[PATCH 5.14 102/432] dma-debug: fix debugfs initialization order

Greg Kroah-Hartman
2021-09-16T17:19:33Z

From: Anthony Iliopoulos <ailiop@suse.com>

[ Upstream commit 173735c346c412d9f084825ecb04f24ada0e2986 ]

Due to link order, dma_debug_init is called before debugfs has a chance
to initialize (via debugfs_init which also happens in the core initcall
stage), so the directories for dma-debug are never created.

Decouple dma_debug_fs_init from dma_debug_init and defer its init until
core_initcall_sync (after debugfs has been initialized) while letting
dma-debug initialization occur as soon as possible to catch any early
mappings, as suggested in [1].

[1] https://lore.kernel.org/linux-iommu/YIgGa6yF%2Fadg8OSN@kroah.com/

Fixes: 15b28bbcd567 ("dma-debug: move initialization to common code")
Signed-off-by: Anthony Iliopoulos <ailiop@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/dma/debug.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index dadae6255d05..f2faa13534e5 100644
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c
@@ -792,7 +792,7 @@ static int dump_show(struct seq_file *seq, void *v)
}
DEFINE_SHOW_ATTRIBUTE(dump);

-static void dma_debug_fs_init(void)
+static int __init dma_debug_fs_init(void)
{
struct dentry *dentry = debugfs_create_dir("dma-api", NULL);

@@ -805,7 +805,10 @@ static void dma_debug_fs_init(void)
debugfs_create_u32("nr_total_entries", 0444, dentry, &nr_total_entries);
debugfs_create_file("driver_filter", 0644, dentry, NULL, &filter_fops);
debugfs_create_file("dump", 0444, dentry, NULL, &dump_fops);
+
+ return 0;
}
+core_initcall_sync(dma_debug_fs_init);

static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
{
@@ -890,8 +893,6 @@ static int dma_debug_init(void)
spin_lock_init(&dma_entry_hash[i].lock);
}

- dma_debug_fs_init();
-
nr_pages = DIV_ROUND_UP(nr_prealloc_entries, DMA_DEBUG_DYNAMIC_ENTRIES);
for (i = 0; i < nr_pages; ++i)
dma_debug_create_entries(GFP_KERNEL);
--
2.30.2