t10-pi: reduce ref tag code duplication

t10_pi_ref_tag() and ext_pi_ref_tag() are identical except for the final
truncation of the ref tag to 32 or 48 bits. Factor out a helper
full_pi_ref_tag() to return the untruncated ref tag and use it in
t10_pi_ref_tag() and ext_pi_ref_tag().

Signed-off-by: Caleb Sander Mateos <[email protected]>
Reviewed-by: Anuj Gupta <[email protected]>

Author: calebsander

include/linux/t10-pi.h

@@ -37,14 +37,19 @@ struct t10_pi_tuple {
 #define T10_PI_APP_ESCAPE cpu_to_be16(0xffff)
 #define T10_PI_REF_ESCAPE cpu_to_be32(0xffffffff)
 
-static inline u32 t10_pi_ref_tag(struct request *rq)
+static inline u64 full_pi_ref_tag(struct request *rq)
 {
 	unsigned int shift = ilog2(queue_logical_block_size(rq->q));
 
 	if (IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY) &&
 	    rq->q->limits.integrity.interval_exp)
 		shift = rq->q->limits.integrity.interval_exp;
-	return blk_rq_pos(rq) >> (shift - SECTOR_SHIFT) & 0xffffffff;
+	return blk_rq_pos(rq) >> (shift - SECTOR_SHIFT);
+}
+
+static inline u32 t10_pi_ref_tag(struct request *rq)
+{
+	return full_pi_ref_tag(rq) & 0xffffffff;
 }
 
 struct crc64_pi_tuple {
@@ -64,12 +69,7 @@ static inline u64 lower_48_bits(u64 n)
 
 static inline u64 ext_pi_ref_tag(struct request *rq)
 {
-	unsigned int shift = ilog2(queue_logical_block_size(rq->q));
-
-	if (IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY) &&
-	    rq->q->limits.integrity.interval_exp)
-		shift = rq->q->limits.integrity.interval_exp;
-	return lower_48_bits(blk_rq_pos(rq) >> (shift - SECTOR_SHIFT));
+	return lower_48_bits(full_pi_ref_tag(rq));
 }
 
 #endif