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authorCorentin Labbe <clabbe@baylibre.com>2019-01-18 13:44:18 +0000
committerChristoph Hellwig <hch@lst.de>2019-02-01 10:06:44 +0100
commit0a3b192c26da198fce38e1ee242a34f558670246 (patch)
tree50c7205f8335fed7863f9446db981936cd350a6e
parentdma: debug: no need to check return value of debugfs_create functions (diff)
downloadlinux-dev-0a3b192c26da198fce38e1ee242a34f558670246.tar.xz
linux-dev-0a3b192c26da198fce38e1ee242a34f558670246.zip
dma-debug: add dumping facility via debugfs
While debugging a DMA mapping leak, I needed to access debug_dma_dump_mappings() but easily from user space. This patch adds a /sys/kernel/debug/dma-api/dump file which contain all current DMA mapping. Signed-off-by: Corentin Labbe <clabbe@baylibre.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to '')
-rw-r--r--Documentation/DMA-API.txt3
-rw-r--r--kernel/dma/debug.c28
2 files changed, 31 insertions, 0 deletions
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index e133ccd60228..78114ee63057 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -696,6 +696,9 @@ dma-api/disabled This read-only file contains the character 'Y'
happen when it runs out of memory or if it was
disabled at boot time
+dma-api/dump This read-only file contains current DMA
+ mappings.
+
dma-api/error_count This file is read-only and shows the total
numbers of errors found.
diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index 56cd836a902c..45d51e8e26f6 100644
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c
@@ -829,6 +829,33 @@ static const struct file_operations filter_fops = {
.llseek = default_llseek,
};
+static int dump_show(struct seq_file *seq, void *v)
+{
+ int idx;
+
+ for (idx = 0; idx < HASH_SIZE; idx++) {
+ struct hash_bucket *bucket = &dma_entry_hash[idx];
+ struct dma_debug_entry *entry;
+ unsigned long flags;
+
+ spin_lock_irqsave(&bucket->lock, flags);
+ list_for_each_entry(entry, &bucket->list, list) {
+ seq_printf(seq,
+ "%s %s %s idx %d P=%llx N=%lx D=%llx L=%llx %s %s\n",
+ dev_name(entry->dev),
+ dev_driver_string(entry->dev),
+ type2name[entry->type], idx,
+ phys_addr(entry), entry->pfn,
+ entry->dev_addr, entry->size,
+ dir2name[entry->direction],
+ maperr2str[entry->map_err_type]);
+ }
+ spin_unlock_irqrestore(&bucket->lock, flags);
+ }
+ return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(dump);
+
static void dma_debug_fs_init(void)
{
struct dentry *dentry = debugfs_create_dir("dma-api", NULL);
@@ -841,6 +868,7 @@ static void dma_debug_fs_init(void)
debugfs_create_u32("min_free_entries", 0444, dentry, &min_free_entries);
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);
}
static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)