zram: zram memory size limitation

[firefly-linux-kernel-4.4.55.git] / drivers / block / zram / zram_drv.c

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index d0717743e2df54aaadf34cb5d99a80d995a7e0d8..3f4da06c89c08b9bd5fbc48efc9f838c6c66a0db 100644 (file)
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -122,6 +122,37 @@ static ssize_t max_comp_streams_show(struct device *dev,
        return scnprintf(buf, PAGE_SIZE, "%d\n", val);
 }
 
+static ssize_t mem_limit_show(struct device *dev,
+               struct device_attribute *attr, char *buf)
+{
+       u64 val;
+       struct zram *zram = dev_to_zram(dev);
+
+       down_read(&zram->init_lock);
+       val = zram->limit_pages;
+       up_read(&zram->init_lock);
+
+       return scnprintf(buf, PAGE_SIZE, "%llu\n", val << PAGE_SHIFT);
+}
+
+static ssize_t mem_limit_store(struct device *dev,
+               struct device_attribute *attr, const char *buf, size_t len)
+{
+       u64 limit;
+       char *tmp;
+       struct zram *zram = dev_to_zram(dev);
+
+       limit = memparse(buf, &tmp);
+       if (buf == tmp) /* no chars parsed, invalid input */
+               return -EINVAL;
+
+       down_write(&zram->init_lock);
+       zram->limit_pages = PAGE_ALIGN(limit) >> PAGE_SHIFT;
+       up_write(&zram->init_lock);
+
+       return len;
+}
+
 static ssize_t max_comp_streams_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t len)
 {
@@ -512,6 +543,14 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
                ret = -ENOMEM;
                goto out;
        }
+
+       if (zram->limit_pages &&
+               zs_get_total_pages(meta->mem_pool) > zram->limit_pages) {
+               zs_free(meta->mem_pool, handle);
+               ret = -ENOMEM;
+               goto out;
+       }
+
        cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_WO);
 
        if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) {
@@ -616,6 +655,9 @@ static void zram_reset_device(struct zram *zram, bool reset_capacity)
        struct zram_meta *meta;
 
        down_write(&zram->init_lock);
+
+       zram->limit_pages = 0;
+
        if (!init_done(zram)) {
                up_write(&zram->init_lock);
                return;
@@ -855,6 +897,8 @@ static DEVICE_ATTR(initstate, S_IRUGO, initstate_show, NULL);
 static DEVICE_ATTR(reset, S_IWUSR, NULL, reset_store);
 static DEVICE_ATTR(orig_data_size, S_IRUGO, orig_data_size_show, NULL);
 static DEVICE_ATTR(mem_used_total, S_IRUGO, mem_used_total_show, NULL);
+static DEVICE_ATTR(mem_limit, S_IRUGO | S_IWUSR, mem_limit_show,
+               mem_limit_store);
 static DEVICE_ATTR(max_comp_streams, S_IRUGO | S_IWUSR,
                max_comp_streams_show, max_comp_streams_store);
 static DEVICE_ATTR(comp_algorithm, S_IRUGO | S_IWUSR,
@@ -883,6 +927,7 @@ static struct attribute *zram_disk_attrs[] = {
        &dev_attr_orig_data_size.attr,
        &dev_attr_compr_data_size.attr,
        &dev_attr_mem_used_total.attr,
+       &dev_attr_mem_limit.attr,
        &dev_attr_max_comp_streams.attr,
        &dev_attr_comp_algorithm.attr,
        NULL,