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null_blk: fix zone read length beyond write pointer 

Fix up the divisor calculating the number of zone sectors being read and
handle a read that straddles the zone write pointer. The length is
rounded up a sector boundary, so be sure to truncate any excess bytes
off to avoid copying past the data segment.

Fixes: 3451cf34f5 ("null_blk: allow byte aligned memory offsets")
Signed-off-by: Keith Busch <kbusch@kernel.org>
Tested-by: Bart van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Keith Busch 2025-11-12 08:42:18 -08:00 committed by Jens Axboe
parent 6d7e3870af
commit 3749ea4dee
2 changed files with 5 additions and 2 deletions
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5
drivers/block/null_blk/main.c
View File

@ -1240,9 +1240,12 @@ static blk_status_t null_transfer(struct nullb *nullb, struct page *page,
p = kmap_local_page(page) + off;
if (!is_write) {
if (dev->zoned)
if (dev->zoned) {
valid_len = null_zone_valid_read_len(nullb,
pos >> SECTOR_SHIFT, len);
if (valid_len && valid_len != len)
valid_len -= pos & (SECTOR_SIZE - 1);
}
if (valid_len) {
copy_from_nullb(nullb, p, pos, valid_len);

2
drivers/block/null_blk/zoned.c
View File

@ -242,7 +242,7 @@ size_t null_zone_valid_read_len(struct nullb *nullb,
{
struct nullb_device *dev = nullb->dev;
struct nullb_zone *zone = &dev->zones[null_zone_no(dev, sector)];
unsigned int nr_sectors = DIV_ROUND_UP(len, SECTOR_SHIFT);
unsigned int nr_sectors = DIV_ROUND_UP(len, SECTOR_SIZE);
/* Read must be below the write pointer position */
if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL ||