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c21f11d182
In mutex_init() lockdep identifies a lock by defining a special static
key for each lock class. However if we wrap the macro in a function,
like in drmm_mutex_init(), we end up generating:
int drmm_mutex_init(struct drm_device *dev, struct mutex *lock)
{
static struct lock_class_key __key;
__mutex_init((lock), "lock", &__key);
....
}
The static __key here is what lockdep uses to identify the lock class,
however since this is just a normal function the key here will be
created once, where all callers then use the same key. In effect the
mutex->depmap.key will be the same pointer for different
drmm_mutex_init() callers. This then results in impossible lockdep
splats since lockdep thinks completely unrelated locks are the same lock
class.
To fix this turn drmm_mutex_init() into a macro such that it generates a
different "static struct lock_class_key __key" for each invocation,
which looks to be inline with what mutex_init() wants.
v2:
- Revamp the commit message with clearer explanation of the issue.
- Rather export __drmm_mutex_release() than static inline.
Reported-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reported-by: Sarah Walker <sarah.walker@imgtec.com>
Fixes: e13f13e039 ("drm: Add DRM-managed mutex_init()")
Cc: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Cc: Boris Brezillon <boris.brezillon@collabora.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Jocelyn Falempe <jfalempe@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230519090733.489019-1-matthew.auld@intel.com
127 lines
3.9 KiB
C
127 lines
3.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#ifndef _DRM_MANAGED_H_
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#define _DRM_MANAGED_H_
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#include <linux/gfp.h>
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#include <linux/overflow.h>
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#include <linux/types.h>
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struct drm_device;
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struct mutex;
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typedef void (*drmres_release_t)(struct drm_device *dev, void *res);
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/**
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* drmm_add_action - add a managed release action to a &drm_device
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* @dev: DRM device
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* @action: function which should be called when @dev is released
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* @data: opaque pointer, passed to @action
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*
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* This function adds the @release action with optional parameter @data to the
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* list of cleanup actions for @dev. The cleanup actions will be run in reverse
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* order in the final drm_dev_put() call for @dev.
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*/
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#define drmm_add_action(dev, action, data) \
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__drmm_add_action(dev, action, data, #action)
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int __must_check __drmm_add_action(struct drm_device *dev,
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drmres_release_t action,
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void *data, const char *name);
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/**
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* drmm_add_action_or_reset - add a managed release action to a &drm_device
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* @dev: DRM device
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* @action: function which should be called when @dev is released
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* @data: opaque pointer, passed to @action
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*
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* Similar to drmm_add_action(), with the only difference that upon failure
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* @action is directly called for any cleanup work necessary on failures.
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*/
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#define drmm_add_action_or_reset(dev, action, data) \
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__drmm_add_action_or_reset(dev, action, data, #action)
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int __must_check __drmm_add_action_or_reset(struct drm_device *dev,
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drmres_release_t action,
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void *data, const char *name);
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void *drmm_kmalloc(struct drm_device *dev, size_t size, gfp_t gfp) __malloc;
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/**
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* drmm_kzalloc - &drm_device managed kzalloc()
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* @dev: DRM device
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* @size: size of the memory allocation
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* @gfp: GFP allocation flags
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*
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* This is a &drm_device managed version of kzalloc(). The allocated memory is
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* automatically freed on the final drm_dev_put(). Memory can also be freed
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* before the final drm_dev_put() by calling drmm_kfree().
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*/
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static inline void *drmm_kzalloc(struct drm_device *dev, size_t size, gfp_t gfp)
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{
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return drmm_kmalloc(dev, size, gfp | __GFP_ZERO);
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}
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/**
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* drmm_kmalloc_array - &drm_device managed kmalloc_array()
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* @dev: DRM device
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* @n: number of array elements to allocate
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* @size: size of array member
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* @flags: GFP allocation flags
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*
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* This is a &drm_device managed version of kmalloc_array(). The allocated
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* memory is automatically freed on the final drm_dev_put() and works exactly
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* like a memory allocation obtained by drmm_kmalloc().
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*/
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static inline void *drmm_kmalloc_array(struct drm_device *dev,
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size_t n, size_t size, gfp_t flags)
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{
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size_t bytes;
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if (unlikely(check_mul_overflow(n, size, &bytes)))
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return NULL;
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return drmm_kmalloc(dev, bytes, flags);
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}
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/**
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* drmm_kcalloc - &drm_device managed kcalloc()
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* @dev: DRM device
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* @n: number of array elements to allocate
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* @size: size of array member
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* @flags: GFP allocation flags
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*
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* This is a &drm_device managed version of kcalloc(). The allocated memory is
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* automatically freed on the final drm_dev_put() and works exactly like a
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* memory allocation obtained by drmm_kmalloc().
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*/
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static inline void *drmm_kcalloc(struct drm_device *dev,
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size_t n, size_t size, gfp_t flags)
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{
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return drmm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
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}
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char *drmm_kstrdup(struct drm_device *dev, const char *s, gfp_t gfp);
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void drmm_kfree(struct drm_device *dev, void *data);
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void __drmm_mutex_release(struct drm_device *dev, void *res);
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/**
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* drmm_mutex_init - &drm_device-managed mutex_init()
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* @dev: DRM device
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* @lock: lock to be initialized
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*
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* Returns:
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* 0 on success, or a negative errno code otherwise.
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*
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* This is a &drm_device-managed version of mutex_init(). The initialized
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* lock is automatically destroyed on the final drm_dev_put().
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*/
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#define drmm_mutex_init(dev, lock) ({ \
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mutex_init(lock); \
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drmm_add_action_or_reset(dev, __drmm_mutex_release, lock); \
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}) \
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#endif
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