A zoned block device maintains a write pointer within a zone, and
reads beyond the write pointer are undefined.
Fill data buffer returned above the write pointer with 0xFF.
Signed-off-by: Ajay Joshi <ajay.jo...@wdc.com>
Reviewed-by: Damien Le Moal <damien.lem...@wdc.com>
Reviewed-by: Matias Bjørling <matias.bjorl...@wdc.com>
---
drivers/block/null_blk.h | 7 +++++++
drivers/block/null_blk_main.c | 26 +++++++++++++++++++++++++-
drivers/block/null_blk_zoned.c | 18 ++++++++++++++++++
3 files changed, 50 insertions(+), 1 deletion(-)
diff --git a/drivers/block/null_blk.h b/drivers/block/null_blk.h
index 34b22d6523ba..fa82c4d96c8a 100644
--- a/drivers/block/null_blk.h
+++ b/drivers/block/null_blk.h
@@ -94,6 +94,8 @@ int null_zone_report(struct gendisk *disk, sector_t sector,
void null_zone_write(struct nullb_cmd *cmd, sector_t sector,
unsigned int nr_sectors);
void null_zone_reset(struct nullb_cmd *cmd, sector_t sector);
+size_t null_zone_valid_read_len(struct nullb *nullb,
+ sector_t sector, unsigned int len);
#else
static inline int null_zone_init(struct nullb_device *dev)
{
@@ -112,5 +114,10 @@ static inline void null_zone_write(struct nullb_cmd *cmd,
sector_t sector,
{
}
static inline void null_zone_reset(struct nullb_cmd *cmd, sector_t sector) {}
+static inline size_t null_zone_valid_read_len(struct nullb *nullb,
+ sector_t sector, unsigned int len)
+{
+ return len;
+}
#endif /* CONFIG_BLK_DEV_ZONED */
#endif /* __NULL_BLK_H */
diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
index 99328ded60d1..ce66f4e6268a 100644
--- a/drivers/block/null_blk_main.c
+++ b/drivers/block/null_blk_main.c
@@ -996,6 +996,16 @@ static int copy_from_nullb(struct nullb *nullb, struct
page *dest,
return 0;
}
+static void nullb_fill_pattern(struct nullb *nullb,
+ struct page *page, unsigned int len, unsigned int off)
+{
+ void *dst;
+
+ dst = kmap_atomic(page);
+ memset(dst + off, 0xFF, len);
+ kunmap_atomic(dst);
+}
+
static void null_handle_discard(struct nullb *nullb, sector_t sector, size_t n)
{
size_t temp;
@@ -1037,9 +1047,23 @@ static int null_transfer(struct nullb *nullb, struct
page *page,
bool is_fua)
{
int err = 0;
+ struct nullb_device *dev = nullb->dev;
+ unsigned int valid_len = len;
if (!is_write) {
- err = copy_from_nullb(nullb, page, off, sector, len);
+ if (dev->zoned)
+ valid_len = null_zone_valid_read_len(nullb,
+ sector, len);
+
+ if (valid_len) {
+ err = copy_from_nullb(nullb, page, off,
+ sector, valid_len);
+ off += valid_len;
+ len -= valid_len;
+ }
+
+ if (len)
+ nullb_fill_pattern(nullb, page, len, off);
flush_dcache_page(page);
} else {
flush_dcache_page(page);
diff --git a/drivers/block/null_blk_zoned.c b/drivers/block/null_blk_zoned.c
index fca0c97ff1aa..20a3c08e628c 100644
--- a/drivers/block/null_blk_zoned.c
+++ b/drivers/block/null_blk_zoned.c
@@ -85,6 +85,24 @@ int null_zone_report(struct gendisk *disk, sector_t sector,
return 0;
}
+size_t null_zone_valid_read_len(struct nullb *nullb,
+ sector_t sector, unsigned int len)
+{
+ struct nullb_device *dev = nullb->dev;
+ struct blk_zone *zone = &dev->zones[null_zone_no(dev, sector)];
+ unsigned int nr_sectors = len >> SECTOR_SHIFT;
+
+ /* Read must be below the write pointer position */
+ if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL ||
+ sector + nr_sectors <= zone->wp)
+ return len;
+
+ if (sector > zone->wp)
+ return 0;
+
+ return (zone->wp - sector) << SECTOR_SHIFT;
+}
+
void null_zone_write(struct nullb_cmd *cmd, sector_t sector,
unsigned int nr_sectors)
{
--
2.19.1
