linux-kernel - [PATCH] dma: debug: no need to check return value of debugfs

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Date:   Tue, 22 Jan 2019 16:21:38 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Christoph Hellwig <hch@....de>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Robin Murphy <robin.murphy@....com>,
        iommu@...ts.linux-foundation.org
Subject: [PATCH] dma: debug: no need to check return value of debugfs_create functions

When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Also delete the variables for the file dentries for the debugfs entries
as they are never used at all once they are created.

Cc: Christoph Hellwig <hch@....de>
Cc: Marek Szyprowski <m.szyprowski@...sung.com>
Cc: Robin Murphy <robin.murphy@....com>
Cc: iommu@...ts.linux-foundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 kernel/dma/debug.c | 81 ++++++----------------------------------------
 1 file changed, 10 insertions(+), 71 deletions(-)

diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index 23cf5361bcf1..2f5fc8b9d39f 100644
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c
@@ -136,14 +136,6 @@ static u32 nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
 
 /* debugfs dentry's for the stuff above */
 static struct dentry *dma_debug_dent        __read_mostly;
-static struct dentry *global_disable_dent   __read_mostly;
-static struct dentry *error_count_dent      __read_mostly;
-static struct dentry *show_all_errors_dent  __read_mostly;
-static struct dentry *show_num_errors_dent  __read_mostly;
-static struct dentry *num_free_entries_dent __read_mostly;
-static struct dentry *min_free_entries_dent __read_mostly;
-static struct dentry *nr_total_entries_dent __read_mostly;
-static struct dentry *filter_dent           __read_mostly;
 
 /* per-driver filter related state */
 
@@ -840,66 +832,18 @@ static const struct file_operations filter_fops = {
 	.llseek = default_llseek,
 };
 
-static int dma_debug_fs_init(void)
+static void dma_debug_fs_init(void)
 {
 	dma_debug_dent = debugfs_create_dir("dma-api", NULL);
-	if (!dma_debug_dent) {
-		pr_err("can not create debugfs directory\n");
-		return -ENOMEM;
-	}
-
-	global_disable_dent = debugfs_create_bool("disabled", 0444,
-			dma_debug_dent,
-			&global_disable);
-	if (!global_disable_dent)
-		goto out_err;
-
-	error_count_dent = debugfs_create_u32("error_count", 0444,
-			dma_debug_dent, &error_count);
-	if (!error_count_dent)
-		goto out_err;
-
-	show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
-			dma_debug_dent,
-			&show_all_errors);
-	if (!show_all_errors_dent)
-		goto out_err;
-
-	show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
-			dma_debug_dent,
-			&show_num_errors);
-	if (!show_num_errors_dent)
-		goto out_err;
-
-	num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
-			dma_debug_dent,
-			&num_free_entries);
-	if (!num_free_entries_dent)
-		goto out_err;
-
-	min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
-			dma_debug_dent,
-			&min_free_entries);
-	if (!min_free_entries_dent)
-		goto out_err;
-
-	nr_total_entries_dent = debugfs_create_u32("nr_total_entries", 0444,
-			dma_debug_dent,
-			&nr_total_entries);
-	if (!nr_total_entries_dent)
-		goto out_err;
-
-	filter_dent = debugfs_create_file("driver_filter", 0644,
-					  dma_debug_dent, NULL, &filter_fops);
-	if (!filter_dent)
-		goto out_err;
-
-	return 0;
 
-out_err:
-	debugfs_remove_recursive(dma_debug_dent);
-
-	return -ENOMEM;
+	debugfs_create_bool("disabled", 0444, dma_debug_dent, &global_disable);
+	debugfs_create_u32("error_count", 0444, dma_debug_dent, &error_count);
+	debugfs_create_u32("all_errors", 0644, dma_debug_dent, &show_all_errors);
+	debugfs_create_u32("num_errors", 0644, dma_debug_dent, &show_num_errors);
+	debugfs_create_u32("num_free_entries", 0444, dma_debug_dent, &num_free_entries);
+	debugfs_create_u32("min_free_entries", 0444, dma_debug_dent, &min_free_entries);
+	debugfs_create_u32("nr_total_entries", 0444, dma_debug_dent, &nr_total_entries);
+	debugfs_create_file("driver_filter", 0644, dma_debug_dent, NULL, &filter_fops);
 }
 
 static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
@@ -985,12 +929,7 @@ static int dma_debug_init(void)
 		spin_lock_init(&dma_entry_hash[i].lock);
 	}
 
-	if (dma_debug_fs_init() != 0) {
-		pr_err("error creating debugfs entries - disabling\n");
-		global_disable = true;
-
-		return 0;
-	}
+	dma_debug_fs_init();
 
 	nr_pages = DIV_ROUND_UP(nr_prealloc_entries, DMA_DEBUG_DYNAMIC_ENTRIES);
 	for (i = 0; i < nr_pages; ++i)
-- 
2.20.1