2020-11-05 18:55:00

by Deepak R Varma

Subject: [PATCH] drm/qxl: replace idr_init() by idr_init_base()

idr_init() uses base 0 which is an invalid identifier for this driver.
The idr_alloc for this driver uses 1 as start value for ID range. 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 <[email protected]>
---
drivers/gpu/drm/qxl/qxl_kms.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/qxl/qxl_kms.c b/drivers/gpu/drm/qxl/qxl_kms.c
index dc5b3850a4d4..228e2b9198f1 100644
--- a/drivers/gpu/drm/qxl/qxl_kms.c
+++ b/drivers/gpu/drm/qxl/qxl_kms.c
@@ -231,11 +231,11 @@ int qxl_device_init(struct qxl_device *qdev,
goto cursor_ring_free;
}

- idr_init(&qdev->release_idr);
+ idr_init_base(&qdev->release_idr, 1);
spin_lock_init(&qdev->release_idr_lock);
spin_lock_init(&qdev->release_lock);

- idr_init(&qdev->surf_id_idr);
+ idr_init_base(&qdev->surf_id_idr, 1);
spin_lock_init(&qdev->surf_id_idr_lock);

mutex_init(&qdev->async_io_mutex);
--
2.25.1

2020-11-06 08:26:38

by Gerd Hoffmann

Subject: Re: [PATCH] drm/qxl: replace idr_init() by idr_init_base()

On Fri, Nov 06, 2020 at 12:20:16AM +0530, Deepak R Varma wrote:
> idr_init() uses base 0 which is an invalid identifier for this driver.
> The idr_alloc for this driver uses 1 as start value for ID range. 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 <[email protected]>

Pushed to drm-misc-next.

thanks,
Gerd