On Wed, Aug 08, 2012 at 07:56:10PM -0700, Kent Overstreet wrote: > > So, bio_clone() loses its function comment. Also, does it even make > > sense to call bio_clone() from fs_bio_set? > > I'll re add the function comment if you want, just for a single line > wrapper I don't know if it's worth the cost - comments get out of date, > and they're more stuff to wade through. People actually look at docbook generated docs. I don't know why but they do. It's a utility function at block layer. Please just add the comment. > > Let's say it's so, then > > what's the difference from using _kmalloc variant? > > bio_kmalloc() fails if nr_iovecs > 1024, bio_alloc_bioset() fails if > nr_iovecs > 256 > > and bio_alloc_bioset() is mempool backed, bio_kmalloc() is not. > > AFAICT that's it. So, the thing is being mempool backed doesn't mean anything if multiple layers use the pool. I *suspect* fs_bio_set is supposed to be used by fs layer - ie. where bios originate. The reason why I wondered about bio_clone() is that bio_clone() is almost always used from stacking drivers and stacking driver tapping into fs reserve is buggy. So, I'm wondering whether cloning from fs_bio_set should be supported at all. Thanks. -- tejun -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
