block: make max_integrity_io_size public

File systems that generate integrity will need this, so move it out
of the block private or blk-mq specific headers.

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>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 18 insertions, 0 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index dec0acaed6e6..11857ae13d10 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1881,6 +1881,24 @@ static inline int bio_split_rw_at(struct bio *bio,
 	return bio_split_io_at(bio, lim, segs, max_bytes, lim->dma_alignment);
 }
 
+/*
+ * Maximum contiguous integrity buffer allocation.
+ */
+#define BLK_INTEGRITY_MAX_SIZE		SZ_2M
+
+/*
+ * Maximum size of I/O that needs a block layer integrity buffer.  Limited
+ * by the number of intervals for which we can fit the integrity buffer into
+ * the buffer size.  Because the buffer is a single segment it is also limited
+ * by the maximum segment size.
+ */
+static inline unsigned int max_integrity_io_size(struct queue_limits *lim)
+{
+	return min_t(unsigned int, lim->max_segment_size,
+		(BLK_INTEGRITY_MAX_SIZE / lim->integrity.metadata_size) <<
+			lim->integrity.interval_exp);
+}
+
 #define DEFINE_IO_COMP_BATCH(name)	struct io_comp_batch name = { }
 
 #endif /* _LINUX_BLKDEV_H */