From: NeilBrown <neilb@cse.unsw.edu.au>
For each resync request, we allocate a "r1_bio" which has a bio "master_bio"
attached that goes largely unused. We also allocate a read_bio which is
used. This patch removes the read_bio and just uses the master_bio instead.
This fixes a bug wherein bi_bdev of the master_bio wasn't being set, but was
being used.
We also introduce a new "sectors" field into the r1_bio as we can no-longer
rely in master_bio->bi_sectors.
---
drivers/md/raid1.c | 37 ++++++++++++++++++-------------------
include/linux/raid/raid1.h | 1 +
2 files changed, 19 insertions(+), 19 deletions(-)
diff -puN drivers/md/raid1.c~md-05-avoid-bio-allocation drivers/md/raid1.c
--- 25/drivers/md/raid1.c~md-05-avoid-bio-allocation 2004-02-05 22:06:03.000000000 -0800
+++ 25-akpm/drivers/md/raid1.c 2004-02-05 22:06:03.000000000 -0800
@@ -77,6 +77,9 @@ static void * r1buf_pool_alloc(int gfp_f
if (!bio)
goto out_free_r1_bio;
+ /*
+ * Allocate RESYNC_PAGES data pages for this iovec.
+ */
for (i = 0; i < RESYNC_PAGES; i++) {
page = alloc_page(gfp_flags);
if (unlikely(!page))
@@ -87,9 +90,6 @@ static void * r1buf_pool_alloc(int gfp_f
bio->bi_io_vec[i].bv_offset = 0;
}
- /*
- * Allocate a single data page for this iovec.
- */
bio->bi_vcnt = RESYNC_PAGES;
bio->bi_idx = 0;
bio->bi_size = RESYNC_BLOCK_SIZE;
@@ -122,8 +122,6 @@ static void r1buf_pool_free(void *__r1_b
__free_page(bio->bi_io_vec[i].bv_page);
bio->bi_io_vec[i].bv_page = NULL;
}
- if (atomic_read(&bio->bi_cnt) != 1)
- BUG();
bio_put(bio);
r1bio_pool_free(r1bio, conf->mddev);
}
@@ -249,7 +247,7 @@ static inline void update_head_pos(int d
conf_t *conf = mddev_to_conf(r1_bio->mddev);
conf->mirrors[disk].head_position =
- r1_bio->sector + (r1_bio->master_bio->bi_size >> 9);
+ r1_bio->sector + (r1_bio->sectors);
}
static int raid1_end_read_request(struct bio *bio, unsigned int bytes_done, int error)
@@ -507,6 +505,7 @@ static int make_request(request_queue_t
r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
r1_bio->master_bio = bio;
+ r1_bio->sectors = bio->bi_size >> 9;
r1_bio->mddev = mddev;
r1_bio->sector = bio->bi_sector;
@@ -799,7 +798,7 @@ static int end_sync_write(struct bio *bi
update_head_pos(mirror, r1_bio);
if (atomic_dec_and_test(&r1_bio->remaining)) {
- md_done_sync(mddev, r1_bio->master_bio->bi_size >> 9, uptodate);
+ md_done_sync(mddev, r1_bio->sectors, uptodate);
put_buf(r1_bio);
}
atomic_dec(&conf->mirrors[mirror].rdev->nr_pending);
@@ -829,7 +828,7 @@ static void sync_request_write(mddev_t *
" for block %llu\n",
bdevname(bio->bi_bdev,b),
(unsigned long long)r1_bio->sector);
- md_done_sync(mddev, r1_bio->master_bio->bi_size >> 9, 0);
+ md_done_sync(mddev, r1_bio->sectors, 0);
put_buf(r1_bio);
return;
}
@@ -874,7 +873,7 @@ static void sync_request_write(mddev_t *
}
if (atomic_dec_and_test(&r1_bio->remaining)) {
- md_done_sync(mddev, r1_bio->master_bio->bi_size >> 9, 1);
+ md_done_sync(mddev, r1_bio->sectors, 1);
put_buf(r1_bio);
}
}
@@ -966,7 +965,7 @@ static int sync_request(mddev_t *mddev,
conf_t *conf = mddev_to_conf(mddev);
mirror_info_t *mirror;
r1bio_t *r1_bio;
- struct bio *read_bio, *bio;
+ struct bio *bio;
sector_t max_sector, nr_sectors;
int disk, partial;
@@ -1035,18 +1034,18 @@ static int sync_request(mddev_t *mddev,
bio->bi_io_vec[bio->bi_vcnt-1].bv_len = partial;
- read_bio = bio_clone(r1_bio->master_bio, GFP_NOIO);
-
- read_bio->bi_sector = sector_nr + mirror->rdev->data_offset;
- read_bio->bi_bdev = mirror->rdev->bdev;
- read_bio->bi_end_io = end_sync_read;
- read_bio->bi_rw = READ;
- read_bio->bi_private = r1_bio;
- r1_bio->bios[r1_bio->read_disk] = read_bio;
+ bio->bi_sector = sector_nr + mirror->rdev->data_offset;
+ bio->bi_bdev = mirror->rdev->bdev;
+ bio->bi_end_io = end_sync_read;
+ bio->bi_rw = READ;
+ bio->bi_private = r1_bio;
+ bio_get(bio);
+ r1_bio->bios[r1_bio->read_disk] = bio;
+ r1_bio->sectors = nr_sectors;
md_sync_acct(mirror->rdev, nr_sectors);
- generic_make_request(read_bio);
+ generic_make_request(bio);
return nr_sectors;
}
diff -puN include/linux/raid/raid1.h~md-05-avoid-bio-allocation include/linux/raid/raid1.h
--- 25/include/linux/raid/raid1.h~md-05-avoid-bio-allocation 2004-02-05 22:06:03.000000000 -0800
+++ 25-akpm/include/linux/raid/raid1.h 2004-02-05 22:06:03.000000000 -0800
@@ -55,6 +55,7 @@ struct r1bio_s {
* used from IRQ handlers
*/
sector_t sector;
+ int sectors;
unsigned long state;
mddev_t *mddev;
/*
_