null_blk: allow byte aligned memory offsets

Allowing byte aligned memory provides a nice testing ground for
direct-io.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Tested-by: Hans Holmberg <hans.holmberg@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Keith Busch 2025-11-05 17:54:47 -08:00 committed by Jens Axboe
parent 262a3dd04e
commit 3451cf34f5
2 changed files with 25 additions and 22 deletions

View File

@ -1130,25 +1130,27 @@ static int null_make_cache_space(struct nullb *nullb, unsigned long n)
} }
static blk_status_t copy_to_nullb(struct nullb *nullb, void *source, static blk_status_t copy_to_nullb(struct nullb *nullb, void *source,
sector_t sector, size_t n, bool is_fua) loff_t pos, size_t n, bool is_fua)
{ {
size_t temp, count = 0; size_t temp, count = 0;
unsigned int offset;
struct nullb_page *t_page; struct nullb_page *t_page;
sector_t sector;
while (count < n) { while (count < n) {
temp = min_t(size_t, nullb->dev->blocksize, n - count); temp = min3(nullb->dev->blocksize, n - count,
PAGE_SIZE - offset_in_page(pos));
sector = pos >> SECTOR_SHIFT;
if (null_cache_active(nullb) && !is_fua) if (null_cache_active(nullb) && !is_fua)
null_make_cache_space(nullb, PAGE_SIZE); null_make_cache_space(nullb, PAGE_SIZE);
offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
t_page = null_insert_page(nullb, sector, t_page = null_insert_page(nullb, sector,
!null_cache_active(nullb) || is_fua); !null_cache_active(nullb) || is_fua);
if (!t_page) if (!t_page)
return BLK_STS_NOSPC; return BLK_STS_NOSPC;
memcpy_to_page(t_page->page, offset, source + count, temp); memcpy_to_page(t_page->page, offset_in_page(pos),
source + count, temp);
__set_bit(sector & SECTOR_MASK, t_page->bitmap); __set_bit(sector & SECTOR_MASK, t_page->bitmap);
@ -1156,33 +1158,33 @@ static blk_status_t copy_to_nullb(struct nullb *nullb, void *source,
null_free_sector(nullb, sector, true); null_free_sector(nullb, sector, true);
count += temp; count += temp;
sector += temp >> SECTOR_SHIFT; pos += temp;
} }
return BLK_STS_OK; return BLK_STS_OK;
} }
static void copy_from_nullb(struct nullb *nullb, void *dest, sector_t sector, static void copy_from_nullb(struct nullb *nullb, void *dest, loff_t pos,
size_t n) size_t n)
{ {
size_t temp, count = 0; size_t temp, count = 0;
unsigned int offset;
struct nullb_page *t_page; struct nullb_page *t_page;
sector_t sector;
while (count < n) { while (count < n) {
temp = min_t(size_t, nullb->dev->blocksize, n - count); temp = min3(nullb->dev->blocksize, n - count,
PAGE_SIZE - offset_in_page(pos));
sector = pos >> SECTOR_SHIFT;
offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
t_page = null_lookup_page(nullb, sector, false, t_page = null_lookup_page(nullb, sector, false,
!null_cache_active(nullb)); !null_cache_active(nullb));
if (t_page) if (t_page)
memcpy_from_page(dest + count, t_page->page, offset, memcpy_from_page(dest + count, t_page->page,
temp); offset_in_page(pos), temp);
else else
memset(dest + count, 0, temp); memset(dest + count, 0, temp);
count += temp; count += temp;
sector += temp >> SECTOR_SHIFT; pos += temp;
} }
} }
@ -1228,7 +1230,7 @@ static blk_status_t null_handle_flush(struct nullb *nullb)
} }
static blk_status_t null_transfer(struct nullb *nullb, struct page *page, static blk_status_t null_transfer(struct nullb *nullb, struct page *page,
unsigned int len, unsigned int off, bool is_write, sector_t sector, unsigned int len, unsigned int off, bool is_write, loff_t pos,
bool is_fua) bool is_fua)
{ {
struct nullb_device *dev = nullb->dev; struct nullb_device *dev = nullb->dev;
@ -1240,10 +1242,10 @@ static blk_status_t null_transfer(struct nullb *nullb, struct page *page,
if (!is_write) { if (!is_write) {
if (dev->zoned) if (dev->zoned)
valid_len = null_zone_valid_read_len(nullb, valid_len = null_zone_valid_read_len(nullb,
sector, len); pos >> SECTOR_SHIFT, len);
if (valid_len) { if (valid_len) {
copy_from_nullb(nullb, p, sector, valid_len); copy_from_nullb(nullb, p, pos, valid_len);
off += valid_len; off += valid_len;
len -= valid_len; len -= valid_len;
} }
@ -1253,7 +1255,7 @@ static blk_status_t null_transfer(struct nullb *nullb, struct page *page,
flush_dcache_page(page); flush_dcache_page(page);
} else { } else {
flush_dcache_page(page); flush_dcache_page(page);
err = copy_to_nullb(nullb, p, sector, len, is_fua); err = copy_to_nullb(nullb, p, pos, len, is_fua);
} }
kunmap_local(p); kunmap_local(p);
@ -1271,7 +1273,7 @@ static blk_status_t null_handle_data_transfer(struct nullb_cmd *cmd,
struct nullb *nullb = cmd->nq->dev->nullb; struct nullb *nullb = cmd->nq->dev->nullb;
blk_status_t err = BLK_STS_OK; blk_status_t err = BLK_STS_OK;
unsigned int len; unsigned int len;
sector_t sector = blk_rq_pos(rq); loff_t pos = blk_rq_pos(rq) << SECTOR_SHIFT;
unsigned int max_bytes = nr_sectors << SECTOR_SHIFT; unsigned int max_bytes = nr_sectors << SECTOR_SHIFT;
unsigned int transferred_bytes = 0; unsigned int transferred_bytes = 0;
struct req_iterator iter; struct req_iterator iter;
@ -1283,11 +1285,11 @@ static blk_status_t null_handle_data_transfer(struct nullb_cmd *cmd,
if (transferred_bytes + len > max_bytes) if (transferred_bytes + len > max_bytes)
len = max_bytes - transferred_bytes; len = max_bytes - transferred_bytes;
err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset, err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset,
op_is_write(req_op(rq)), sector, op_is_write(req_op(rq)), pos,
rq->cmd_flags & REQ_FUA); rq->cmd_flags & REQ_FUA);
if (err) if (err)
break; break;
sector += len >> SECTOR_SHIFT; pos += len;
transferred_bytes += len; transferred_bytes += len;
if (transferred_bytes >= max_bytes) if (transferred_bytes >= max_bytes)
break; break;
@ -1944,6 +1946,7 @@ static int null_add_dev(struct nullb_device *dev)
.logical_block_size = dev->blocksize, .logical_block_size = dev->blocksize,
.physical_block_size = dev->blocksize, .physical_block_size = dev->blocksize,
.max_hw_sectors = dev->max_sectors, .max_hw_sectors = dev->max_sectors,
.dma_alignment = 1,
}; };
struct nullb *nullb; struct nullb *nullb;

View File

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