| Message ID | 20170808084548.18963-10-ming.lei@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
> + * The hacking way of using bvec table as page pointer array is safe > + * even after multipage bvec is introduced because that space can be > + * thought as unused by bio_add_page(). I'm not sure what value this comment adds. Note that once we have multi-page biovecs this could should change to take advantage of multipage biovecs, so adding a comment before that doesn't seem too helpful.
On Thu, Aug 10, 2017 at 04:28:05AM -0700, Christoph Hellwig wrote: > > + * The hacking way of using bvec table as page pointer array is safe > > + * even after multipage bvec is introduced because that space can be > > + * thought as unused by bio_add_page(). > > I'm not sure what value this comment adds. > > Note that once we have multi-page biovecs this could should change > to take advantage of multipage biovecs, so adding a comment before > that doesn't seem too helpful. As mentioned in comment on patch 8, bio_alloc_pages() should be move to bcache.
diff --git a/block/bio.c b/block/bio.c index 826b5d173416..28697e3c8ce3 100644 --- a/block/bio.c +++ b/block/bio.c @@ -875,6 +875,10 @@ EXPORT_SYMBOL(bio_add_page); * * Pins as many pages from *iter and appends them to @bio's bvec array. The * pages will have to be released using put_page() when done. + * + * The hacking way of using bvec table as page pointer array is safe + * even after multipage bvec is introduced because that space can be + * thought as unused by bio_add_page(). */ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) {
bio_iov_iter_get_pages() used unused bvec spaces for storing page pointer array temporarily, and this patch comments on this usage wrt. multipage bvec support. Signed-off-by: Ming Lei <ming.lei@redhat.com> --- block/bio.c | 4 ++++ 1 file changed, 4 insertions(+)