David Reaver wrote: > kmap_atomic() is deprecated and should be replaced with kmap_local_page() > [1][2]. kmap_local_page() is faster in kernels with HIGHMEM enabled, can > take page faults, and allows preemption.
Thanks for taking these on! It is good to see some progress here. > > According to [2], this replacement is safe as long as the code between > kmap_atomic() and kunmap_atomic() does not implicitly depend on disabling > page faults or preemption. In this patch, the only thing happening between > mapping and unmapping the page is a memcpy, and I don't suspect it depends > on disabling page faults or preemption. > > [1] https://lwn.net/Articles/836144/ > [2] https://docs.kernel.org/mm/highmem.html#temporary-virtual-mappings > > Signed-off-by: David Reaver <m...@davidreaver.com> > --- > drivers/char/virtio_console.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c > index c62b208b42f1..24442485e73e 100644 > --- a/drivers/char/virtio_console.c > +++ b/drivers/char/virtio_console.c > @@ -883,9 +883,9 @@ static int pipe_to_sg(struct pipe_inode_info *pipe, > struct pipe_buffer *buf, > if (len + offset > PAGE_SIZE) > len = PAGE_SIZE - offset; > > - src = kmap_atomic(buf->page); > + src = kmap_local_page(buf->page); > memcpy(page_address(page) + offset, src + buf->offset, len); > - kunmap_atomic(src); > + kunmap_local(src); memcpy_to_page() Ira [snip]
