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* [PATCH] mm/zsmalloc: don't fail if can't create debugfs info
@ 2016-04-28 15:36 Dan Streetman
  2016-04-28 22:07 ` Andrew Morton
  2016-05-03  2:18 ` Ganesh Mahendran
  0 siblings, 2 replies; 12+ messages in thread
From: Dan Streetman @ 2016-04-28 15:36 UTC (permalink / raw)
  To: Minchan Kim, Nitin Gupta, Andrew Morton
  Cc: Sergey Senozhatsky, Seth Jennings, Yu Zhao, Linux-MM,
	Sergey Senozhatsky, linux-kernel, Dan Streetman, Dan Streetman

Change the return type of zs_pool_stat_create() to void, and
remove the logic to abort pool creation if the stat debugfs
dir/file could not be created.

The debugfs stat file is for debugging/information only, and doesn't
affect operation of zsmalloc; there is no reason to abort creating
the pool if the stat file can't be created.  This was seen with
zswap, which used the same name for all pool creations, which caused
zsmalloc to fail to create a second pool for zswap if
CONFIG_ZSMALLOC_STAT was enabled.

Cc: Dan Streetman <dan.streetman@canonical.com>
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
---
 mm/zsmalloc.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index e72efb1..25a7db2 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -567,17 +567,17 @@ static const struct file_operations zs_stat_size_ops = {
 	.release        = single_release,
 };
 
-static int zs_pool_stat_create(const char *name, struct zs_pool *pool)
+static void zs_pool_stat_create(const char *name, struct zs_pool *pool)
 {
 	struct dentry *entry;
 
 	if (!zs_stat_root)
-		return -ENODEV;
+		return;
 
 	entry = debugfs_create_dir(name, zs_stat_root);
 	if (!entry) {
 		pr_warn("debugfs dir <%s> creation failed\n", name);
-		return -ENOMEM;
+		return;
 	}
 	pool->stat_dentry = entry;
 
@@ -586,10 +586,8 @@ static int zs_pool_stat_create(const char *name, struct zs_pool *pool)
 	if (!entry) {
 		pr_warn("%s: debugfs file entry <%s> creation failed\n",
 				name, "classes");
-		return -ENOMEM;
+		return;
 	}
-
-	return 0;
 }
 
 static void zs_pool_stat_destroy(struct zs_pool *pool)
@@ -607,9 +605,8 @@ static void __exit zs_stat_exit(void)
 {
 }
 
-static inline int zs_pool_stat_create(const char *name, struct zs_pool *pool)
+static inline void zs_pool_stat_create(const char *name, struct zs_pool *pool)
 {
-	return 0;
 }
 
 static inline void zs_pool_stat_destroy(struct zs_pool *pool)
@@ -1956,8 +1953,8 @@ struct zs_pool *zs_create_pool(const char *name, gfp_t flags)
 
 	pool->flags = flags;
 
-	if (zs_pool_stat_create(name, pool))
-		goto err;
+	/* debug only, don't abort if it fails */
+	zs_pool_stat_create(name, pool);
 
 	/*
 	 * Not critical, we still can use the pool
-- 
2.7.4

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^ permalink raw reply	[flat|nested] 12+ messages in thread

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Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-04-28 15:36 [PATCH] mm/zsmalloc: don't fail if can't create debugfs info Dan Streetman
2016-04-28 22:07 ` Andrew Morton
2016-04-29  0:38   ` Sergey Senozhatsky
2016-04-29  5:37     ` Minchan Kim
2016-04-29 14:50       ` Dan Streetman
2016-04-29 15:33         ` Minchan Kim
2016-05-03  2:18 ` Ganesh Mahendran
2016-05-19 15:18   ` [PATCHv2] " Dan Streetman
2016-05-20  2:33     ` Ganesh Mahendran
2016-05-20  4:08     ` Sergey Senozhatsky
2016-05-20 10:32       ` Dan Streetman
2016-05-23  3:03     ` Minchan Kim

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