Hello, Dan:
2016-04-28 23:36 GMT+08:00 Dan Streetman <ddstreet@xxxxxxxx>:
> 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@xxxxxxxxxxxxx>
> Signed-off-by: Dan Streetman <ddstreet@xxxxxxxx>
> ---
> 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;
Since the error will not be propagated, Would it be better if you
add some pr_warn information here(also in zs_stat_init() if you
send your V2 patch as Minchan suggested)? It will be useful for
developers to know the reason of failed to create debugfs file/dir.
Thanks.
>
> 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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