Re: [PATCH 2/4] mm: ioremap: Add arch_ioremap/iounmap_check()

From: Kefeng Wang
Date: Thu Apr 28 2022 - 02:16:51 EST

On 2022/4/28 1:04, Andrew Morton wrote:
On Wed, 27 Apr 2022 20:14:11 +0800 Kefeng Wang <> wrote:

Add special check hook for architecture to verify addr, size
or prot when ioremap() or iounmap(), which will make the generic
ioremap more useful.


--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -964,6 +964,9 @@ static inline void iounmap(volatile void __iomem *addr)
#include <linux/pgtable.h>
+bool arch_ioremap_check(phys_addr_t addr, size_t size, unsigned long prot);
+bool arch_iounmap_check(void __iomem *addr);
Pet peeve. The word "check" is a poor one. I gives no sense of what
the function is checking and it gives no sense of how the function's
return value relates to the thing which it checks.

Maybe it returns 0 on success and -EINVAL on failure. Don't know!

Don't you think that better names would be io_remap_ok(),
io_remap_valid(), io_remap_allowed(), etc?

Will use arch_ioremap/unmap_allowed(), and I'd like to keep return bool

for now if there is no special requirements.

Other than that,

Acked-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>