From: Ahmed S. Darwish Date: Mon, 20 Jul 2020 15:55:17 +0000 (+0200) Subject: dma-buf: Remove custom seqcount lockdep class key X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=318ce71f3e3ae4108c1665f3860afa8a2a4c9f02;p=linux.git dma-buf: Remove custom seqcount lockdep class key 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 Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Sebastian Andrzej Siewior Acked-by: Daniel Vetter Link: https://lkml.kernel.org/r/20200720155530.1173732-12-a.darwish@linutronix.de --- diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c index b45f8514dc826..15efa0c2dacbe 100644 --- a/drivers/dma-buf/dma-resv.c +++ b/drivers/dma-buf/dma-resv.c @@ -51,12 +51,6 @@ 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 @@ -135,9 +129,8 @@ 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); RCU_INIT_POINTER(obj->fence, NULL); RCU_INIT_POINTER(obj->fence_excl, NULL); } diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h index ee50d10f052b5..a6538ae7d93f1 100644 --- a/include/linux/dma-resv.h +++ b/include/linux/dma-resv.h @@ -46,8 +46,6 @@ #include 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