zram: propagate error to user

When we initialized zcomp with single, we couldn't change
max_comp_streams without zram reset but current interface doesn't show
any error to user and even it changes max_comp_streams's value without
any effect so it would make user very confusing.

This patch prevents max_comp_streams's change when zcomp was initialized
as single zcomp and emit the error to user(ex, echo).

[akpm@linux-foundation.org: don't return with the lock held, per Sergey]
[fengguang.wu@intel.com: fix coccinelle warnings]
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 5 deletions

diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index 5647d8fe1dc1..b0e7592c44d8 100644
--- a/drivers/block/zram/zcomp.c
+++ b/drivers/block/zram/zcomp.c
@@ -153,7 +153,7 @@ static void zcomp_strm_multi_release(struct zcomp *comp, struct zcomp_strm *zstr
 }
 
 /* change max_strm limit */
-static int zcomp_strm_multi_set_max_streams(struct zcomp *comp, int num_strm)
+static bool zcomp_strm_multi_set_max_streams(struct zcomp *comp, int num_strm)
 {
         struct zcomp_strm_multi *zs = comp->stream;
         struct zcomp_strm *zstrm;
@@ -172,7 +172,7 @@ static int zcomp_strm_multi_set_max_streams(struct zcomp *comp, int num_strm)
                 zs->avail_strm--;
         }
         spin_unlock(&zs->strm_lock);
-        return 0;
+        return true;
 }
 
 static void zcomp_strm_multi_destroy(struct zcomp *comp)
@@ -232,10 +232,10 @@ static void zcomp_strm_single_release(struct zcomp *comp,
         mutex_unlock(&zs->strm_lock);
 }
 
-static int zcomp_strm_single_set_max_streams(struct zcomp *comp, int num_strm)
+static bool zcomp_strm_single_set_max_streams(struct zcomp *comp, int num_strm)
 {
         /* zcomp_strm_single support only max_comp_streams == 1 */
-        return -ENOTSUPP;
+        return false;
 }
 
 static void zcomp_strm_single_destroy(struct zcomp *comp)
@@ -284,7 +284,7 @@ ssize_t zcomp_available_show(const char *comp, char *buf)
         return sz;
 }
 
-int zcomp_set_max_streams(struct zcomp *comp, int num_strm)
+bool zcomp_set_max_streams(struct zcomp *comp, int num_strm)
 {
         return comp->set_max_streams(comp, num_strm);
 }