Re: [RFC PATCH 1/3] filemap: convert page_endio to folio_endio
From: Christoph Hellwig <hch@infradead.org>
Date: 2023-03-16 15:24:25
Also in:
linux-fsdevel, linux-mm, lkml
On Thu, Mar 16, 2023 at 11:04:54AM +0100, Pankaj Raghav wrote:
It looks like this endio function is called when alloc_page is used (for partial IO) to trigger writeback from the user space `echo "idle" > /sys/block/zram0/writeback`.
Yes.
I don't understand when you say the harm might not be horrible if we don't call folio_endio here. Do you think it is just safe to remove the call to folio_endio function?
I suspect so. It doesn't seem like the involved pages are ever locked or have the writeback set, so it should be fine.
+ while ((folio = readahead_folio(rac))) {
+ folio_clear_uptodate(folio);
+ folio_set_error(folio);
+ folio_unlock(folio);
+ }
+ return;
+ }
+
+ while ((folio = readahead_folio(rac))) {
+ folio_mark_uptodate(folio);
+ folio_unlock(folio);
}
}Looks good.
quoted hunk ↗ jump to hunk
@@ -59,7 +59,8 @@ static void mpage_end_io(struct bio *bio)static struct bio *mpage_bio_submit(struct bio *bio) { - bio->bi_end_io = mpage_end_io; + bio->bi_end_io = (op_is_write(bio_op(bio))) ? mpage_write_end_io : + mpage_read_end_io; guard_bio_eod(bio); submit_bio(bio); return NULL; And mpage_{write,read}_end_io will iterate over the folio and call the respective functions.
Yes, although I'd do it with a good old if/else and with less braces. It might make sense to split mpage_bio_submit as well, though.