From: Ajay Joshi <[email protected]> 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 <[email protected]> Reviewed-by: Damien Le Moal <[email protected]> Reviewed-by: Matias Bjørling <[email protected]> Signed-off-by: Chaitanya Kulkarni <[email protected]> --- Hi, This patch is originally posted in July :- https://www.spinics.net/lists/linux-block/msg42403.html. Resending this patch based on latest linux-block tree for-next branch. -Chaitanya --- drivers/block/null_blk.h | 8 ++++++++ drivers/block/null_blk_main.c | 26 +++++++++++++++++++++++++- drivers/block/null_blk_zoned.c | 21 +++++++++++++++++++-- 3 files changed, 52 insertions(+), 3 deletions(-) diff --git a/drivers/block/null_blk.h b/drivers/block/null_blk.h index a235c45e22a7..93c2a3d403da 100644 --- a/drivers/block/null_blk.h +++ b/drivers/block/null_blk.h @@ -96,6 +96,8 @@ int null_zone_report(struct gendisk *disk, sector_t sector, blk_status_t null_handle_zoned(struct nullb_cmd *cmd, enum req_opf op, sector_t sector, sector_t nr_sectors); +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) { @@ -115,5 +117,11 @@ static inline blk_status_t null_handle_zoned(struct nullb_cmd *cmd, { return BLK_STS_NOTSUPP; } +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 f5e0dffb4624..ea7a4d6b7848 100644 --- a/drivers/block/null_blk_main.c +++ b/drivers/block/null_blk_main.c @@ -1022,6 +1022,16 @@ 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; @@ -1062,10 +1072,24 @@ static int null_transfer(struct nullb *nullb, struct page *page, unsigned int len, unsigned int off, bool is_write, sector_t sector, bool is_fua) { + struct nullb_device *dev = nullb->dev; + unsigned int valid_len = len; int err = 0; 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 eabc116832a7..e020f17dac9f 100644 --- a/drivers/block/null_blk_zoned.c +++ b/drivers/block/null_blk_zoned.c @@ -84,6 +84,24 @@ 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; +} + static blk_status_t null_zone_write(struct nullb_cmd *cmd, sector_t sector, unsigned int nr_sectors) { @@ -121,8 +139,7 @@ static blk_status_t null_zone_write(struct nullb_cmd *cmd, sector_t sector, static blk_status_t null_zone_reset(struct nullb_cmd *cmd, sector_t sector) { struct nullb_device *dev = cmd->nq->dev; - unsigned int zno = null_zone_no(dev, sector); - struct blk_zone *zone = &dev->zones[zno]; + struct blk_zone *zone = &dev->zones[null_zone_no(dev, sector)]; size_t i; switch (req_op(cmd->rq)) { -- 2.22.1
