block: centralize PI remapping logic to the block layer

Currently t10_pi_prepare/t10_pi_complete functions are called during the
NVMe and SCSi layers command preparetion/completion, but their actual
place should be the block layer since T10-PI is a general data integrity
feature that is used by block storage protocols. Introduce .prepare_fn
and .complete_fn callbacks within the integrity profile that each type
can implement according to its needs.

Suggested-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Suggested-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Max Gurtovoy <maxg@mellanox.com>

Fixed to not call queue integrity functions if BLK_DEV_INTEGRITY
isn't defined in the config.

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

1 files changed, 6 insertions, 0 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 20a49be536b5..29275f5a996f 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -30,6 +30,7 @@
 #include <trace/events/block.h>
 
 #include <linux/blk-mq.h>
+#include <linux/t10-pi.h>
 #include "blk.h"
 #include "blk-mq.h"
 #include "blk-mq-debugfs.h"
@@ -700,6 +701,11 @@ void blk_mq_start_request(struct request *rq)
                  */
                 rq->nr_phys_segments++;
         }
+
+#ifdef CONFIG_BLK_DEV_INTEGRITY
+        if (blk_integrity_rq(rq) && req_op(rq) == REQ_OP_WRITE)
+                q->integrity.profile->prepare_fn(rq);
+#endif
 }
 EXPORT_SYMBOL(blk_mq_start_request);