From 680753dd9d7d9e4a64515f41cc882471869963a6 Mon Sep 17 00:00:00 2001 From: Christian König Date: Thu, 6 May 2021 15:00:31 +0200 Subject: dma-buf: fix inconsistent debug print v2 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Drop the whole rcu handling since we are holding the resv lock anyway. v2: drop all rcu handling instead. Signed-off-by: Christian König Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210602140359.272601-1-christian.koenig@amd.com --- drivers/dma-buf/dma-buf.c | 27 +++++++++------------------ 1 file changed, 9 insertions(+), 18 deletions(-) (limited to 'drivers/dma-buf') diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index eadd1eaa2fb5..ee04fb442015 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -1349,15 +1349,14 @@ EXPORT_SYMBOL_GPL(dma_buf_vunmap); #ifdef CONFIG_DEBUG_FS static int dma_buf_debug_show(struct seq_file *s, void *unused) { - int ret; struct dma_buf *buf_obj; struct dma_buf_attachment *attach_obj; struct dma_resv *robj; struct dma_resv_list *fobj; struct dma_fence *fence; - unsigned seq; int count = 0, attach_count, shared_count, i; size_t size = 0; + int ret; ret = mutex_lock_interruptible(&db_list.lock); @@ -1383,33 +1382,25 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused) buf_obj->name ?: ""); robj = buf_obj->resv; - while (true) { - seq = read_seqcount_begin(&robj->seq); - rcu_read_lock(); - fobj = rcu_dereference(robj->fence); - shared_count = fobj ? fobj->shared_count : 0; - fence = rcu_dereference(robj->fence_excl); - if (!read_seqcount_retry(&robj->seq, seq)) - break; - rcu_read_unlock(); - } - + fence = rcu_dereference_protected(robj->fence_excl, + dma_resv_held(robj)); if (fence) seq_printf(s, "\tExclusive fence: %s %s %ssignalled\n", fence->ops->get_driver_name(fence), fence->ops->get_timeline_name(fence), dma_fence_is_signaled(fence) ? "" : "un"); + + fobj = rcu_dereference_protected(robj->fence, + dma_resv_held(robj)); + shared_count = fobj ? fobj->shared_count : 0; for (i = 0; i < shared_count; i++) { - fence = rcu_dereference(fobj->shared[i]); - if (!dma_fence_get_rcu(fence)) - continue; + fence = rcu_dereference_protected(fobj->shared[i], + dma_resv_held(robj)); seq_printf(s, "\tShared fence: %s %s %ssignalled\n", fence->ops->get_driver_name(fence), fence->ops->get_timeline_name(fence), dma_fence_is_signaled(fence) ? "" : "un"); - dma_fence_put(fence); } - rcu_read_unlock(); seq_puts(s, "\tAttached Devices:\n"); attach_count = 0; -- cgit v1.2.3-59-g8ed1b