On 12/6/20 2:25 PM, Tom Yan wrote:
I think you misunderstood it. The goal of this patch is to split the
current situation into two chains (or one unchained bio + a series of
chained bio). The first one is an attempt/trial which makes sure that
the latter large bio chain can actually be handled (as per the
"command capability" of the device).
Oh, I think I do get what you're trying to do. And, in fact, I don't
argue with what you're trying to achieve.
What I would like to see, though, is keep the current bio_chain logic
intact (irrespective of your previous patch, which should actually be
part of this series), and just lift the first check out of the loop:
@@ -262,9 +262,14 @@ static int __blkdev_issue_write_zeroes(struct
block_device *bdev,
if (max_write_zeroes_sectors == 0)
return -EOPNOTSUPP;
-
+ new = bio_alloc(gfp_mask, 0);
+ bio_chain(bio, new);
+ if (submit_bio_wait(bio) == BLK_STS_NOTSUPP) {
+ bio_put(new);
+ return -ENOPNOTSUPP;
+ }
+ bio = new;
while (nr_sects) {
- bio = blk_next_bio(bio, 0, gfp_mask);
bio->bi_iter.bi_sector = sector;
bio_set_dev(bio, bdev);
bio->bi_opf = REQ_OP_WRITE_ZEROES;
@@ -279,6 +284,7 @@ static int __blkdev_issue_write_zeroes(struct
block_device *bdev,
bio->bi_iter.bi_size = nr_sects << 9;
nr_sects = 0;
}
+ bio = blk_next_bio(bio, 0, gfp_mask);
cond_resched();
}
(The error checking from submit_bio_wait() could be improved :-)
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@xxxxxxx +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
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