From c21f11d182c2180d8b90eaff84f574cfa845b250 Mon Sep 17 00:00:00 2001 From: Matthew Auld Date: Fri, 19 May 2023 10:07:33 +0100 Subject: drm: fix drmm_mutex_init() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reported-by: Sarah Walker Fixes: e13f13e039dc ("drm: Add DRM-managed mutex_init()") Cc: Stanislaw Gruszka Cc: Boris Brezillon Cc: Thomas Zimmermann Cc: Jocelyn Falempe Cc: Daniel Vetter Cc: dri-devel@lists.freedesktop.org Signed-off-by: Matthew Auld Reviewed-by: Boris Brezillon Reviewed-by: Stanislaw Gruszka Reviewed-by: Lucas De Marchi Acked-by: Thomas Zimmermann Signed-off-by: Thomas Zimmermann Link: https://patchwork.freedesktop.org/patch/msgid/20230519090733.489019-1-matthew.auld@intel.com --- drivers/gpu/drm/drm_managed.c | 22 ++-------------------- 1 file changed, 2 insertions(+), 20 deletions(-) (limited to 'drivers/gpu/drm/drm_managed.c') diff --git a/drivers/gpu/drm/drm_managed.c b/drivers/gpu/drm/drm_managed.c index 4cf214de50c4..c21c3f623033 100644 --- a/drivers/gpu/drm/drm_managed.c +++ b/drivers/gpu/drm/drm_managed.c @@ -264,28 +264,10 @@ void drmm_kfree(struct drm_device *dev, void *data) } EXPORT_SYMBOL(drmm_kfree); -static void drmm_mutex_release(struct drm_device *dev, void *res) +void __drmm_mutex_release(struct drm_device *dev, void *res) { struct mutex *lock = res; mutex_destroy(lock); } - -/** - * drmm_mutex_init - &drm_device-managed mutex_init() - * @dev: DRM device - * @lock: lock to be initialized - * - * Returns: - * 0 on success, or a negative errno code otherwise. - * - * This is a &drm_device-managed version of mutex_init(). The initialized - * lock is automatically destroyed on the final drm_dev_put(). - */ -int drmm_mutex_init(struct drm_device *dev, struct mutex *lock) -{ - mutex_init(lock); - - return drmm_add_action_or_reset(dev, drmm_mutex_release, lock); -} -EXPORT_SYMBOL(drmm_mutex_init); +EXPORT_SYMBOL(__drmm_mutex_release); -- cgit v1.2.3 From 6716ccaf43e0fe2e759b84eb1cef4c684873a847 Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Mon, 12 Jun 2023 16:31:50 +0100 Subject: drivers/gpu: use ARCH_DMA_MINALIGN instead of ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN represents the minimum (static) alignment for safe DMA operations while ARCH_KMALLOC_MINALIGN is the minimum kmalloc() objects alignment. Link: https://lkml.kernel.org/r/20230612153201.554742-7-catalin.marinas@arm.com Signed-off-by: Catalin Marinas Tested-by: Isaac J. Manjarres Cc: Daniel Vetter Cc: Alasdair Kergon Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Christoph Hellwig Cc: Greg Kroah-Hartman Cc: Herbert Xu Cc: Jerry Snitselaar Cc: Joerg Roedel Cc: Jonathan Cameron Cc: Jonathan Cameron Cc: Lars-Peter Clausen Cc: Logan Gunthorpe Cc: Marc Zyngier Cc: Mark Brown Cc: Mike Snitzer Cc: "Rafael J. Wysocki" Cc: Robin Murphy Cc: Saravana Kannan Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton --- drivers/gpu/drm/drm_managed.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/gpu/drm/drm_managed.c') diff --git a/drivers/gpu/drm/drm_managed.c b/drivers/gpu/drm/drm_managed.c index c21c3f623033..5423ad883729 100644 --- a/drivers/gpu/drm/drm_managed.c +++ b/drivers/gpu/drm/drm_managed.c @@ -49,10 +49,10 @@ struct drmres { * Some archs want to perform DMA into kmalloc caches * and need a guaranteed alignment larger than * the alignment of a 64-bit integer. - * Thus we use ARCH_KMALLOC_MINALIGN here and get exactly the same - * buffer alignment as if it was allocated by plain kmalloc(). + * Thus we use ARCH_DMA_MINALIGN for data[] which will force the same + * alignment for struct drmres when allocated by kmalloc(). */ - u8 __aligned(ARCH_KMALLOC_MINALIGN) data[]; + u8 __aligned(ARCH_DMA_MINALIGN) data[]; }; static void free_dr(struct drmres *dr) -- cgit v1.2.3