On Sat, Aug 06, 2022 at 10:29:03AM +0800, Kefeng Wang wrote:

On 2022/8/4 23:42, Alexander Gordeev wrote:

quoted

On Mon, Aug 01, 2022 at 10:40:19PM +0800, Baoquan He wrote:

Hi Baoquan,

quoted

--- a/arch/arm64/mm/ioremap.c
+++ b/arch/arm64/mm/ioremap.c

@@ -3,19 +3,20 @@
  #include <linux/mm.h>
  #include <linux/io.h>
-bool ioremap_allowed(phys_addr_t phys_addr, size_t size, unsigned long prot)
+void __iomem *ioremap_allowed(phys_addr_t phys_addr, size_t size, unsigned long prot)
  {
  	unsigned long last_addr = phys_addr + size - 1;
+	int ret = -EINVAL;

If ret variable is really needed?

quoted

diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index 72974cb81343..d72eb310fb3c 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h

@@ -967,26 +967,27 @@ static inline void iounmap(volatile void __iomem *addr)
  /*
   * Arch code can implement the following two hooks when using GENERIC_IOREMAP
   * ioremap_allowed() return a bool,
- *   - true means continue to remap
- *   - false means skip remap and return directly
+ *   - IS_ERR means return an error
+ *   - NULL means continue to remap
+ *   - a non-NULL, non-IS_ERR pointer is returned directly

If ioremap_allowed() returns a valid pointer, then the function name
is not as precise anymore.

Maybe use arch_ioremap/unmap as before, or some better name.

quoted

quoted

@@ -28,8 +29,11 @@ void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
  	phys_addr -= offset;
  	size = PAGE_ALIGN(size + offset);
-	if (!ioremap_allowed(phys_addr, size, prot))
+	base = ioremap_allowed(phys_addr, size, prot);
+	if (IS_ERR(base))
  		return NULL;
+	else if (base)
+		return base;

It is probably just me, but the base name bit misleading here.

We could reuse vaddr, not add new base.

vaddr name is wrong AFAICT. ioremap_allowed() returns __iomem address,
not the virtual one.

quoted

quoted

@@ -50,9 +54,9 @@ EXPORT_SYMBOL(ioremap_prot);
  void iounmap(volatile void __iomem *addr)
  {
-	void *vaddr = (void *)((unsigned long)addr & PAGE_MASK);
+	void __iomem *vaddr = (void __iomem *)((unsigned long)addr & PAGE_MASK);

Same here.

quoted

quoted

-	if (!iounmap_allowed(vaddr))
+	if (iounmap_allowed(vaddr))

I guess, iounmap_allowed() should accept void __iomem *, not void *.
Then addr needs to be passed to iounmap_allowed() not vaddr.

The following is_vmalloc_addr()  and vunmap() in iounmap() use void *,

so we could simply use void* for iounmap_allowed().

iounmap_allowed() accepts void __iomem * and I that looks correct to me.

Passing void * on the other hand means you pass a pointer that
in theory differs from what architecture previously returned
with ioremap_allowed() and "knows" nothing about.

I think you need to pass addr to iounmap_allowed() as is.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel