block: only zero non-PI metadata tuples in bio_integrity_prep

The PI generation helpers already zero the app tag, so relax the zeroing
to non-PI metadata.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20240626045950.189758-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: Christoph Hellwig

block/bio-integrity.c

@@ -456,11 +456,11 @@ bool bio_integrity_prep(struct bio *bio)
 
 		/*
 		 * Zero the memory allocated to not leak uninitialized kernel
-		 * memory to disk.  For PI this only affects the app tag, but
-		 * for non-integrity metadata it affects the entire metadata
-		 * buffer.
+		 * memory to disk for non-integrity metadata where nothing else
+		 * initializes the memory.
 		 */
-		gfp |= __GFP_ZERO;
+		if (bi->csum_type == BLK_INTEGRITY_CSUM_NONE)
+			gfp |= __GFP_ZERO;
 	}
 
 	/* Allocate kernel buffer for protection data */