return len;
}
- bio->bi_bdev = zram->bdev;
+#ifdef CONFIG_ZRAM_WRITEBACK
+static bool zram_wb_enabled(struct zram *zram)
+{
+ return zram->backing_dev;
+}
+
+static void reset_bdev(struct zram *zram)
+{
+ struct block_device *bdev;
+
+ if (!zram_wb_enabled(zram))
+ return;
+
+ bdev = zram->bdev;
+ if (zram->old_block_size)
+ set_blocksize(bdev, zram->old_block_size);
+ blkdev_put(bdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);
+ /* hope filp_close flush all of IO */
+ filp_close(zram->backing_dev, NULL);
+ 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,
+ struct device_attribute *attr, char *buf)
+{
+ struct zram *zram = dev_to_zram(dev);
+ struct file *file = zram->backing_dev;
+ char *p;
+ ssize_t ret;
+
+ down_read(&zram->init_lock);
+ if (!zram_wb_enabled(zram)) {
+ memcpy(buf, "none\n", 5);
+ up_read(&zram->init_lock);
+ return 5;
+ }
+
+ p = file_path(file, buf, PAGE_SIZE - 1);
+ if (IS_ERR(p)) {
+ ret = PTR_ERR(p);
+ goto out;
+ }
+
+ ret = strlen(p);
+ memmove(buf, p, ret);
+ buf[ret++] = '\n';
+out:
+ up_read(&zram->init_lock);
+ return ret;
+}
+
+static ssize_t backing_dev_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ char *file_name;
+ struct file *backing_dev = NULL;
+ struct inode *inode;
+ struct address_space *mapping;
+ 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);
+
+ file_name = kmalloc(PATH_MAX, GFP_KERNEL);
+ if (!file_name)
+ return -ENOMEM;
+
+ down_write(&zram->init_lock);
+ if (init_done(zram)) {
+ pr_info("Can't setup backing device for initialized device\n");
+ err = -EBUSY;
+ goto out;
+ }
+
+ strlcpy(file_name, buf, len);
+
+ backing_dev = filp_open(file_name, O_RDWR|O_LARGEFILE, 0);
+ if (IS_ERR(backing_dev)) {
+ err = PTR_ERR(backing_dev);
+ backing_dev = NULL;
+ goto out;
+ }
+
+ mapping = backing_dev->f_mapping;
+ inode = mapping->host;
+
+ /* Support only block device in this moment */
+ if (!S_ISBLK(inode->i_mode)) {
+ err = -ENOTBLK;
+ goto out;
+ }
+
+ bdev = bdgrab(I_BDEV(inode));
+ err = blkdev_get(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL, zram);
+ 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);
+ kfree(file_name);
+
+ return len;
+out:
+ if (bitmap)
+ kvfree(bitmap);
+
+ if (bdev)
+ blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+
+ if (backing_dev)
+ filp_close(backing_dev, NULL);
+
+ up_write(&zram->init_lock);
+
+ kfree(file_name);
+
+ 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);
+}
+
+void zram_page_end_io(struct bio *bio)
+{
+ struct page *page = bio->bi_io_vec[0].bv_page;
+
+ page_endio(page, op_is_write(bio_op(bio)),
+ blk_status_to_errno(bio->bi_status));
+ bio_put(bio);
+}
+
+/*
+ * Returns 1 if the submission is successful.
+ */
+static int read_from_bdev_async(struct zram *zram, struct bio_vec *bvec,
+ unsigned long entry, struct bio *parent)
+{
+ struct bio *bio;
+
+ bio = bio_alloc(GFP_ATOMIC, 1);
+ if (!bio)
+ return -ENOMEM;
+
+ bio->bi_iter.bi_sector = entry * (PAGE_SIZE >> 9);
- bio->bi_bdev = zram->bdev;
++ bio_set_dev(bio, zram->bdev);
+ if (!bio_add_page(bio, bvec->bv_page, bvec->bv_len, bvec->bv_offset)) {
+ bio_put(bio);
+ return -EIO;
+ }
+
+ if (!parent) {
+ bio->bi_opf = REQ_OP_READ;
+ bio->bi_end_io = zram_page_end_io;
+ } else {
+ bio->bi_opf = parent->bi_opf;
+ bio_chain(bio, parent);
+ }
+
+ submit_bio(bio);
+ return 1;
+}
+
+struct zram_work {
+ struct work_struct work;
+ struct zram *zram;
+ unsigned long entry;
+ struct bio *bio;
+};
+
+#if PAGE_SIZE != 4096
+static void zram_sync_read(struct work_struct *work)
+{
+ struct bio_vec bvec;
+ struct zram_work *zw = container_of(work, struct zram_work, work);
+ struct zram *zram = zw->zram;
+ unsigned long entry = zw->entry;
+ struct bio *bio = zw->bio;
+
+ read_from_bdev_async(zram, &bvec, entry, bio);
+}
+
+/*
+ * Block layer want one ->make_request_fn to be active at a time
+ * so if we use chained IO with parent IO in same context,
+ * it's a deadlock. To avoid, it, it uses worker thread context.
+ */
+static int read_from_bdev_sync(struct zram *zram, struct bio_vec *bvec,
+ unsigned long entry, struct bio *bio)
+{
+ struct zram_work work;
+
+ work.zram = zram;
+ work.entry = entry;
+ work.bio = bio;
+
+ INIT_WORK_ONSTACK(&work.work, zram_sync_read);
+ queue_work(system_unbound_wq, &work.work);
+ flush_work(&work.work);
+ destroy_work_on_stack(&work.work);
+
+ return 1;
+}
+#else
+static int read_from_bdev_sync(struct zram *zram, struct bio_vec *bvec,
+ unsigned long entry, struct bio *bio)
+{
+ WARN_ON(1);
+ return -EIO;
+}
+#endif
+
+static int read_from_bdev(struct zram *zram, struct bio_vec *bvec,
+ unsigned long entry, struct bio *parent, bool sync)
+{
+ if (sync)
+ return read_from_bdev_sync(zram, bvec, entry, parent);
+ else
+ return read_from_bdev_async(zram, bvec, entry, parent);
+}
+
+static int write_to_bdev(struct zram *zram, struct bio_vec *bvec,
+ u32 index, struct bio *parent,
+ unsigned long *pentry)
+{
+ struct bio *bio;
+ unsigned long entry;
+
+ bio = bio_alloc(GFP_ATOMIC, 1);
+ if (!bio)
+ return -ENOMEM;
+
+ entry = get_entry_bdev(zram);
+ if (!entry) {
+ bio_put(bio);
+ return -ENOSPC;
+ }
+
+ bio->bi_iter.bi_sector = entry * (PAGE_SIZE >> 9);
++ bio_set_dev(bio, zram->bdev);
+ if (!bio_add_page(bio, bvec->bv_page, bvec->bv_len,
+ bvec->bv_offset)) {
+ bio_put(bio);
+ put_entry_bdev(zram, entry);
+ return -EIO;
+ }
+
+ if (!parent) {
+ bio->bi_opf = REQ_OP_WRITE | REQ_SYNC;
+ bio->bi_end_io = zram_page_end_io;
+ } else {
+ bio->bi_opf = parent->bi_opf;
+ bio_chain(bio, parent);
+ }
+
+ submit_bio(bio);
+ *pentry = entry;
+
+ return 0;
+}
+
+static void zram_wb_clear(struct zram *zram, u32 index)
+{
+ unsigned long entry;
+
+ zram_clear_flag(zram, index, ZRAM_WB);
+ entry = zram_get_element(zram, index);
+ zram_set_element(zram, index, 0);
+ put_entry_bdev(zram, entry);
+}
+
+#else
+static bool zram_wb_enabled(struct zram *zram) { return false; }
+static inline void reset_bdev(struct zram *zram) {};
+static int write_to_bdev(struct zram *zram, struct bio_vec *bvec,
+ u32 index, struct bio *parent,
+ unsigned long *pentry)
+
+{
+ return -EIO;
+}
+
+static int read_from_bdev(struct zram *zram, struct bio_vec *bvec,
+ unsigned long entry, struct bio *parent, bool sync)
+{
+ return -EIO;
+}
+static void zram_wb_clear(struct zram *zram, u32 index) {}
+#endif
+
+
/*
* We switched to per-cpu streams and this attr is not needed anymore.
* However, we will keep it around for some time, because:
flush_dcache_page(bvec->bv_page);
} else {
atomic64_inc(&zram->stats.num_writes);
- ret = zram_bvec_write(zram, bvec, index, offset);
+ ret = zram_bvec_write(zram, bvec, index, offset, bio);
}
- generic_end_io_acct(rw_acct, &zram->disk->part0, start_time);
+ generic_end_io_acct(q, rw_acct, &zram->disk->part0, start_time);
- if (unlikely(ret)) {
+ if (unlikely(ret < 0)) {
if (!is_write)
atomic64_inc(&zram->stats.failed_reads);
else
projects / users / jedix / linux-maple.git / commitdiff