[PATCH 06/16] block: add fs_bio_integrity helpers

[Christoph Hellwig <hch@lst.de>]

Add a set of helpers for file system initiated integrity information.
These include mempool backed allocations and verifying based on a passed
in sector and size which is often available from file system completion
routines.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Tested-by: Anuj Gupta <anuj20.g@samsung.com>
---
 block/Makefile                |  2 +-
 block/bio-integrity-fs.c      | 81 +++++++++++++++++++++++++++++++++++
 include/linux/bio-integrity.h |  6 +++
 3 files changed, 88 insertions(+), 1 deletion(-)
 create mode 100644 block/bio-integrity-fs.c

diff --git a/block/Makefile b/block/Makefile
index c65f4da93702..7dce2e44276c 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -26,7 +26,7 @@ bfq-y				:= bfq-iosched.o bfq-wf2q.o bfq-cgroup.o
 obj-$(CONFIG_IOSCHED_BFQ)	+= bfq.o
 
 obj-$(CONFIG_BLK_DEV_INTEGRITY) += bio-integrity.o blk-integrity.o t10-pi.o \
-				   bio-integrity-auto.o
+				   bio-integrity-auto.o bio-integrity-fs.o
 obj-$(CONFIG_BLK_DEV_ZONED)	+= blk-zoned.o
 obj-$(CONFIG_BLK_WBT)		+= blk-wbt.o
 obj-$(CONFIG_BLK_DEBUG_FS)	+= blk-mq-debugfs.o
diff --git a/block/bio-integrity-fs.c b/block/bio-integrity-fs.c
new file mode 100644
index 000000000000..acb1e5f270d2
--- /dev/null
+++ b/block/bio-integrity-fs.c
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2025 Christoph Hellwig.
+ */
+#include <linux/blk-integrity.h>
+#include <linux/bio-integrity.h>
+#include "blk.h"
+
+struct fs_bio_integrity_buf {
+	struct bio_integrity_payload	bip;
+	struct bio_vec			bvec;
+};
+
+static struct kmem_cache *fs_bio_integrity_cache;
+static mempool_t fs_bio_integrity_pool;
+
+unsigned int fs_bio_integrity_alloc(struct bio *bio)
+{
+	struct fs_bio_integrity_buf *iib;
+	unsigned int action;
+
+	action = bio_integrity_action(bio);
+	if (!action)
+		return 0;
+
+	iib = mempool_alloc(&fs_bio_integrity_pool, GFP_NOIO);
+	bio_integrity_init(bio, &iib->bip, &iib->bvec, 1);
+
+	bio_integrity_alloc_buf(bio, action & BI_ACT_ZERO);
+	if (action & BI_ACT_CHECK)
+		bio_integrity_setup_default(bio);
+	return action;
+}
+
+void fs_bio_integrity_free(struct bio *bio)
+{
+	struct bio_integrity_payload *bip = bio_integrity(bio);
+
+	bio_integrity_free_buf(bip);
+	mempool_free(container_of(bip, struct fs_bio_integrity_buf, bip),
+			&fs_bio_integrity_pool);
+
+	bio->bi_integrity = NULL;
+	bio->bi_opf &= ~REQ_INTEGRITY;
+}
+
+void fs_bio_integrity_generate(struct bio *bio)
+{
+	if (fs_bio_integrity_alloc(bio))
+		bio_integrity_generate(bio);
+}
+EXPORT_SYMBOL_GPL(fs_bio_integrity_generate);
+
+int fs_bio_integrity_verify(struct bio *bio, sector_t sector, unsigned int size)
+{
+	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
+	struct bio_integrity_payload *bip = bio_integrity(bio);
+
+	/*
+	 * Reinitialize bip->bip_iter.
+	 *
+	 * This is for use in the submitter after the driver is done with the
+	 * bio.  Requires the submitter to remember the sector and the size.
+	 */
+	memset(&bip->bip_iter, 0, sizeof(bip->bip_iter));
+	bip->bip_iter.bi_sector = sector;
+	bip->bip_iter.bi_size = bio_integrity_bytes(bi, size >> SECTOR_SHIFT);
+	return blk_status_to_errno(bio_integrity_verify(bio, &bip->bip_iter));
+}
+
+static int __init fs_bio_integrity_init(void)
+{
+	fs_bio_integrity_cache = kmem_cache_create("fs_bio_integrity",
+			sizeof(struct fs_bio_integrity_buf), 0,
+			SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
+	if (mempool_init_slab_pool(&fs_bio_integrity_pool, BIO_POOL_SIZE,
+			fs_bio_integrity_cache))
+		panic("fs_bio_integrity: can't create pool\n");
+	return 0;
+}
+fs_initcall(fs_bio_integrity_init);
diff --git a/include/linux/bio-integrity.h b/include/linux/bio-integrity.h
index 232b86b9bbcb..af5178434ec6 100644
--- a/include/linux/bio-integrity.h
+++ b/include/linux/bio-integrity.h
@@ -145,4 +145,10 @@ void bio_integrity_alloc_buf(struct bio *bio, bool zero_buffer);
 void bio_integrity_free_buf(struct bio_integrity_payload *bip);
 void bio_integrity_setup_default(struct bio *bio);
 
+unsigned int fs_bio_integrity_alloc(struct bio *bio);
+void fs_bio_integrity_free(struct bio *bio);
+void fs_bio_integrity_generate(struct bio *bio);
+int fs_bio_integrity_verify(struct bio *bio, sector_t sector,
+		unsigned int size);
+
 #endif /* _LINUX_BIO_INTEGRITY_H */
-- 
2.47.3