[PATCH -next] drm: Fix error handling in drm_legacy_addctx

From: YueHaibing
Date: Fri Dec 28 2018 - 21:50:05 EST


'ctx->handle' is unsigned, it never less than zero.
This patch use int 'tmp_handle' to handle the err condition.

Fixes: 62968144e673 ("drm: convert drm context code to use Linux idr")
Signed-off-by: YueHaibing <yuehaibing@xxxxxxxxxx>
---
drivers/gpu/drm/drm_context.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_context.c b/drivers/gpu/drm/drm_context.c
index 506663c..8e73fab 100644
--- a/drivers/gpu/drm/drm_context.c
+++ b/drivers/gpu/drm/drm_context.c
@@ -361,23 +361,26 @@ int drm_legacy_addctx(struct drm_device *dev, void *data,
{
struct drm_ctx_list *ctx_entry;
struct drm_ctx *ctx = data;
+ int tmp_handle;

if (!drm_core_check_feature(dev, DRIVER_KMS_LEGACY_CONTEXT) &&
!drm_core_check_feature(dev, DRIVER_LEGACY))
return -EOPNOTSUPP;

- ctx->handle = drm_legacy_ctxbitmap_next(dev);
- if (ctx->handle == DRM_KERNEL_CONTEXT) {
+ tmp_handle = drm_legacy_ctxbitmap_next(dev);
+ if (tmp_handle == DRM_KERNEL_CONTEXT) {
/* Skip kernel's context and get a new one. */
- ctx->handle = drm_legacy_ctxbitmap_next(dev);
+ tmp_handle = drm_legacy_ctxbitmap_next(dev);
}
- DRM_DEBUG("%d\n", ctx->handle);
- if (ctx->handle < 0) {
+ DRM_DEBUG("%d\n", tmp_handle);
+ if (tmp_handle < 0) {
DRM_DEBUG("Not enough free contexts.\n");
/* Should this return -EBUSY instead? */
- return -ENOMEM;
+ return tmp_handle;
}

+ ctx->handle = tmp_handle;
+
ctx_entry = kmalloc(sizeof(*ctx_entry), GFP_KERNEL);
if (!ctx_entry) {
DRM_DEBUG("out of memory\n");
--
2.7.0