *context_map)
-{
- mutex_lock(&context_map->lock);
- btree_destroy32(&context_map->btree_head);
- mutex_unlock(&context_map->lock);
-}
-
-static u32
-mmal_context_map_create_handle(struct vchiq_mmal_context_map *context_map,
- struct mmal_msg_context *msg_context,
- gfp_t gfp)
-{
- u32 handle;
-
- mutex_lock(&context_map->lock);
-
- while (1) {
- /* just use a simple count for handles, but do not use 0 */
- context_map->last_handle++;
- if (!context_map->last_handle)
- context_map->last_handle++;
-
- handle = context_map->last_handle;
-
- /* check if the handle is already in use */
- if (!btree_lookup32(&context_map->btree_head, handle))
- break;
- }
-
- if (btree_insert32(&context_map->btree_head, handle,
- msg_context, gfp)) {
- /* probably out of memory */
- mutex_unlock(&context_map->lock);
- return 0;
- }
-
- mutex_unlock(&context_map->lock);
- return handle;
-}
-
-static struct mmal_msg_context *
-mmal_context_map_lookup_handle(struct vchiq_mmal_context_map *context_map,
- u32 handle)
-{
- struct mmal_msg_context *msg_context;
-
- if (!handle)
- return NULL;
-
- mutex_lock(&context_map->lock);
-
- msg_context = btree_lookup32(&context_map->btree_head, handle);
-
- mutex_unlock(&context_map->lock);
- return msg_context;
-}
-
-static void
-mmal_context_map_destroy_handle(struct vchiq_mmal_context_map *context_map,
- u32 handle)
-{
- mutex_lock(&context_map->lock);
- btree_remove32(&context_map->btree_head, handle);
- mutex_unlock(&context_map->lock);
-}
-
static struct mmal_msg_context *
get_msg_context(struct vchiq_mmal_instance *instance)
{
struct mmal_msg_context *msg_context;
+ int handle;

/* todo: should this be allocated from a pool to avoid kzalloc */
msg_context = kzalloc(sizeof(*msg_context), GFP_KERNEL);
@@ -258,32 +181,40 @@ get_msg_context(struct vchiq_mmal_instance *instance)
if (!msg_context)
return ERR_PTR(-ENOMEM);

- msg_context->instance = instance;
- msg_context->handle =
- mmal_context_map_create_handle(&instance->context_map,
- msg_context,
- GFP_KERNEL);
+ /* Create an ID that will be passed along with our message so
+ * that when we service the VCHI reply, we can look up what
+ * message is being replied to.
+ */
+ spin_lock(&instance->context_map_lock);
+ handle = idr_alloc(&instance->context_map, msg_context,
+ 0, 0, GFP_KERNEL);
+ spin_unlock(&instance->context_map_lock);

- if (!msg_context->handle) {
+ if (handle < 0) {
kfree(msg_context);
- return ERR_PTR(-ENOMEM);
+ return ERR_PTR(handle);
}

+ msg_context->instance = instance;
+ msg_context->handle = handle;
+
return msg_context;
}

static struct mmal_msg_context *
-lookup_msg_context(struct vchiq_mmal_instance *instance, u32 handle)
+lookup_msg_context(struct vchiq_mmal_instance *instance, int handle)
{
- return mmal_context_map_lookup_handle(&instance->context_map,
- handle);
+ return idr_find(&instance->context_map, handle);
}

static void
release_msg_context(struct mmal_msg_context *msg_context)
{
- mmal_context_map_destroy_handle(&msg_context->instance->context_map,
- msg_context->handle);
+ struct vchiq_mmal_instance *instance = msg_context->instance;
+
+ spin_lock(&instance->context_map_lock);
+ idr_remove(&instance->context_map, msg_context->handle);
+ spin_unlock(&instance->context_map_lock);
kfree(msg_context);
}

@@ -1860,7 +1791,7 @@ int vchiq_mmal_finalise(struct vchiq_mmal_instance *instance)

vfree(instance->bulk_scratch);

- mmal_context_map_destroy(&instance->context_map);
+ idr_destroy(&instance->context_map);

kfree(instance);

@@ -1922,12 +1853,8 @@ int vchiq_mmal_init(struct vchiq_mmal_instance **out_instance)

instance->bulk_scratch = vmalloc(PAGE_SIZE);

- status = mmal_context_map_init(&instance->context_map);
- if (status) {
- pr_err("Failed to init context map (status=%d)\n", status);
- kfree(instance);
- return status;
- }
+ spin_lock_init(&instance->context_map_lock);
+ idr_init_base(&instance->context_map, 1);

params.callback_param = instance;

--
2.17.0
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