v4.19.13 snapshot.
diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
new file mode 100644
index 0000000..0959044
--- /dev/null
+++ b/fs/crypto/bio.c
@@ -0,0 +1,155 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This contains encryption functions for per-file encryption.
+ *
+ * Copyright (C) 2015, Google, Inc.
+ * Copyright (C) 2015, Motorola Mobility
+ *
+ * Written by Michael Halcrow, 2014.
+ *
+ * Filename encryption additions
+ * Uday Savagaonkar, 2014
+ * Encryption policy handling additions
+ * Ildar Muslukhov, 2014
+ * Add fscrypt_pullback_bio_page()
+ * Jaegeuk Kim, 2015.
+ *
+ * This has not yet undergone a rigorous security audit.
+ *
+ * The usage of AES-XTS should conform to recommendations in NIST
+ * Special Publication 800-38E and IEEE P1619/D16.
+ */
+
+#include <linux/pagemap.h>
+#include <linux/module.h>
+#include <linux/bio.h>
+#include <linux/namei.h>
+#include "fscrypt_private.h"
+
+static void __fscrypt_decrypt_bio(struct bio *bio, bool done)
+{
+ struct bio_vec *bv;
+ int i;
+
+ bio_for_each_segment_all(bv, bio, i) {
+ struct page *page = bv->bv_page;
+ int ret = fscrypt_decrypt_page(page->mapping->host, page,
+ PAGE_SIZE, 0, page->index);
+
+ if (ret) {
+ WARN_ON_ONCE(1);
+ SetPageError(page);
+ } else if (done) {
+ SetPageUptodate(page);
+ }
+ if (done)
+ unlock_page(page);
+ }
+}
+
+void fscrypt_decrypt_bio(struct bio *bio)
+{
+ __fscrypt_decrypt_bio(bio, false);
+}
+EXPORT_SYMBOL(fscrypt_decrypt_bio);
+
+static void completion_pages(struct work_struct *work)
+{
+ struct fscrypt_ctx *ctx =
+ container_of(work, struct fscrypt_ctx, r.work);
+ struct bio *bio = ctx->r.bio;
+
+ __fscrypt_decrypt_bio(bio, true);
+ fscrypt_release_ctx(ctx);
+ bio_put(bio);
+}
+
+void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx, struct bio *bio)
+{
+ INIT_WORK(&ctx->r.work, completion_pages);
+ ctx->r.bio = bio;
+ fscrypt_enqueue_decrypt_work(&ctx->r.work);
+}
+EXPORT_SYMBOL(fscrypt_enqueue_decrypt_bio);
+
+void fscrypt_pullback_bio_page(struct page **page, bool restore)
+{
+ struct fscrypt_ctx *ctx;
+ struct page *bounce_page;
+
+ /* The bounce data pages are unmapped. */
+ if ((*page)->mapping)
+ return;
+
+ /* The bounce data page is unmapped. */
+ bounce_page = *page;
+ ctx = (struct fscrypt_ctx *)page_private(bounce_page);
+
+ /* restore control page */
+ *page = ctx->w.control_page;
+
+ if (restore)
+ fscrypt_restore_control_page(bounce_page);
+}
+EXPORT_SYMBOL(fscrypt_pullback_bio_page);
+
+int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
+ sector_t pblk, unsigned int len)
+{
+ struct fscrypt_ctx *ctx;
+ struct page *ciphertext_page = NULL;
+ struct bio *bio;
+ int ret, err = 0;
+
+ BUG_ON(inode->i_sb->s_blocksize != PAGE_SIZE);
+
+ ctx = fscrypt_get_ctx(inode, GFP_NOFS);
+ if (IS_ERR(ctx))
+ return PTR_ERR(ctx);
+
+ ciphertext_page = fscrypt_alloc_bounce_page(ctx, GFP_NOWAIT);
+ if (IS_ERR(ciphertext_page)) {
+ err = PTR_ERR(ciphertext_page);
+ goto errout;
+ }
+
+ while (len--) {
+ err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk,
+ ZERO_PAGE(0), ciphertext_page,
+ PAGE_SIZE, 0, GFP_NOFS);
+ if (err)
+ goto errout;
+
+ bio = bio_alloc(GFP_NOWAIT, 1);
+ if (!bio) {
+ err = -ENOMEM;
+ goto errout;
+ }
+ bio_set_dev(bio, inode->i_sb->s_bdev);
+ bio->bi_iter.bi_sector =
+ pblk << (inode->i_sb->s_blocksize_bits - 9);
+ bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
+ ret = bio_add_page(bio, ciphertext_page,
+ inode->i_sb->s_blocksize, 0);
+ if (ret != inode->i_sb->s_blocksize) {
+ /* should never happen! */
+ WARN_ON(1);
+ bio_put(bio);
+ err = -EIO;
+ goto errout;
+ }
+ err = submit_bio_wait(bio);
+ if (err == 0 && bio->bi_status)
+ err = -EIO;
+ bio_put(bio);
+ if (err)
+ goto errout;
+ lblk++;
+ pblk++;
+ }
+ err = 0;
+errout:
+ fscrypt_release_ctx(ctx);
+ return err;
+}
+EXPORT_SYMBOL(fscrypt_zeroout_range);