[PATCH v4 2/3] block: move dif_prepare/dif_complete functions to block layer

Max Gurtovoy
2018-07-25T15:46:16Z

Currently these functions are implemented in the scsi layer, but their
actual place should be the block layer since T10-PI is a general data
integrity feature that is used in the nvme protocol as well. Also, use
the tuple size from the integrity profile since it may vary between
integrity types.

Suggested-by: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
---

changes from v3:
- kmap_atomic/kunmap_atomic the same address
- declare pi struct inside the inner for loop
- check "intervals" inside the for loop condition

changes from v2:
- convert comments to kerneldoc format
- removed SCSI specific comment
- fix kmap_atomic/kunmap_atomic addresses
- fix iteration over t10_pi_tuple's

changes from v1 (Christoph, Martin and Keith comments):
- moved the functions to t10-pi.c
- updated tuple size
- changed local variables scope
- remove/add new lines

---
block/t10-pi.c | 110 +++++++++++++++++++++++++++++++++++++++++++++++
drivers/scsi/sd.c | 8 ++--
drivers/scsi/sd.h | 9 ----
drivers/scsi/sd_dif.c | 113 -------------------------------------------------
include/linux/t10-pi.h | 3 ++
5 files changed, 118 insertions(+), 125 deletions(-)

diff --git a/block/t10-pi.c b/block/t10-pi.c
index a98db38..62aed77 100644
--- a/block/t10-pi.c
+++ b/block/t10-pi.c
@@ -184,3 +184,113 @@ static blk_status_t t10_pi_type3_verify_ip(struct blk_integrity_iter *iter)
.verify_fn = t10_pi_type3_verify_ip,
};
EXPORT_SYMBOL(t10_pi_type3_ip);
+
+/**
+ * t10_pi_prepare - prepare PI prior submitting request to device
+ * @rq: request with PI that should be prepared
+ * @protection_type: PI type (Type 1/Type 2/Type 3)
+ *
+ * For Type 1/Type 2, the virtual start sector is the one that was
+ * originally submitted by the block layer for the ref_tag usage. Due to
+ * partitioning, MD/DM cloning, etc. the actual physical start sector is
+ * likely to be different. Remap protection information to match the
+ * physical LBA.
+ *
+ * Type 3 does not have a reference tag so no remapping is required.
+ */
+void t10_pi_prepare(struct request *rq, u8 protection_type)
+{
+ const int tuple_sz = rq->q->integrity.tuple_size;
+ u32 ref_tag = t10_pi_ref_tag(rq);
+ struct bio *bio;
+
+ if (protection_type == T10_PI_TYPE3_PROTECTION)
+ return;
+
+ __rq_for_each_bio(bio, rq) {
+ struct bio_integrity_payload *bip = bio_integrity(bio);
+ u32 virt = bip_get_seed(bip) & 0xffffffff;
+ struct bio_vec iv;
+ struct bvec_iter iter;
+
+ /* Already remapped? */
+ if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
+ break;
+
+ bip_for_each_vec(iv, bip, iter) {
+ void *p, *pmap;
+ unsigned int j;
+
+ pmap = kmap_atomic(iv.bv_page);
+ p = pmap + iv.bv_offset;
+ for (j = 0; j < iv.bv_len; j += tuple_sz) {
+ struct t10_pi_tuple *pi = p;
+
+ if (be32_to_cpu(pi->ref_tag) == virt)
+ pi->ref_tag = cpu_to_be32(ref_tag);
+ virt++;
+ ref_tag++;
+ p += tuple_sz;
+ }
+
+ kunmap_atomic(pmap);
+ }
+
+ bip->bip_flags |= BIP_MAPPED_INTEGRITY;
+ }
+}
+EXPORT_SYMBOL(t10_pi_prepare);
+
+/**
+ * t10_pi_complete - prepare PI prior returning request to the block layer
+ * @rq: request with PI that should be prepared
+ * @protection_type: PI type (Type 1/Type 2/Type 3)
+ * @intervals: total elements to prepare
+ *
+ * For Type 1/Type 2, the virtual start sector is the one that was
+ * originally submitted by the block layer for the ref_tag usage. Due to
+ * partitioning, MD/DM cloning, etc. the actual physical start sector is
+ * likely to be different. Since the physical start sector was submitted
+ * to the device, we should remap it back to virtual values expected by the
+ * block layer.
+ *
+ * Type 3 does not have a reference tag so no remapping is required.
+ */
+void t10_pi_complete(struct request *rq, u8 protection_type,
+ unsigned int intervals)
+{
+ const int tuple_sz = rq->q->integrity.tuple_size;
+ u32 ref_tag = t10_pi_ref_tag(rq);
+ struct bio *bio;
+
+ if (protection_type == T10_PI_TYPE3_PROTECTION)
+ return;
+
+ __rq_for_each_bio(bio, rq) {
+ struct bio_integrity_payload *bip = bio_integrity(bio);
+ u32 virt = bip_get_seed(bip) & 0xffffffff;
+ struct bio_vec iv;
+ struct bvec_iter iter;
+
+ bip_for_each_vec(iv, bip, iter) {
+ void *p, *pmap;
+ unsigned int j;
+
+ pmap = kmap_atomic(iv.bv_page);
+ p = pmap + iv.bv_offset;
+ for (j = 0; j < iv.bv_len && intervals; j += tuple_sz) {
+ struct t10_pi_tuple *pi = p;
+
+ if (be32_to_cpu(pi->ref_tag) == ref_tag)
+ pi->ref_tag = cpu_to_be32(virt);
+ virt++;
+ ref_tag++;
+ intervals--;
+ p += tuple_sz;
+ }
+
+ kunmap_atomic(pmap);
+ }
+ }
+}
+EXPORT_SYMBOL(t10_pi_complete);
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 9421d98..bbebdc3 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1119,7 +1119,7 @@ static int sd_setup_read_write_cmnd(struct scsi_cmnd *SCpnt)
SCpnt->cmnd[0] = WRITE_6;

if (blk_integrity_rq(rq))
- sd_dif_prepare(SCpnt);
+ t10_pi_prepare(SCpnt->request, sdkp->protection_type);

} else if (rq_data_dir(rq) == READ) {
SCpnt->cmnd[0] = READ_6;
@@ -2047,8 +2047,10 @@ static int sd_done(struct scsi_cmnd *SCpnt)
"sd_done: completed %d of %d bytes\n",
good_bytes, scsi_bufflen(SCpnt)));

- if (rq_data_dir(SCpnt->request) == READ && scsi_prot_sg_count(SCpnt))
- sd_dif_complete(SCpnt, good_bytes);
+ if (rq_data_dir(SCpnt->request) == READ && scsi_prot_sg_count(SCpnt) &&
+ good_bytes)
+ t10_pi_complete(SCpnt->request, sdkp->protection_type,
+ good_bytes / scsi_prot_interval(SCpnt));

return good_bytes;
}
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 392c7d0..a7d4f50 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -254,21 +254,12 @@ static inline unsigned int sd_prot_flag_mask(unsigned int prot_op)
#ifdef CONFIG_BLK_DEV_INTEGRITY

extern void sd_dif_config_host(struct scsi_disk *);
-extern void sd_dif_prepare(struct scsi_cmnd *scmd);
-extern void sd_dif_complete(struct scsi_cmnd *, unsigned int);

#else /* CONFIG_BLK_DEV_INTEGRITY */

static inline void sd_dif_config_host(struct scsi_disk *disk)
{
}
-static inline int sd_dif_prepare(struct scsi_cmnd *scmd)
-{
- return 0;
-}
-static inline void sd_dif_complete(struct scsi_cmnd *cmd, unsigned int a)
-{
-}

#endif /* CONFIG_BLK_DEV_INTEGRITY */

diff --git a/drivers/scsi/sd_dif.c b/drivers/scsi/sd_dif.c
index d8de43d..db72c82 100644
--- a/drivers/scsi/sd_dif.c
+++ b/drivers/scsi/sd_dif.c
@@ -95,116 +95,3 @@ void sd_dif_config_host(struct scsi_disk *sdkp)
blk_integrity_register(disk, &bi);
}

-/*
- * The virtual start sector is the one that was originally submitted
- * by the block layer. Due to partitioning, MD/DM cloning, etc. the
- * actual physical start sector is likely to be different. Remap
- * protection information to match the physical LBA.
- *
- * From a protocol perspective there's a slight difference between
- * Type 1 and 2. The latter uses 32-byte CDBs exclusively, and the
- * reference tag is seeded in the CDB. This gives us the potential to
- * avoid virt->phys remapping during write. However, at read time we
- * don't know whether the virt sector is the same as when we wrote it
- * (we could be reading from real disk as opposed to MD/DM device. So
- * we always remap Type 2 making it identical to Type 1.
- *
- * Type 3 does not have a reference tag so no remapping is required.
- */
-void sd_dif_prepare(struct scsi_cmnd *scmd)
-{
- const int tuple_sz = sizeof(struct t10_pi_tuple);
- struct bio *bio;
- struct scsi_disk *sdkp;
- struct t10_pi_tuple *pi;
- u32 phys, virt;
-
- sdkp = scsi_disk(scmd->request->rq_disk);
-
- if (sdkp->protection_type == T10_PI_TYPE3_PROTECTION)
- return;
-
- phys = t10_pi_ref_tag(scmd->request);
-
- __rq_for_each_bio(bio, scmd->request) {
- struct bio_integrity_payload *bip = bio_integrity(bio);
- struct bio_vec iv;
- struct bvec_iter iter;
- unsigned int j;
-
- /* Already remapped? */
- if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
- break;
-
- virt = bip_get_seed(bip) & 0xffffffff;
-
- bip_for_each_vec(iv, bip, iter) {
- pi = kmap_atomic(iv.bv_page) + iv.bv_offset;
-
- for (j = 0; j < iv.bv_len; j += tuple_sz, pi++) {
-
- if (be32_to_cpu(pi->ref_tag) == virt)
- pi->ref_tag = cpu_to_be32(phys);
-
- virt++;
- phys++;
- }
-
- kunmap_atomic(pi);
- }
-
- bip->bip_flags |= BIP_MAPPED_INTEGRITY;
- }
-}
-
-/*
- * Remap physical sector values in the reference tag to the virtual
- * values expected by the block layer.
- */
-void sd_dif_complete(struct scsi_cmnd *scmd, unsigned int good_bytes)
-{
- const int tuple_sz = sizeof(struct t10_pi_tuple);
- struct scsi_disk *sdkp;
- struct bio *bio;
- struct t10_pi_tuple *pi;
- unsigned int j, intervals;
- u32 phys, virt;
-
- sdkp = scsi_disk(scmd->request->rq_disk);
-
- if (sdkp->protection_type == T10_PI_TYPE3_PROTECTION || good_bytes == 0)
- return;
-
- intervals = good_bytes / scsi_prot_interval(scmd);
- phys = t10_pi_ref_tag(scmd->request);
-
- __rq_for_each_bio(bio, scmd->request) {
- struct bio_integrity_payload *bip = bio_integrity(bio);
- struct bio_vec iv;
- struct bvec_iter iter;
-
- virt = bip_get_seed(bip) & 0xffffffff;
-
- bip_for_each_vec(iv, bip, iter) {
- pi = kmap_atomic(iv.bv_page) + iv.bv_offset;
-
- for (j = 0; j < iv.bv_len; j += tuple_sz, pi++) {
-
- if (intervals == 0) {
- kunmap_atomic(pi);
- return;
- }
-
- if (be32_to_cpu(pi->ref_tag) == phys)
- pi->ref_tag = cpu_to_be32(virt);
-
- virt++;
- phys++;
- intervals--;
- }
-
- kunmap_atomic(pi);
- }
- }
-}
-
diff --git a/include/linux/t10-pi.h b/include/linux/t10-pi.h
index 635855e..81ae4c4 100644
--- a/include/linux/t10-pi.h
+++ b/include/linux/t10-pi.h
@@ -47,5 +47,8 @@ static inline u32 t10_pi_ref_tag(struct request *rq)
extern const struct blk_integrity_profile t10_pi_type1_ip;
extern const struct blk_integrity_profile t10_pi_type3_crc;
extern const struct blk_integrity_profile t10_pi_type3_ip;
+extern void t10_pi_prepare(struct request *rq, u8 protection_type);
+extern void t10_pi_complete(struct request *rq, u8 protection_type,
+ unsigned int intervals);

#endif
--
1.8.3.1