Thread (21 messages) 21 messages, 3 authors, 2022-08-20

Re: [PATCH 01/11] mm/ioremap: change the return value of io[re|un]map_allowed

From: Alexander Gordeev <agordeev@linux.ibm.com>
Date: 2022-08-04 15:43:38
Also in: linux-mm, lkml

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

Hi Baoquan,
quoted hunk ↗ jump to hunk
--- 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 hunk ↗ jump to hunk
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.
quoted hunk ↗ jump to hunk
@@ -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.
quoted hunk ↗ jump to hunk
@@ -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);
 
-	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.
 		return;
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