Commit Graph

11 Commits

Author SHA1 Message Date
Al Viro c7f3888ad7 switch iov_iter_get_pages() to passing maximal number of pages
... instead of maximal size.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-08-07 14:40:11 -04:00
Al Viro 62a8067a7f bio_vec-backed iov_iter
New variant of iov_iter - ITER_BVEC in iter->type, backed with
bio_vec array instead of iovec one.  Primitives taught to deal
with such beasts, __swap_write() switched to using that kind
of iov_iter.

Note that bio_vec is just a <page, offset, length> triple - there's
nothing block-specific about it.  I've left the definition where it
was, but took it from under ifdef CONFIG_BLOCK.

Next target: ->splice_write()...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-05-06 17:39:45 -04:00
Al Viro 81055e584f optimize copy_page_{to,from}_iter()
if we'd ended up in the end of a segment, jump to the
beginning of the next one (iov_offset = 0, iov++),
rather than having the next primitive deal with that.

Ought to be folded back...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-05-06 17:39:45 -04:00
Al Viro f0d1bec9d5 new helper: copy_page_from_iter()
parallel to copy_page_to_iter().  pipe_write() switched to it (and became
->write_iter()).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-05-06 17:39:42 -04:00
Al Viro 91f79c43d1 new helper: iov_iter_get_pages_alloc()
same as iov_iter_get_pages(), except that pages array is allocated
(kmalloc if possible, vmalloc if that fails) and left for caller to
free.  Lustre and NFS ->direct_IO() switched to it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-05-06 17:32:53 -04:00
Al Viro f67da30c1d new helper: iov_iter_npages()
counts the pages covered by iov_iter, up to given limit.
do_block_direct_io() and fuse_iter_npages() switched to
it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-05-06 17:32:52 -04:00
Al Viro 7b2c99d155 new helper: iov_iter_get_pages()
iov_iter_get_pages(iter, pages, maxsize, &start) grabs references pinning
the pages of up to maxsize of (contiguous) data from iter.  Returns the
amount of memory grabbed or -error.  In case of success, the requested
area begins at offset start in pages[0] and runs through pages[1], etc.
Less than requested amount might be returned - either because the contiguous
area in the beginning of iterator is smaller than requested, or because
the kernel failed to pin that many pages.

direct-io.c switched to using iov_iter_get_pages()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-05-06 17:32:50 -04:00
Al Viro 71d8e532b1 start adding the tag to iov_iter
For now, just use the same thing we pass to ->direct_IO() - it's all
iovec-based at the moment.  Pass it explicitly to iov_iter_init() and
account for kvec vs. iovec in there, by the same kludge NFS ->direct_IO()
uses.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-05-06 17:32:49 -04:00
Al Viro 886a391150 new primitive: iov_iter_alignment()
returns the value aligned as badly as the worst remaining segment
in iov_iter is.  Use instead of open-coded equivalents.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-05-06 17:32:47 -04:00
Al Viro e7c24607b5 kill iov_iter_copy_from_user()
all callers can use copy_page_from_iter() and it actually simplifies
them.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-05-06 17:32:42 -04:00
Al Viro 4f18cd317a take iov_iter stuff to mm/iov_iter.c
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-04-01 23:19:30 -04:00