zram: add set_max_streams knob

[cascardo/linux.git] / drivers / block / zram / zcomp.c

diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index c06f75f..ac276f7 100644 (file)
--- a/drivers/block/zram/zcomp.c
+++ b/drivers/block/zram/zcomp.c
@@ -136,6 +136,29 @@ static void zcomp_strm_multi_release(struct zcomp *comp, struct zcomp_strm *zstr
        zcomp_strm_free(comp, zstrm);
 }
 
+/* change max_strm limit */
+static int zcomp_strm_multi_set_max_streams(struct zcomp *comp, int num_strm)
+{
+       struct zcomp_strm_multi *zs = comp->stream;
+       struct zcomp_strm *zstrm;
+
+       spin_lock(&zs->strm_lock);
+       zs->max_strm = num_strm;
+       /*
+        * if user has lowered the limit and there are idle streams,
+        * immediately free as much streams (and memory) as we can.
+        */
+       while (zs->avail_strm > num_strm && !list_empty(&zs->idle_strm)) {
+               zstrm = list_entry(zs->idle_strm.next,
+                               struct zcomp_strm, list);
+               list_del(&zstrm->list);
+               zcomp_strm_free(comp, zstrm);
+               zs->avail_strm--;
+       }
+       spin_unlock(&zs->strm_lock);
+       return 0;
+}
+
 static void zcomp_strm_multi_destroy(struct zcomp *comp)
 {
        struct zcomp_strm_multi *zs = comp->stream;
@@ -158,6 +181,7 @@ static int zcomp_strm_multi_create(struct zcomp *comp, int max_strm)
        comp->destroy = zcomp_strm_multi_destroy;
        comp->strm_find = zcomp_strm_multi_find;
        comp->strm_release = zcomp_strm_multi_release;
+       comp->set_max_streams = zcomp_strm_multi_set_max_streams;
        zs = kmalloc(sizeof(struct zcomp_strm_multi), GFP_KERNEL);
        if (!zs)
                return -ENOMEM;
@@ -192,6 +216,12 @@ 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)
+{
+       /* zcomp_strm_single support only max_comp_streams == 1 */
+       return -ENOTSUPP;
+}
+
 static void zcomp_strm_single_destroy(struct zcomp *comp)
 {
        struct zcomp_strm_single *zs = comp->stream;
@@ -206,6 +236,7 @@ static int zcomp_strm_single_create(struct zcomp *comp)
        comp->destroy = zcomp_strm_single_destroy;
        comp->strm_find = zcomp_strm_single_find;
        comp->strm_release = zcomp_strm_single_release;
+       comp->set_max_streams = zcomp_strm_single_set_max_streams;
        zs = kmalloc(sizeof(struct zcomp_strm_single), GFP_KERNEL);
        if (!zs)
                return -ENOMEM;
@@ -220,6 +251,11 @@ static int zcomp_strm_single_create(struct zcomp *comp)
        return 0;
 }
 
+int zcomp_set_max_streams(struct zcomp *comp, int num_strm)
+{
+       return comp->set_max_streams(comp, num_strm);
+}
+
 struct zcomp_strm *zcomp_strm_find(struct zcomp *comp)
 {
        return comp->strm_find(comp);