Re: [PATCH v6 03/19] openrisc: mm: remove unneeded early ioremap code

Mike Rapoport
2023-06-11T05:45:38Z

On Fri, Jun 09, 2023 at 03:55:12PM +0800, Baoquan He wrote:
> Under arch/openrisc, there isn't any place where ioremap() is called.
> It means that there isn't early ioremap handling needed in openrisc,
> So the early ioremap handling code in ioremap() of
> arch/openrisc/mm/ioremap.c is unnecessary and can be removed.
>
> And also remove the special handling in iounmap() since no page
> is got from fixmap pool along with early ioremap code removing
> in ioremap().
>
> Link: https://lore.kernel.org/linux-mm/YwxfxKrTUtAuejKQ@oscomms1/
> Signed-off-by: Baoquan He <bhe@redhat.com>
> Acked-by: Stafford Horne <shorne@gmail.com>
> Cc: Jonas Bonn <jonas@southpole.se>
> Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
> Cc: Stafford Horne <shorne@gmail.com>
> Cc: openrisc@lists.librecores.org

Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>

> ---
> v5->v6:
> Remove the special handling in iounmap() because no page is got from
> fixmap pool along with early ioremap code removing in ioremap() - Mike.
>
> arch/openrisc/mm/ioremap.c | 43 +++++---------------------------------
> 1 file changed, 5 insertions(+), 38 deletions(-)
>
> diff --git a/arch/openrisc/mm/ioremap.c b/arch/openrisc/mm/ioremap.c
> index 8ec0dafecf25..cdbcc7e73684 100644
> --- a/arch/openrisc/mm/ioremap.c
> +++ b/arch/openrisc/mm/ioremap.c
> @@ -22,8 +22,6 @@
>
> extern int mem_init_done;
>
> -static unsigned int fixmaps_used __initdata;
> -
> /*
> * Remap an arbitrary physical address space into the kernel virtual
> * address space. Needed when the kernel wants to access high addresses
> @@ -52,24 +50,14 @@ void __iomem *__ref ioremap(phys_addr_t addr, unsigned long size)
> p = addr & PAGE_MASK;
> size = PAGE_ALIGN(last_addr + 1) - p;
>
> - if (likely(mem_init_done)) {
> - area = get_vm_area(size, VM_IOREMAP);
> - if (!area)
> - return NULL;
> - v = (unsigned long)area->addr;
> - } else {
> - if ((fixmaps_used + (size >> PAGE_SHIFT)) > FIX_N_IOREMAPS)
> - return NULL;
> - v = fix_to_virt(FIX_IOREMAP_BEGIN + fixmaps_used);
> - fixmaps_used += (size >> PAGE_SHIFT);
> - }
> + area = get_vm_area(size, VM_IOREMAP);
> + if (!area)
> + return NULL;
> + v = (unsigned long)area->addr;
>
> if (ioremap_page_range(v, v + size, p,
> __pgprot(pgprot_val(PAGE_KERNEL) | _PAGE_CI))) {
> - if (likely(mem_init_done))
> - vfree(area->addr);
> - else
> - fixmaps_used -= (size >> PAGE_SHIFT);
> + vfree(area->addr);
> return NULL;
> }
>
> @@ -79,27 +67,6 @@ EXPORT_SYMBOL(ioremap);
>
> void iounmap(volatile void __iomem *addr)
> {
> - /* If the page is from the fixmap pool then we just clear out
> - * the fixmap mapping.
> - */
> - if (unlikely((unsigned long)addr > FIXADDR_START)) {
> - /* This is a bit broken... we don't really know
> - * how big the area is so it's difficult to know
> - * how many fixed pages to invalidate...
> - * just flush tlb and hope for the best...
> - * consider this a FIXME
> - *
> - * Really we should be clearing out one or more page
> - * table entries for these virtual addresses so that
> - * future references cause a page fault... for now, we
> - * rely on two things:
> - * i) this code never gets called on known boards
> - * ii) invalid accesses to the freed areas aren't made
> - */
> - flush_tlb_all();
> - return;
> - }
> -
> return vfree((void *)(PAGE_MASK & (unsigned long)addr));
> }
> EXPORT_SYMBOL(iounmap);
> --
> 2.34.1
>

--
Sincerely yours,
Mike.