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path: root/drivers/block/zram/zram_drv.c
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Diffstat (limited to 'drivers/block/zram/zram_drv.c')
-rw-r--r--drivers/block/zram/zram_drv.c48
1 files changed, 47 insertions, 1 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 81eb81f17ef9..fcdbbb1e7745 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -292,6 +292,9 @@ static void reset_bdev(struct zram *zram)
zram->backing_dev = NULL;
zram->old_block_size = 0;
zram->bdev = NULL;
+
+ kvfree(zram->bitmap);
+ zram->bitmap = NULL;
}
static ssize_t backing_dev_show(struct device *dev,
@@ -330,7 +333,8 @@ static ssize_t backing_dev_store(struct device *dev,
struct file *backing_dev = NULL;
struct inode *inode;
struct address_space *mapping;
- unsigned int old_block_size = 0;
+ unsigned int bitmap_sz, old_block_size = 0;
+ unsigned long nr_pages, *bitmap = NULL;
struct block_device *bdev = NULL;
int err;
struct zram *zram = dev_to_zram(dev);
@@ -369,16 +373,27 @@ static ssize_t backing_dev_store(struct device *dev,
if (err < 0)
goto out;
+ nr_pages = i_size_read(inode) >> PAGE_SHIFT;
+ bitmap_sz = BITS_TO_LONGS(nr_pages) * sizeof(long);
+ bitmap = kvzalloc(bitmap_sz, GFP_KERNEL);
+ if (!bitmap) {
+ err = -ENOMEM;
+ goto out;
+ }
+
old_block_size = block_size(bdev);
err = set_blocksize(bdev, PAGE_SIZE);
if (err)
goto out;
reset_bdev(zram);
+ spin_lock_init(&zram->bitmap_lock);
zram->old_block_size = old_block_size;
zram->bdev = bdev;
zram->backing_dev = backing_dev;
+ zram->bitmap = bitmap;
+ zram->nr_pages = nr_pages;
up_write(&zram->init_lock);
pr_info("setup backing device %s\n", file_name);
@@ -386,6 +401,9 @@ static ssize_t backing_dev_store(struct device *dev,
return len;
out:
+ if (bitmap)
+ kvfree(bitmap);
+
if (bdev)
blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
@@ -399,6 +417,34 @@ out:
return err;
}
+static unsigned long get_entry_bdev(struct zram *zram)
+{
+ unsigned long entry;
+
+ spin_lock(&zram->bitmap_lock);
+ /* skip 0 bit to confuse zram.handle = 0 */
+ entry = find_next_zero_bit(zram->bitmap, zram->nr_pages, 1);
+ if (entry == zram->nr_pages) {
+ spin_unlock(&zram->bitmap_lock);
+ return 0;
+ }
+
+ set_bit(entry, zram->bitmap);
+ spin_unlock(&zram->bitmap_lock);
+
+ return entry;
+}
+
+static void put_entry_bdev(struct zram *zram, unsigned long entry)
+{
+ int was_set;
+
+ spin_lock(&zram->bitmap_lock);
+ was_set = test_and_clear_bit(entry, zram->bitmap);
+ spin_unlock(&zram->bitmap_lock);
+ WARN_ON_ONCE(!was_set);
+}
+
#else
static bool zram_wb_enabled(struct zram *zram) { return false; }
static inline void reset_bdev(struct zram *zram) {};