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Subject[PATCH 1/3] drm/i915: allocate mock file pointer dynamically
Date
A struct file is a bit too large to put on the kernel stack in general
and triggers a warning for low settings of CONFIG_FRAME_WARN:

drivers/gpu/drm/i915/selftests/mock_drm.c: In function 'mock_file':
drivers/gpu/drm/i915/selftests/mock_drm.c:46:1: error: the frame size of 1328 bytes is larger than 1280 bytes [-Werror=frame-larger-than=]
drivers/gpu/drm/i915/selftests/mock_drm.c: In function 'mock_file_free':
drivers/gpu/drm/i915/selftests/mock_drm.c:54:1: error: the frame size of 1312 bytes is larger than 1280 bytes [-Werror=frame-larger-than=]

It's also slightly dangerous to leave a reference to a stack object
in the drm_file structure after leaving the stack frame.
This changes the code to just allocate the object dynamically
and release it when we are done with it.

Fixes: 66d9cb5d805a ("drm/i915: Mock the GEM device for self-testing")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/gpu/drm/i915/selftests/mock_drm.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/selftests/mock_drm.c b/drivers/gpu/drm/i915/selftests/mock_drm.c
index 113dec05c7dc..18514065c93d 100644
--- a/drivers/gpu/drm/i915/selftests/mock_drm.c
+++ b/drivers/gpu/drm/i915/selftests/mock_drm.c
@@ -32,15 +32,15 @@ static inline struct inode fake_inode(struct drm_i915_private *i915)
struct drm_file *mock_file(struct drm_i915_private *i915)
{
struct inode inode = fake_inode(i915);
- struct file filp = {};
+ struct file *filp = kzalloc(sizeof(struct file), GFP_KERNEL);
struct drm_file *file;
int err;

- err = drm_open(&inode, &filp);
+ err = drm_open(&inode, filp);
if (unlikely(err))
return ERR_PTR(err);

- file = filp.private_data;
+ file = filp->private_data;
file->authenticated = true;
return file;
}
@@ -48,7 +48,9 @@ struct drm_file *mock_file(struct drm_i915_private *i915)
void mock_file_free(struct drm_i915_private *i915, struct drm_file *file)
{
struct inode inode = fake_inode(i915);
- struct file filp = { .private_data = file };
+ struct file *filp = file->filp;

- drm_release(&inode, &filp);
+ drm_release(&inode, filp);
+
+ kfree(filp);
}
--
2.9.0
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