block: Block layer data integrity support
Some block devices support verifying the integrity of requests by way
of checksums or other protection information that is submitted along
with the I/O.
This patch implements support for generating and verifying integrity
metadata, as well as correctly merging, splitting and cloning bios and
requests that have this extra information attached.
See Documentation/block/data-integrity.txt for more information.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 6a3da67..4a9ed45 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -112,6 +112,7 @@
__REQ_ALLOCED, /* request came from our alloc pool */
__REQ_RW_META, /* metadata io request */
__REQ_COPY_USER, /* contains copies of user pages */
+ __REQ_INTEGRITY, /* integrity metadata has been remapped */
__REQ_NR_BITS, /* stops here */
};
@@ -134,6 +135,7 @@
#define REQ_ALLOCED (1 << __REQ_ALLOCED)
#define REQ_RW_META (1 << __REQ_RW_META)
#define REQ_COPY_USER (1 << __REQ_COPY_USER)
+#define REQ_INTEGRITY (1 << __REQ_INTEGRITY)
#define BLK_MAX_CDB 16
@@ -865,6 +867,109 @@
MODULE_ALIAS("block-major-" __stringify(major) "-*")
+#if defined(CONFIG_BLK_DEV_INTEGRITY)
+
+#define INTEGRITY_FLAG_READ 1 /* verify data integrity on read */
+#define INTEGRITY_FLAG_WRITE 2 /* generate data integrity on write */
+
+struct blk_integrity_exchg {
+ void *prot_buf;
+ void *data_buf;
+ sector_t sector;
+ unsigned int data_size;
+ unsigned short sector_size;
+ const char *disk_name;
+};
+
+typedef void (integrity_gen_fn) (struct blk_integrity_exchg *);
+typedef int (integrity_vrfy_fn) (struct blk_integrity_exchg *);
+typedef void (integrity_set_tag_fn) (void *, void *, unsigned int);
+typedef void (integrity_get_tag_fn) (void *, void *, unsigned int);
+
+struct blk_integrity {
+ integrity_gen_fn *generate_fn;
+ integrity_vrfy_fn *verify_fn;
+ integrity_set_tag_fn *set_tag_fn;
+ integrity_get_tag_fn *get_tag_fn;
+
+ unsigned short flags;
+ unsigned short tuple_size;
+ unsigned short sector_size;
+ unsigned short tag_size;
+
+ const char *name;
+
+ struct kobject kobj;
+};
+
+extern int blk_integrity_register(struct gendisk *, struct blk_integrity *);
+extern void blk_integrity_unregister(struct gendisk *);
+extern int blk_integrity_compare(struct block_device *, struct block_device *);
+extern int blk_rq_map_integrity_sg(struct request *, struct scatterlist *);
+extern int blk_rq_count_integrity_sg(struct request *);
+
+static inline unsigned short blk_integrity_tuple_size(struct blk_integrity *bi)
+{
+ if (bi)
+ return bi->tuple_size;
+
+ return 0;
+}
+
+static inline struct blk_integrity *bdev_get_integrity(struct block_device *bdev)
+{
+ return bdev->bd_disk->integrity;
+}
+
+static inline unsigned int bdev_get_tag_size(struct block_device *bdev)
+{
+ struct blk_integrity *bi = bdev_get_integrity(bdev);
+
+ if (bi)
+ return bi->tag_size;
+
+ return 0;
+}
+
+static inline int bdev_integrity_enabled(struct block_device *bdev, int rw)
+{
+ struct blk_integrity *bi = bdev_get_integrity(bdev);
+
+ if (bi == NULL)
+ return 0;
+
+ if (rw == READ && bi->verify_fn != NULL &&
+ test_bit(INTEGRITY_FLAG_READ, &bi->flags))
+ return 1;
+
+ if (rw == WRITE && bi->generate_fn != NULL &&
+ test_bit(INTEGRITY_FLAG_WRITE, &bi->flags))
+ return 1;
+
+ return 0;
+}
+
+static inline int blk_integrity_rq(struct request *rq)
+{
+ BUG_ON(rq->bio == NULL);
+
+ return bio_integrity(rq->bio);
+}
+
+#else /* CONFIG_BLK_DEV_INTEGRITY */
+
+#define blk_integrity_rq(rq) (0)
+#define blk_rq_count_integrity_sg(a) (0)
+#define blk_rq_map_integrity_sg(a, b) (0)
+#define bdev_get_integrity(a) (0)
+#define bdev_get_tag_size(a) (0)
+#define blk_integrity_compare(a, b) (0)
+#define blk_integrity_register(a, b) (0)
+#define blk_integrity_unregister(a) do { } while (0);
+
+#endif /* CONFIG_BLK_DEV_INTEGRITY */
+
+
#else /* CONFIG_BLOCK */
/*
* stubs for when the block layer is configured out