dma-debug: fix debugfs initialization order

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>

diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index fe6efd1816146b17215a46835b016afd6f9d3808..6c90c69e5311afa9347b4f0df90412b544ed8280 100644 (file)
--- 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);