[PATCH 077/115] ion: index client->handles rbtree by buffer

John Stultz
2013-12-13T22:28:13Z

From: Colin Cross <ccross@android.com>

The only remaining users of the client->handles rbtree are
iterating through it like a list. Keep the rbtree, but change
its index to be the buffer address instead of the handle address,
which makes ion_handle_lookup a fast rbtree search.

Signed-off-by: Colin Cross <ccross@android.com>
[jstultz: modified patch to apply to staging directory]
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
drivers/staging/android/ion/ion.c | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
index ece1a4c..ef0b2d7 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -388,13 +388,16 @@ static int ion_handle_put(struct ion_handle *handle)
static struct ion_handle *ion_handle_lookup(struct ion_client *client,
struct ion_buffer *buffer)
{
- struct rb_node *n;
-
- for (n = rb_first(&client->handles); n; n = rb_next(n)) {
- struct ion_handle *handle = rb_entry(n, struct ion_handle,
- node);
- if (handle->buffer == buffer)
- return handle;
+ struct rb_node *n = client->handles.rb_node;
+
+ while (n) {
+ struct ion_handle *entry = rb_entry(n, struct ion_handle, node);
+ if (buffer < entry->buffer)
+ n = n->rb_left;
+ else if (buffer > entry->buffer)
+ n = n->rb_right;
+ else
+ return entry;
}
return ERR_PTR(-EINVAL);
}
@@ -432,9 +435,9 @@ static int ion_handle_add(struct ion_client *client, struct ion_handle *handle)
parent = *p;
entry = rb_entry(parent, struct ion_handle, node);

- if (handle < entry)
+ if (handle->buffer < entry->buffer)
p = &(*p)->rb_left;
- else if (handle > entry)
+ else if (handle->buffer > entry->buffer)
p = &(*p)->rb_right;
else
WARN(1, "%s: buffer already found.", __func__);
--
1.8.3.2