This adds lockdep asserts to the reservation functions which state in their documentation that obj->lock must be held. Allows builds with PROVE_LOCKING enabled to check that the locking requirements are met.
Signed-off-by: Lucas Stach l.stach@pengutronix.de --- drivers/dma-buf/reservation.c | 8 ++++++++ include/linux/reservation.h | 2 ++ 2 files changed, 10 insertions(+)
diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c index b44d9d7db347..accd398e2ea6 100644 --- a/drivers/dma-buf/reservation.c +++ b/drivers/dma-buf/reservation.c @@ -71,6 +71,8 @@ int reservation_object_reserve_shared(struct reservation_object *obj) struct reservation_object_list *fobj, *old; u32 max;
+ reservation_object_assert_held(obj); + old = reservation_object_get_list(obj);
if (old && old->shared_max) { @@ -211,6 +213,8 @@ void reservation_object_add_shared_fence(struct reservation_object *obj, { struct reservation_object_list *old, *fobj = obj->staged;
+ reservation_object_assert_held(obj); + old = reservation_object_get_list(obj); obj->staged = NULL;
@@ -236,6 +240,8 @@ void reservation_object_add_excl_fence(struct reservation_object *obj, struct reservation_object_list *old; u32 i = 0;
+ reservation_object_assert_held(obj); + old = reservation_object_get_list(obj); if (old) i = old->shared_count; @@ -276,6 +282,8 @@ int reservation_object_copy_fences(struct reservation_object *dst, size_t size; unsigned i;
+ reservation_object_assert_held(dst); + rcu_read_lock(); src_list = rcu_dereference(src->fence);
diff --git a/include/linux/reservation.h b/include/linux/reservation.h index 21fc84d82d41..55e7318800fd 100644 --- a/include/linux/reservation.h +++ b/include/linux/reservation.h @@ -212,6 +212,8 @@ reservation_object_unlock(struct reservation_object *obj) static inline struct dma_fence * reservation_object_get_excl(struct reservation_object *obj) { + reservation_object_assert_held(obj); + return rcu_dereference_protected(obj->fence_excl, reservation_object_held(obj)); }
Did this fall through the cracks over the holidays? It really has made my work much easier while reworking some of the reservation object handling in etnaviv and I think it might benefit others.
Regards, Lucas
Am Freitag, den 01.12.2017, 12:12 +0100 schrieb Lucas Stach:
This adds lockdep asserts to the reservation functions which state in their documentation that obj->lock must be held. Allows builds with PROVE_LOCKING enabled to check that the locking requirements are met.
Signed-off-by: Lucas Stach l.stach@pengutronix.de
drivers/dma-buf/reservation.c | 8 ++++++++ include/linux/reservation.h | 2 ++ 2 files changed, 10 insertions(+)
diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c index b44d9d7db347..accd398e2ea6 100644 --- a/drivers/dma-buf/reservation.c +++ b/drivers/dma-buf/reservation.c @@ -71,6 +71,8 @@ int reservation_object_reserve_shared(struct reservation_object *obj)
struct reservation_object_list *fobj, *old; u32 max;
- reservation_object_assert_held(obj);
old = reservation_object_get_list(obj);
if (old && old->shared_max) {
@@ -211,6 +213,8 @@ void reservation_object_add_shared_fence(struct reservation_object *obj, {
struct reservation_object_list *old, *fobj = obj->staged;
- reservation_object_assert_held(obj);
old = reservation_object_get_list(obj); obj->staged = NULL;
@@ -236,6 +240,8 @@ void reservation_object_add_excl_fence(struct reservation_object *obj,
struct reservation_object_list *old; u32 i = 0;
- reservation_object_assert_held(obj);
old = reservation_object_get_list(obj); if (old) i = old->shared_count;
@@ -276,6 +282,8 @@ int reservation_object_copy_fences(struct reservation_object *dst,
size_t size; unsigned i;
- reservation_object_assert_held(dst);
rcu_read_lock(); src_list = rcu_dereference(src->fence);
diff --git a/include/linux/reservation.h b/include/linux/reservation.h index 21fc84d82d41..55e7318800fd 100644 --- a/include/linux/reservation.h +++ b/include/linux/reservation.h @@ -212,6 +212,8 @@ reservation_object_unlock(struct reservation_object *obj) static inline struct dma_fence * reservation_object_get_excl(struct reservation_object *obj) {
- reservation_object_assert_held(obj);
return rcu_dereference_protected(obj->fence_excl, reservation_object_held(obj));
}
Yeah, somehow missed that one.
The patch looks mostly good, except for reservation_object_get_excl().
For that one an RCU protection is usually sufficient, so annotating it with reservation_object_assert_held() sounds incorrect to me.
Regards, Christian.
Am 11.01.2018 um 11:43 schrieb Lucas Stach:
Did this fall through the cracks over the holidays? It really has made my work much easier while reworking some of the reservation object handling in etnaviv and I think it might benefit others.
Regards, Lucas
Am Freitag, den 01.12.2017, 12:12 +0100 schrieb Lucas Stach:
This adds lockdep asserts to the reservation functions which state in their documentation that obj->lock must be held. Allows builds with PROVE_LOCKING enabled to check that the locking requirements are met.
Signed-off-by: Lucas Stach l.stach@pengutronix.de
drivers/dma-buf/reservation.c | 8 ++++++++ include/linux/reservation.h | 2 ++ 2 files changed, 10 insertions(+)
diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c index b44d9d7db347..accd398e2ea6 100644 --- a/drivers/dma-buf/reservation.c +++ b/drivers/dma-buf/reservation.c @@ -71,6 +71,8 @@ int reservation_object_reserve_shared(struct reservation_object *obj)
struct reservation_object_list *fobj, *old; u32 max;
- reservation_object_assert_held(obj);
old = reservation_object_get_list(obj);
if (old && old->shared_max) {
@@ -211,6 +213,8 @@ void reservation_object_add_shared_fence(struct reservation_object *obj, {
struct reservation_object_list *old, *fobj = obj->staged;
- reservation_object_assert_held(obj);
old = reservation_object_get_list(obj); obj->staged = NULL;
@@ -236,6 +240,8 @@ void reservation_object_add_excl_fence(struct reservation_object *obj,
struct reservation_object_list *old; u32 i = 0;
- reservation_object_assert_held(obj);
old = reservation_object_get_list(obj); if (old) i = old->shared_count;
@@ -276,6 +282,8 @@ int reservation_object_copy_fences(struct reservation_object *dst,
size_t size; unsigned i;
- reservation_object_assert_held(dst);
rcu_read_lock(); src_list = rcu_dereference(src->fence);
diff --git a/include/linux/reservation.h b/include/linux/reservation.h index 21fc84d82d41..55e7318800fd 100644 --- a/include/linux/reservation.h +++ b/include/linux/reservation.h @@ -212,6 +212,8 @@ reservation_object_unlock(struct reservation_object *obj) static inline struct dma_fence * reservation_object_get_excl(struct reservation_object *obj) {
- reservation_object_assert_held(obj);
return rcu_dereference_protected(obj->fence_excl, reservation_object_held(obj));
}
dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
Am Donnerstag, den 11.01.2018, 11:54 +0100 schrieb Christian König:
Yeah, somehow missed that one.
The patch looks mostly good, except for reservation_object_get_excl().
For that one an RCU protection is usually sufficient, so annotating it with reservation_object_assert_held() sounds incorrect to me.
Ah, you are correct. I was confused about this one as reservation_object_get_excl_rcu() exists and and the doc above reservation_object_get_excl() states "The obj->lock must be held.", which is misleading for the read-only case.
I'll send a v2 with that fixed.
Regards, Lucas
Regards, Christian.
Am 11.01.2018 um 11:43 schrieb Lucas Stach:
Did this fall through the cracks over the holidays? It really has made my work much easier while reworking some of the reservation object handling in etnaviv and I think it might benefit others.
Regards, Lucas
Am Freitag, den 01.12.2017, 12:12 +0100 schrieb Lucas Stach:
This adds lockdep asserts to the reservation functions which state in their documentation that obj->lock must be held. Allows builds with PROVE_LOCKING enabled to check that the locking requirements are met.
Signed-off-by: Lucas Stach l.stach@pengutronix.de
drivers/dma-buf/reservation.c | 8 ++++++++ include/linux/reservation.h | 2 ++ 2 files changed, 10 insertions(+)
diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c index b44d9d7db347..accd398e2ea6 100644 --- a/drivers/dma-buf/reservation.c +++ b/drivers/dma-buf/reservation.c @@ -71,6 +71,8 @@ int reservation_object_reserve_shared(struct reservation_object *obj)
> > struct reservation_object_list *fobj, *old;
u32 max;
- reservation_object_assert_held(obj);
old = reservation_object_get_list(obj);
if (old && old->shared_max) {
@@ -211,6 +213,8 @@ void reservation_object_add_shared_fence(struct reservation_object *obj, {
struct reservation_object_list *old, *fobj = obj->staged;
- reservation_object_assert_held(obj);
> > old = reservation_object_get_list(obj);
obj->staged = NULL;
@@ -236,6 +240,8 @@ void reservation_object_add_excl_fence(struct reservation_object *obj,
> > struct reservation_object_list *old;
u32 i = 0;
- reservation_object_assert_held(obj);
> > old = reservation_object_get_list(obj); > > if (old)
i = old->shared_count;
@@ -276,6 +282,8 @@ int reservation_object_copy_fences(struct reservation_object *dst,
> > size_t size;
unsigned i;
- reservation_object_assert_held(dst);
> > rcu_read_lock();
src_list = rcu_dereference(src->fence);
diff --git a/include/linux/reservation.h b/include/linux/reservation.h index 21fc84d82d41..55e7318800fd 100644 --- a/include/linux/reservation.h +++ b/include/linux/reservation.h @@ -212,6 +212,8 @@ reservation_object_unlock(struct reservation_object *obj) static inline struct dma_fence * reservation_object_get_excl(struct reservation_object *obj) {
- reservation_object_assert_held(obj);
> > return rcu_dereference_protected(obj->fence_excl,
reservation_object_held(obj));
}
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Christian König -
Lucas Stach