[PATCH v2] t10-pi: reduce ref tag code duplication

[Caleb Sander Mateos <csander@purestorage.com>]

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 <csander@purestorage.com>
Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>
---
v2:
- Move full_pi_ref_tag() earlier (Christoph)
- Use lower_32_bits() (Christoph)

 include/linux/t10-pi.h | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/include/linux/t10-pi.h b/include/linux/t10-pi.h
index 2c59fe3efcd4..b6c2496866ea 100644
--- a/include/linux/t10-pi.h
+++ b/include/linux/t10-pi.h
@@ -2,10 +2,11 @@
 #ifndef _LINUX_T10_PI_H
 #define _LINUX_T10_PI_H
 
 #include <linux/types.h>
 #include <linux/blk-mq.h>
+#include <linux/wordpart.h>
 
 /*
  * A T10 PI-capable target device can be formatted with different
  * protection schemes.	Currently 0 through 3 are defined:
  *
@@ -23,10 +24,20 @@ enum t10_dif_type {
 	T10_PI_TYPE1_PROTECTION = 0x1,
 	T10_PI_TYPE2_PROTECTION = 0x2,
 	T10_PI_TYPE3_PROTECTION = 0x3,
 };
 
+static inline u64 full_pi_ref_tag(const 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);
+}
+
 /*
  * T10 Protection Information tuple.
  */
 struct t10_pi_tuple {
 	__be16 guard_tag;	/* Checksum */
@@ -37,16 +48,11 @@ 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)
 {
-	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 lower_32_bits(full_pi_ref_tag(rq));
 }
 
 struct crc64_pi_tuple {
 	__be64 guard_tag;
 	__be16 app_tag;
@@ -62,14 +68,9 @@ static inline u64 lower_48_bits(u64 n)
 	return n & ((1ull << 48) - 1);
 }
 
 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
-- 
2.45.2