[PATCH v3 4/4] PM: submit bio in a sane way in cases without bio_chain

From: Ming Lin
Date: Thu Apr 23 2015 - 19:05:39 EST


From: Kent Overstreet <kent.overstreet@xxxxxxxxx>

Make bio submission in kernel/power/block_io.c to properly submit
bios also when bio_chain is not available. In that case, it's not
necessary to handle refcount with bio_get(), but it's saner to simply
call a predefined helper submit_bio_wait(). So call bio_get() only
when bio_chain is given.

Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: linux-pm@xxxxxxxxxxxxxxx
Acked-by: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>
Signed-off-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>
[dpark: add more description in commit message]
Signed-off-by: Dongsu Park <dongsu.park@xxxxxxxxxxxxxxxx>
Signed-off-by: Ming Lin <mlin@xxxxxxxxxx>
---
kernel/power/block_io.c | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/kernel/power/block_io.c b/kernel/power/block_io.c
index 9a58bc2..7206408 100644
--- a/kernel/power/block_io.c
+++ b/kernel/power/block_io.c
@@ -34,7 +34,6 @@ static int submit(int rw, struct block_device *bdev, sector_t sector,
bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
bio->bi_iter.bi_sector = sector;
bio->bi_bdev = bdev;
- bio->bi_end_io = end_swap_bio_read;

if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
printk(KERN_ERR "PM: Adding page to bio failed at %llu\n",
@@ -44,15 +43,29 @@ static int submit(int rw, struct block_device *bdev, sector_t sector,
}

lock_page(page);
- bio_get(bio);

if (bio_chain == NULL) {
- submit_bio(bio_rw, bio);
- wait_on_page_locked(page);
+ int err = submit_bio_wait(bio_rw, bio);
+
+ if (err) {
+ SetPageError(page);
+ ClearPageUptodate(page);
+ pr_alert("Read-error on swap-device (%u:%u:%llu)\n",
+ imajor(bio->bi_bdev->bd_inode),
+ iminor(bio->bi_bdev->bd_inode),
+ (unsigned long long)bio->bi_iter.bi_sector);
+ } else {
+ SetPageUptodate(page);
+ }
+
if (rw == READ)
- bio_set_pages_dirty(bio);
+ set_page_dirty_lock(page);
+ unlock_page(page);
bio_put(bio);
} else {
+ bio->bi_end_io = end_swap_bio_read;
+ bio_get(bio);
+
if (rw == READ)
get_page(page); /* These pages are freed later */
bio->bi_private = *bio_chain;
--
1.9.1

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