Sorry, meant to tag this as v2. But I missed the command line option as I am on
a new system and was working on getting aliases and other things setup to send
this mail.
-Stafford
On Sat, Oct 08, 2022 at 06:24:21AM +0100, Stafford Horne wrote:
> From: Jann Horn <[email protected]>
>
> Since commit 8782fb61cc848 ("mm: pagewalk: Fix race between unmap and page
> walker"), walk_page_range() on kernel ranges won't work anymore,
> walk_page_range_novma() must be used instead.
>
> Note: I don't have an openrisc development setup, so this is completely
> untested.
>
> Fixes: 8782fb61cc848 ("mm: pagewalk: Fix race between unmap and page walker")
> Signed-off-by: Jann Horn <[email protected]>
> Signed-off-by: Stafford Horne <[email protected]>
> ---
> Since v1:
> - Repost to include LKML.
> - Added my SOB
> - I tested this by booking this on the qemu virt platform and it works fine.
>
> arch/openrisc/kernel/dma.c | 16 ++++++++--------
> 1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/arch/openrisc/kernel/dma.c b/arch/openrisc/kernel/dma.c
> index a82b2caaa560..b3edbb33b621 100644
> --- a/arch/openrisc/kernel/dma.c
> +++ b/arch/openrisc/kernel/dma.c
> @@ -74,10 +74,10 @@ void *arch_dma_set_uncached(void *cpu_addr, size_t size)
> * We need to iterate through the pages, clearing the dcache for
> * them and setting the cache-inhibit bit.
> */
> - mmap_read_lock(&init_mm);
> - error = walk_page_range(&init_mm, va, va + size, &set_nocache_walk_ops,
> - NULL);
> - mmap_read_unlock(&init_mm);
> + mmap_write_lock(&init_mm);
> + error = walk_page_range_novma(&init_mm, va, va + size,
> + &set_nocache_walk_ops, NULL, NULL);
> + mmap_write_unlock(&init_mm);
>
> if (error)
> return ERR_PTR(error);
> @@ -88,11 +88,11 @@ void arch_dma_clear_uncached(void *cpu_addr, size_t size)
> {
> unsigned long va = (unsigned long)cpu_addr;
>
> - mmap_read_lock(&init_mm);
> + mmap_write_lock(&init_mm);
> /* walk_page_range shouldn't be able to fail here */
> - WARN_ON(walk_page_range(&init_mm, va, va + size,
> - &clear_nocache_walk_ops, NULL));
> - mmap_read_unlock(&init_mm);
> + WARN_ON(walk_page_range_novma(&init_mm, va, va + size,
> + &clear_nocache_walk_ops, NULL, NULL));
> + mmap_write_unlock(&init_mm);
> }
>
> void arch_sync_dma_for_device(phys_addr_t addr, size_t size,
> --
> 2.37.2
>