Re: [PATCH 05/14] block: Deprecate the use of the term sector in the context of block integrity

Thu, 03 Jul 2014 02:37:19 -0700 

On 5/29/2014 6:28 AM, Martin K. Petersen wrote:

The protection interval is not necessarily tied to the logical block
size of a block device. Stop using the terms sector and sectors.

Signed-off-by: Martin K. Petersen <martin.peter...@oracle.com>
---
  block/bio-integrity.c  | 46 +++++++++++++++++++++-------------------------
  block/blk-integrity.c  | 10 +++++-----
  drivers/scsi/sd_dif.c  | 46 +++++++++++++++++++++++-----------------------
  include/linux/blkdev.h |  6 +++---
  4 files changed, 52 insertions(+), 56 deletions(-)

diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index e06b3c807eef..c52a8fd98706 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -191,29 +191,25 @@ bool bio_integrity_enabled(struct bio *bio)
  EXPORT_SYMBOL(bio_integrity_enabled);
/** 
- * bio_integrity_hw_sectors - Convert 512b sectors to hardware ditto
+ * bio_integrity_intervals - Return number of integrity intervals for a bio
   * @bi:               blk_integrity profile for device
- * @sectors:   Number of 512 sectors to convert
+ * @sectors:   Size of the bio in 512-byte sectors
   *
   * Description: The block layer calculates everything in 512 byte
- * sectors but integrity metadata is done in terms of the hardware
- * sector size of the storage device.  Convert the block layer sectors
- * to physical sectors.
+ * sectors but integrity metadata is done in terms of the data integrity
+ * interval size of the storage device.  Convert the block layer sectors
+ * to the appropriate number of integrity intervals.
   */
-static inline unsigned int bio_integrity_hw_sectors(struct blk_integrity *bi,
-                                                   unsigned int sectors)
+static inline unsigned int bio_integrity_intervals(struct blk_integrity *bi,
+                                                  unsigned int sectors)
  {
-       /* At this point there are only 512b or 4096b DIF/EPP devices */
-       if (bi->sector_size == 4096)
-               return sectors >>= 3;
-
-       return sectors;
+       return sectors >> (ilog2(bi->interval) - 9);
  }
Now that protection information interval does not necessarily match the sector_size, should this routine protect against bogus bi->interval (e.g. fail if bi->interval < sector_size for example)? Not sure if this check is really needed here, but it might be useful to have (although protection interval 
is still effectively sector_size).
static inline unsigned int bio_integrity_bytes(struct blk_integrity *bi, 
                                               unsigned int sectors)
  {
-       return bio_integrity_hw_sectors(bi, sectors) * bi->tuple_size;
+       return bio_integrity_intervals(bi, sectors) * bi->tuple_size;
  }
/** 
@@ -227,25 +223,25 @@ static int bio_integrity_generate_verify(struct bio *bio, 
int operate)
        struct blk_integrity_exchg bix;
        struct bio_vec *bv;
        struct bio_integrity_payload *bip = bio_integrity(bio);
-       sector_t sector;
-       unsigned int sectors, ret = 0, i;
+       sector_t seed;
+       unsigned int intervals, ret = 0, i;
        void *prot_buf = page_address(bip->bip_vec->bv_page) +
                bip->bip_vec->bv_offset;
if (operate) 
-               sector = bio->bi_iter.bi_sector;
+               seed = bio->bi_iter.bi_sector;
        else
-               sector = bip->bip_iter.bi_sector;
+               seed = bip->bip_iter.bi_sector;
bix.disk_name = bio->bi_bdev->bd_disk->disk_name; 
-       bix.sector_size = bi->sector_size;
+       bix.interval = bi->interval;
bio_for_each_segment_all(bv, bio, i) { 
                void *kaddr = kmap_atomic(bv->bv_page);
                bix.data_buf = kaddr + bv->bv_offset;
                bix.data_size = bv->bv_len;
                bix.prot_buf = prot_buf;
-               bix.sector = sector;
+               bix.seed = seed;
if (operate) 
                        bi->generate_fn(&bix);
@@ -257,9 +253,9 @@ static int bio_integrity_generate_verify(struct bio *bio, 
int operate)
                        }
                }
- sectors = bv->bv_len / bi->sector_size; 
-               sector += sectors;
-               prot_buf += sectors * bi->tuple_size;
+               intervals = bv->bv_len / bi->interval;
+               seed += intervals;
+               prot_buf += intervals * bi->tuple_size;
kunmap_atomic(kaddr); 
        }
@@ -300,17 +296,17 @@ int bio_integrity_prep(struct bio *bio)
        unsigned long start, end;
        unsigned int len, nr_pages;
        unsigned int bytes, offset, i;
-       unsigned int sectors;
+       unsigned int intervals;
bi = bdev_get_integrity(bio->bi_bdev); 
        q = bdev_get_queue(bio->bi_bdev);
        BUG_ON(bi == NULL);
        BUG_ON(bio_integrity(bio));
- sectors = bio_integrity_hw_sectors(bi, bio_sectors(bio)); 
+       intervals = bio_integrity_intervals(bi, bio_sectors(bio));
/* Allocate kernel buffer for protection data */ 
-       len = sectors * bi->tuple_size;
+       len = intervals * bi->tuple_size;
        buf = kmalloc(len, GFP_NOIO | q->bounce_gfp);
        if (unlikely(buf == NULL)) {
                printk(KERN_ERR "could not allocate integrity buffer\n");
diff --git a/block/blk-integrity.c b/block/blk-integrity.c
index 7ac17160ab69..3760d0aeed92 100644
--- a/block/blk-integrity.c
+++ b/block/blk-integrity.c
@@ -154,10 +154,10 @@ int blk_integrity_compare(struct gendisk *gd1, struct 
gendisk *gd2)
        if (!b1 || !b2)
                return -1;
- if (b1->sector_size != b2->sector_size) { 
-               printk(KERN_ERR "%s: %s/%s sector sz %u != %u\n", __func__,
-                      gd1->disk_name, gd2->disk_name,
-                      b1->sector_size, b2->sector_size);
+       if (b1->interval != b2->interval) {
+               printk(KERN_ERR "%s: %s/%s protection interval %u != %u\n",
+                      __func__, gd1->disk_name, gd2->disk_name,
+                      b1->interval, b2->interval);
                return -1;
        }
@@ -407,7 +407,7 @@ int blk_integrity_register(struct gendisk *disk, struct blk_integrity *template) 
                kobject_uevent(&bi->kobj, KOBJ_ADD);
bi->flags |= INTEGRITY_FLAG_READ | INTEGRITY_FLAG_WRITE; 
-               bi->sector_size = queue_logical_block_size(disk->queue);
+               bi->interval = queue_logical_block_size(disk->queue);
                disk->integrity = bi;
        } else
                bi = disk->integrity;
diff --git a/drivers/scsi/sd_dif.c b/drivers/scsi/sd_dif.c
index 38a7778631be..1600270a46e5 100644
--- a/drivers/scsi/sd_dif.c
+++ b/drivers/scsi/sd_dif.c
@@ -57,16 +57,16 @@ static void sd_dif_type1_generate(struct 
blk_integrity_exchg *bix, csum_fn *fn)
  {
        void *buf = bix->data_buf;
        struct sd_dif_tuple *sdt = bix->prot_buf;
-       sector_t sector = bix->sector;
+       sector_t seed = bix->seed;
        unsigned int i;
- for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) { 
-               sdt->guard_tag = fn(buf, bix->sector_size);
-               sdt->ref_tag = cpu_to_be32(sector & 0xffffffff);
+       for (i = 0 ; i < bix->data_size ; i += bix->interval, sdt++) {
+               sdt->guard_tag = fn(buf, bix->interval);
+               sdt->ref_tag = cpu_to_be32(seed & 0xffffffff);
                sdt->app_tag = 0;
- buf += bix->sector_size; 
-               sector++;
+               buf += bix->interval;
+               seed++;
        }
  }
@@ -84,35 +84,35 @@ static int sd_dif_type1_verify(struct blk_integrity_exchg *bix, csum_fn *fn) 
  {
        void *buf = bix->data_buf;
        struct sd_dif_tuple *sdt = bix->prot_buf;
-       sector_t sector = bix->sector;
+       sector_t seed = bix->seed;
        unsigned int i;
        __u16 csum;
- for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) { 
+       for (i = 0 ; i < bix->data_size ; i += bix->interval, sdt++) {
                /* Unwritten sectors */
                if (sdt->app_tag == 0xffff)
                        return 0;
- if (be32_to_cpu(sdt->ref_tag) != (sector & 0xffffffff)) { 
+               if (be32_to_cpu(sdt->ref_tag) != (seed & 0xffffffff)) {
                        printk(KERN_ERR
                               "%s: ref tag error on sector %lu (rcvd %u)\n",
-                              bix->disk_name, (unsigned long)sector,
+                              bix->disk_name, (unsigned long)seed,
                               be32_to_cpu(sdt->ref_tag));
                        return -EIO;
                }
- csum = fn(buf, bix->sector_size); 
+               csum = fn(buf, bix->interval);
if (sdt->guard_tag != csum) { 
                        printk(KERN_ERR "%s: guard tag error on sector %lu " \
                               "(rcvd %04x, data %04x)\n", bix->disk_name,
-                              (unsigned long)sector,
+                              (unsigned long)seed,
                               be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum));
                        return -EIO;
                }
- buf += bix->sector_size; 
-               sector++;
+               buf += bix->interval;
+               seed++;
        }
return 0; 
@@ -155,12 +155,12 @@ static void sd_dif_type3_generate(struct 
blk_integrity_exchg *bix, csum_fn *fn)
        struct sd_dif_tuple *sdt = bix->prot_buf;
        unsigned int i;
- for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) { 
-               sdt->guard_tag = fn(buf, bix->sector_size);
+       for (i = 0 ; i < bix->data_size ; i += bix->interval, sdt++) {
+               sdt->guard_tag = fn(buf, bix->interval);
                sdt->ref_tag = 0;
                sdt->app_tag = 0;
- buf += bix->sector_size; 
+               buf += bix->interval;
        }
  }
@@ -178,27 +178,27 @@ static int sd_dif_type3_verify(struct blk_integrity_exchg *bix, csum_fn *fn) 
  {
        void *buf = bix->data_buf;
        struct sd_dif_tuple *sdt = bix->prot_buf;
-       sector_t sector = bix->sector;
+       sector_t seed = bix->seed;
        unsigned int i;
        __u16 csum;
- for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) { 
+       for (i = 0 ; i < bix->data_size ; i += bix->interval, sdt++) {
                /* Unwritten sectors */
                if (sdt->app_tag == 0xffff && sdt->ref_tag == 0xffffffff)
                        return 0;
- csum = fn(buf, bix->sector_size); 
+               csum = fn(buf, bix->interval);
if (sdt->guard_tag != csum) { 
                        printk(KERN_ERR "%s: guard tag error on sector %lu " \
                               "(rcvd %04x, data %04x)\n", bix->disk_name,
-                              (unsigned long)sector,
+                              (unsigned long)seed,
                               be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum));
                        return -EIO;
                }
- buf += bix->sector_size; 
-               sector++;
+               buf += bix->interval;
+               seed++;
        }
return 0; 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index ce42891dc386..b4fa1de92d29 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1434,9 +1434,9 @@ static inline uint64_t rq_io_start_time_ns(struct request 
*req)
  struct blk_integrity_exchg {
        void                    *prot_buf;
        void                    *data_buf;
-       sector_t                sector;
+       sector_t                seed;
        unsigned int            data_size;
-       unsigned short          sector_size;
+       unsigned short          interval;
        const char              *disk_name;
  };
@@ -1449,7 +1449,7 @@ struct blk_integrity { unsigned short flags; 
        unsigned short          tuple_size;
-       unsigned short          sector_size;
+       unsigned short          interval;
        unsigned short          tag_size;
const char *name; 

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