On Mon, 2021-04-26 at 00:14 +0100, David Howells wrote: > Hi Al, > > I think this patch should include all the fixes necessary. I could merge > it in, but I think it might be better to tag it on the end as an additional > patch. > > David > --- > iov_iter: Four fixes for ITER_XARRAY > > Fix four things[1] in the patch that adds ITER_XARRAY[2]: > > (1) Remove the address_space struct predeclaration. This is a holdover > from when it was ITER_MAPPING. > > (2) Fix _copy_mc_to_iter() so that the xarray segment updates count and > iov_offset in the iterator before returning. > > (3) Fix iov_iter_alignment() to not loop in the xarray case. Because the > middle pages are all whole pages, only the end pages need be > considered - and this can be reduced to just looking at the start > position in the xarray and the iteration size. > > (4) Fix iov_iter_advance() to limit the size of the advance to no more > than the remaining iteration size. > > Reported-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> > Signed-off-by: David Howells <dhowells@xxxxxxxxxx> > Link: https://lore.kernel.org/r/YIVrJT8GwLI0Wlgx@xxxxxxxxxxxxxxxxxxxxx [1] > Link: https://lore.kernel.org/r/161918448151.3145707.11541538916600921083.stgit@xxxxxxxxxxxxxxxxxxxxxx [2] > --- > include/linux/uio.h | 1 - > lib/iov_iter.c | 5 +++++ > 2 files changed, 5 insertions(+), 1 deletion(-) > > diff --git a/include/linux/uio.h b/include/linux/uio.h > index 5f5ffc45d4aa..d3ec87706d75 100644 > --- a/include/linux/uio.h > +++ b/include/linux/uio.h > @@ -10,7 +10,6 @@ > #include <uapi/linux/uio.h> > > > > > struct page; > -struct address_space; > struct pipe_inode_info; > > > > > struct kvec { > diff --git a/lib/iov_iter.c b/lib/iov_iter.c > index 44fa726a8323..61228a6c69f8 100644 > --- a/lib/iov_iter.c > +++ b/lib/iov_iter.c > @@ -791,6 +791,8 @@ size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) > curr_addr = (unsigned long) from; > bytes = curr_addr - s_addr - rem; > rcu_read_unlock(); > + i->iov_offset += bytes; > + i->count -= bytes; > return bytes; > } > }) > @@ -1147,6 +1149,7 @@ void iov_iter_advance(struct iov_iter *i, size_t size) > return; > } > if (unlikely(iov_iter_is_xarray(i))) { > + size = min(size, i->count); > i->iov_offset += size; > i->count -= size; > return; > @@ -1346,6 +1349,8 @@ unsigned long iov_iter_alignment(const struct iov_iter *i) > return size | i->iov_offset; > return size; > } > + if (unlikely(iov_iter_is_xarray(i))) > + return (i->xarray_start + i->iov_offset) | i->count; > iterate_all_kinds(i, size, v, > (res |= (unsigned long)v.iov_base | v.iov_len, 0), > res |= v.bv_offset | v.bv_len, > I did a test run with your v7 pile, this patch, and my ceph fscache rework patches and it did fine. You can add: Tested-by: Jeff Layton <jlayton@xxxxxxxxxx>
