Commit dd85b492 authored by Ajay Joshi's avatar Ajay Joshi Committed by Jens Axboe
Browse files

null_blk: return fixed zoned reads > write pointer 



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: default avatarAjay Joshi <ajay.joshi@wdc.com>
Reviewed-by: default avatarDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: default avatarMatias Bjørling <matias.bjorling@wdc.com>
Signed-off-by: default avatarChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 45919fbf

drivers/block/null_blk.h

+8 −0
Original line number Diff line number Diff line
@@ -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 */

drivers/block/null_blk_main.c

+25 −1
Original line number Diff line number Diff line
@@ -1022,6 +1022,16 @@ next: 
	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);

drivers/block/null_blk_zoned.c

+19 −2
Original line number Diff line number Diff line
@@ -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)) {

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