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dm bufio: support non-power-of-two block sizes

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Support block sizes that are not a power-of-two (but they must be a
multiple of 512b).  As always, a slab cache is used for allocations.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mikulas Patocka 2018-03-26 20:29:46 +02:00 committed by Mike Snitzer
parent 359dbf19ab
commit f51f2e0a7f
1 changed files with 39 additions and 25 deletions
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64
drivers/md/dm-bufio.c
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@ -56,12 +56,6 @@
*/
#define DM_BUFIO_INLINE_VECS 16
/*
* Don't try to use alloc_pages for blocks larger than this.
* For explanation, see alloc_buffer_data below.
*/
#define DM_BUFIO_BLOCK_SIZE_GFP_LIMIT (PAGE_SIZE << (MAX_ORDER - 1))
/*
* Align buffer writes to this boundary.
* Tests show that SSDs have the highest IOPS when using 4k writes.
@ -98,8 +92,7 @@ struct dm_bufio_client {
struct block_device *bdev;
unsigned block_size;
unsigned char sectors_per_block_bits;
unsigned char pages_per_block_bits;
s8 sectors_per_block_bits;
void (*alloc_callback)(struct dm_buffer *);
void (*write_callback)(struct dm_buffer *);
@ -375,11 +368,11 @@ static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask,
return kmem_cache_alloc(c->slab_cache, gfp_mask);
}
if (c->block_size <= DM_BUFIO_BLOCK_SIZE_GFP_LIMIT &&
if (c->block_size <= KMALLOC_MAX_SIZE &&
gfp_mask & __GFP_NORETRY) {
*data_mode = DATA_MODE_GET_FREE_PAGES;
return (void *)__get_free_pages(gfp_mask,
c->pages_per_block_bits);
c->sectors_per_block_bits - (PAGE_SHIFT - SECTOR_SHIFT));
}
*data_mode = DATA_MODE_VMALLOC;
@ -416,7 +409,8 @@ static void free_buffer_data(struct dm_bufio_client *c,
break;
case DATA_MODE_GET_FREE_PAGES:
free_pages((unsigned long)data, c->pages_per_block_bits);
free_pages((unsigned long)data,
c->sectors_per_block_bits - (PAGE_SHIFT - SECTOR_SHIFT));
break;
case DATA_MODE_VMALLOC:
@ -634,10 +628,14 @@ static void submit_io(struct dm_buffer *b, int rw, bio_end_io_t *end_io)
sector_t sector;
unsigned offset, end;
sector = (b->block << b->c->sectors_per_block_bits) + b->c->start;
if (likely(b->c->sectors_per_block_bits >= 0))
sector = b->block << b->c->sectors_per_block_bits;
else
sector = b->block * (b->c->block_size >> SECTOR_SHIFT);
sector += b->c->start;
if (rw != REQ_OP_WRITE) {
n_sectors = 1 << b->c->sectors_per_block_bits;
n_sectors = b->c->block_size >> SECTOR_SHIFT;
offset = 0;
} else {
if (b->c->write_callback)
@ -941,8 +939,11 @@ static void __get_memory_limit(struct dm_bufio_client *c,
}
}
buffers = dm_bufio_cache_size_per_client >>
(c->sectors_per_block_bits + SECTOR_SHIFT);
buffers = dm_bufio_cache_size_per_client;
if (likely(c->sectors_per_block_bits >= 0))
buffers >>= c->sectors_per_block_bits + SECTOR_SHIFT;
else
buffers /= c->block_size;
if (buffers < c->minimum_buffers)
buffers = c->minimum_buffers;
@ -1476,8 +1477,12 @@ EXPORT_SYMBOL_GPL(dm_bufio_get_block_size);
sector_t dm_bufio_get_device_size(struct dm_bufio_client *c)
{
return i_size_read(c->bdev->bd_inode) >>
(SECTOR_SHIFT + c->sectors_per_block_bits);
sector_t s = i_size_read(c->bdev->bd_inode) >> SECTOR_SHIFT;
if (likely(c->sectors_per_block_bits >= 0))
s >>= c->sectors_per_block_bits;
else
sector_div(s, c->block_size >> SECTOR_SHIFT);
return s;
}
EXPORT_SYMBOL_GPL(dm_bufio_get_device_size);
@ -1575,8 +1580,12 @@ static bool __try_evict_buffer(struct dm_buffer *b, gfp_t gfp)
static unsigned long get_retain_buffers(struct dm_bufio_client *c)
{
unsigned long retain_bytes = READ_ONCE(dm_bufio_retain_bytes);
return retain_bytes >> (c->sectors_per_block_bits + SECTOR_SHIFT);
unsigned long retain_bytes = READ_ONCE(dm_bufio_retain_bytes);
if (likely(c->sectors_per_block_bits >= 0))
retain_bytes >>= c->sectors_per_block_bits + SECTOR_SHIFT;
else
retain_bytes /= c->block_size;
return retain_bytes;
}
static unsigned long __scan(struct dm_bufio_client *c, unsigned long nr_to_scan,
@ -1642,8 +1651,11 @@ struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsign
unsigned i;
char slab_name[27];
BUG_ON(block_size < 1 << SECTOR_SHIFT ||
(block_size & (block_size - 1)));
if (!block_size || block_size & ((1 << SECTOR_SHIFT) - 1)) {
DMERR("%s: block size not specified or is not multiple of 512b", __func__);
r = -EINVAL;
goto bad_client;
}
c = kzalloc(sizeof(*c), GFP_KERNEL);
if (!c) {
@ -1654,9 +1666,10 @@ struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsign
c->bdev = bdev;
c->block_size = block_size;
c->sectors_per_block_bits = __ffs(block_size) - SECTOR_SHIFT;
c->pages_per_block_bits = (__ffs(block_size) >= PAGE_SHIFT) ?
__ffs(block_size) - PAGE_SHIFT : 0;
if (is_power_of_2(block_size))
c->sectors_per_block_bits = __ffs(block_size) - SECTOR_SHIFT;
else
c->sectors_per_block_bits = -1;
c->alloc_callback = alloc_callback;
c->write_callback = write_callback;
@ -1681,7 +1694,8 @@ struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsign
goto bad_dm_io;
}
if (block_size < PAGE_SIZE) {
if (block_size <= KMALLOC_MAX_SIZE &&
(block_size < PAGE_SIZE || !is_power_of_2(block_size))) {
snprintf(slab_name, sizeof slab_name, "dm_bufio_cache-%u", c->block_size);
c->slab_cache = kmem_cache_create(slab_name, c->block_size, ARCH_KMALLOC_MINALIGN,
SLAB_RECLAIM_ACCOUNT, NULL);