[PATCH v2] drm/vc4: replace idr_init() by idr_init_base()

Deepak R Varma
2020-11-05T20:21:46Z

idr_init() uses base 0 which is an invalid identifier for this driver.
The idr_alloc for this driver uses VC4_PERFMONID_MIN as start value for
ID range and it is #defined to 1. The new function idr_init_base allows
IDR to set the ID lookup from base 1. This avoids all lookups that
otherwise starts from 0 since 0 is always unused / available.

References: commit 6ce711f27500 ("idr: Make 1-based IDRs more efficient")

Signed-off-by: Deepak R Varma <mh12gx2825@gmail.com>
---
Changes since v1:
- Change suggested by Eric Anholt
1. Use VC4_PERFMONID_MIN instead of magic number 1

drivers/gpu/drm/vc4/vc4_perfmon.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vc4/vc4_perfmon.c b/drivers/gpu/drm/vc4/vc4_perfmon.c
index f4aa75efd16b..18abc06335c1 100644
--- a/drivers/gpu/drm/vc4/vc4_perfmon.c
+++ b/drivers/gpu/drm/vc4/vc4_perfmon.c
@@ -77,7 +77,7 @@ struct vc4_perfmon *vc4_perfmon_find(struct vc4_file *vc4file, int id)
void vc4_perfmon_open_file(struct vc4_file *vc4file)
{
mutex_init(&vc4file->perfmon.lock);
- idr_init(&vc4file->perfmon.idr);
+ idr_init_base(&vc4file->perfmon.idr, VC4_PERFMONID_MIN);
}

static int vc4_perfmon_idr_del(int id, void *elem, void *data)
--
2.25.1