On Wed, Jun 03, 2020 at 04:49:49PM +0200, Ahmed S. Darwish wrote:
Commit 3c3b177a9369 ("reservation: add support for read-only access using rcu") introduced a sequence counter to manage updates to reservations. Back then, the reservation object initializer reservation_object_init() was always inlined.
Having the sequence counter initialization inlined meant that each of the call sites would have a different lockdep class key, which would've broken lockdep's deadlock detection. The aforementioned commit thus introduced, and exported, a custom seqcount lockdep class key and name.
The commit 8735f16803f00 ("dma-buf: cleanup reservation_object_init...") transformed the reservation object initializer to a normal non-inlined C function. seqcount_init(), which automatically defines the seqcount lockdep class key and must be called non-inlined, can now be safely used.
Remove the seqcount custom lockdep class key, name, and export. Use seqcount_init() inside the dma reservation object initializer.
Signed-off-by: Ahmed S. Darwish a.darwish@linutronix.de Reviewed-by: Sebastian Andrzej Siewior bigeasy@linutronix.de
Patch lgtm, and Ahmed says plan is that this should land through -tip since it's part of a larger series, so
Acked-by: Daniel Vetter daniel.vetter@ffwll.ch
for merging through whatever tree/branch fits bets. I don't expect conflicts here, nothing in-flight touching this. I expect this will show up in 5.9-rc1 or so.
Cheers, Daniel
drivers/dma-buf/dma-resv.c | 9 +-------- include/linux/dma-resv.h | 2 -- 2 files changed, 1 insertion(+), 10 deletions(-)
diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index 4264e64788c4..590ce7ad60a0 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -50,12 +50,6 @@ DEFINE_WD_CLASS(reservation_ww_class); EXPORT_SYMBOL(reservation_ww_class);
-struct lock_class_key reservation_seqcount_class; -EXPORT_SYMBOL(reservation_seqcount_class);
-const char reservation_seqcount_string[] = "reservation_seqcount"; -EXPORT_SYMBOL(reservation_seqcount_string);
/**
- dma_resv_list_alloc - allocate fence list
- @shared_max: number of fences we need space for
@@ -134,9 +128,8 @@ subsys_initcall(dma_resv_lockdep); void dma_resv_init(struct dma_resv *obj) { ww_mutex_init(&obj->lock, &reservation_ww_class);
- seqcount_init(&obj->seq);
- __seqcount_init(&obj->seq, reservation_seqcount_string,
&reservation_seqcount_class);} diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h index ee50d10f052b..a6538ae7d93f 100644 --- a/include/linux/dma-resv.h +++ b/include/linux/dma-resv.h @@ -46,8 +46,6 @@ #include <linux/rcupdate.h>
extern struct ww_class reservation_ww_class; -extern struct lock_class_key reservation_seqcount_class; -extern const char reservation_seqcount_string[];
/**
- struct dma_resv_list - a list of shared fences
-- 2.20.1