[dm-devel] [RFC PATCH 2/4] Add sector start offset to dm-bufio interface.
Milan Broz
gmazyland at gmail.com
Wed Jan 4 19:23:52 UTC 2017
From: Mikulas Patocka <mpatocka at redhat.com>
This patch adds possibility to set sector offset for dm-bufio client.
Signed-off-by: Mikulas Patocka <mpatocka at redhat.com>
Signed-off-by: Milan Broz <gmazyland at gmail.com>
---
drivers/md/dm-bufio.c | 51 ++++++++++++++++++++++++++++++++-------------------
drivers/md/dm-bufio.h | 7 +++++++
2 files changed, 39 insertions(+), 19 deletions(-)
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index 84d2f0e4c754..0105f9196ab3 100644
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -109,6 +109,8 @@ struct dm_bufio_client {
struct rb_root buffer_tree;
wait_queue_head_t free_buffer_wait;
+ sector_t start;
+
int async_write_error;
struct list_head client_list;
@@ -556,8 +558,8 @@ static void dmio_complete(unsigned long error, void *context)
b->bio.bi_end_io(&b->bio);
}
-static void use_dmio(struct dm_buffer *b, int rw, sector_t block,
- bio_end_io_t *end_io)
+static void use_dmio(struct dm_buffer *b, int rw, sector_t sector,
+ unsigned n_sectors, bio_end_io_t *end_io)
{
int r;
struct dm_io_request io_req = {
@@ -569,8 +571,8 @@ static void use_dmio(struct dm_buffer *b, int rw, sector_t block,
};
struct dm_io_region region = {
.bdev = b->c->bdev,
- .sector = block << b->c->sectors_per_block_bits,
- .count = b->c->block_size >> SECTOR_SHIFT,
+ .sector = sector,
+ .count = n_sectors,
};
if (b->data_mode != DATA_MODE_VMALLOC) {
@@ -605,14 +607,14 @@ static void inline_endio(struct bio *bio)
end_fn(bio);
}
-static void use_inline_bio(struct dm_buffer *b, int rw, sector_t block,
- bio_end_io_t *end_io)
+static void use_inline_bio(struct dm_buffer *b, int rw, sector_t sector,
+ unsigned n_sectors, bio_end_io_t *end_io)
{
char *ptr;
int len;
bio_init(&b->bio, b->bio_vec, DM_BUFIO_INLINE_VECS);
- b->bio.bi_iter.bi_sector = block << b->c->sectors_per_block_bits;
+ b->bio.bi_iter.bi_sector = sector;
b->bio.bi_bdev = b->c->bdev;
b->bio.bi_end_io = inline_endio;
/*
@@ -627,7 +629,7 @@ static void use_inline_bio(struct dm_buffer *b, int rw, sector_t block,
* If len < PAGE_SIZE the buffer doesn't cross page boundary.
*/
ptr = b->data;
- len = b->c->block_size;
+ len = n_sectors << SECTOR_SHIFT;
if (len >= PAGE_SIZE)
BUG_ON((unsigned long)ptr & (PAGE_SIZE - 1));
@@ -639,7 +641,7 @@ static void use_inline_bio(struct dm_buffer *b, int rw, sector_t block,
len < PAGE_SIZE ? len : PAGE_SIZE,
offset_in_page(ptr))) {
BUG_ON(b->c->block_size <= PAGE_SIZE);
- use_dmio(b, rw, block, end_io);
+ use_dmio(b, rw, sector, n_sectors, end_io);
return;
}
@@ -650,17 +652,22 @@ static void use_inline_bio(struct dm_buffer *b, int rw, sector_t block,
submit_bio(&b->bio);
}
-static void submit_io(struct dm_buffer *b, int rw, sector_t block,
- bio_end_io_t *end_io)
+static void submit_io(struct dm_buffer *b, int rw, bio_end_io_t *end_io)
{
+ unsigned n_sectors;
+ sector_t sector;
+
if (rw == WRITE && b->c->write_callback)
b->c->write_callback(b);
- if (b->c->block_size <= DM_BUFIO_INLINE_VECS * PAGE_SIZE &&
+ sector = (b->block << b->c->sectors_per_block_bits) + b->c->start;
+ n_sectors = 1 << b->c->sectors_per_block_bits;
+
+ if (n_sectors <= ((DM_BUFIO_INLINE_VECS * PAGE_SIZE) >> SECTOR_SHIFT) &&
b->data_mode != DATA_MODE_VMALLOC)
- use_inline_bio(b, rw, block, end_io);
+ use_inline_bio(b, rw, sector, n_sectors, end_io);
else
- use_dmio(b, rw, block, end_io);
+ use_dmio(b, rw, sector, n_sectors, end_io);
}
/*----------------------------------------------------------------
@@ -712,7 +719,7 @@ static void __write_dirty_buffer(struct dm_buffer *b,
wait_on_bit_lock_io(&b->state, B_WRITING, TASK_UNINTERRUPTIBLE);
if (!write_list)
- submit_io(b, WRITE, b->block, write_endio);
+ submit_io(b, WRITE, write_endio);
else
list_add_tail(&b->write_list, write_list);
}
@@ -725,7 +732,7 @@ static void __flush_write_list(struct list_head *write_list)
struct dm_buffer *b =
list_entry(write_list->next, struct dm_buffer, write_list);
list_del(&b->write_list);
- submit_io(b, WRITE, b->block, write_endio);
+ submit_io(b, WRITE, write_endio);
cond_resched();
}
blk_finish_plug(&plug);
@@ -1093,7 +1100,7 @@ static void *new_read(struct dm_bufio_client *c, sector_t block,
return NULL;
if (need_submit)
- submit_io(b, READ, b->block, read_endio);
+ submit_io(b, READ, read_endio);
wait_on_bit_io(&b->state, B_READING, TASK_UNINTERRUPTIBLE);
@@ -1163,7 +1170,7 @@ void dm_bufio_prefetch(struct dm_bufio_client *c,
dm_bufio_unlock(c);
if (need_submit)
- submit_io(b, READ, b->block, read_endio);
+ submit_io(b, READ, read_endio);
dm_bufio_release(b);
cond_resched();
@@ -1404,7 +1411,7 @@ void dm_bufio_release_move(struct dm_buffer *b, sector_t new_block)
old_block = b->block;
__unlink_buffer(b);
__link_buffer(b, new_block, b->list_mode);
- submit_io(b, WRITE, new_block, write_endio);
+ submit_io(b, WRITE, write_endio);
wait_on_bit_io(&b->state, B_WRITING,
TASK_UNINTERRUPTIBLE);
__unlink_buffer(b);
@@ -1761,6 +1768,12 @@ void dm_bufio_client_destroy(struct dm_bufio_client *c)
}
EXPORT_SYMBOL_GPL(dm_bufio_client_destroy);
+void dm_bufio_set_sector_offset(struct dm_bufio_client *c, sector_t start)
+{
+ c->start = start;
+}
+EXPORT_SYMBOL_GPL(dm_bufio_set_sector_offset);
+
static unsigned get_max_age_hz(void)
{
unsigned max_age = ACCESS_ONCE(dm_bufio_max_age);
diff --git a/drivers/md/dm-bufio.h b/drivers/md/dm-bufio.h
index c096779a7292..b6d8f53ec15b 100644
--- a/drivers/md/dm-bufio.h
+++ b/drivers/md/dm-bufio.h
@@ -32,6 +32,13 @@ dm_bufio_client_create(struct block_device *bdev, unsigned block_size,
void dm_bufio_client_destroy(struct dm_bufio_client *c);
/*
+ * Set the sector range.
+ * When this function is called, there must be no I/O in progress on the bufio
+ * client.
+ */
+void dm_bufio_set_sector_offset(struct dm_bufio_client *c, sector_t start);
+
+/*
* WARNING: to avoid deadlocks, these conditions are observed:
*
* - At most one thread can hold at most "reserved_buffers" simultaneously.
--
2.11.0
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