diff options
| author | David Reaver <me@davidreaver.com> | 2025-01-08 19:59:02 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-01-10 16:12:38 +0100 |
| commit | 4cabaa0517a9c6157ef5e953825dcd1907ff4d69 (patch) | |
| tree | f70ccba163c68272a391da43f6bda39492be203a | |
| parent | a01f6287c244f35eeec11ca932d09061181eed8c (diff) | |
virtio: console: Replace deprecated kmap_atomic with kmap_local_page
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.
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 <me@davidreaver.com>
Reviewed-by: Amit Shah <amit@kernel.org>
Link: https://lore.kernel.org/r/20250109035904.168345-1-me@davidreaver.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/char/virtio_console.c | 4 |
1 files 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); sg_set_page(&(sgl->sg[sgl->n]), page, len, offset); } |