linux-kernel - [PATCH 2/3] x86: add a is_e820

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Date:	Thu, 26 Mar 2015 09:32:43 +0100
From:	Christoph Hellwig <hch@....de>
To:	linux-nvdimm@...1.01.org, linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org, x86@...nel.org
Cc:	ross.zwisler@...ux.intel.com, axboe@...nel.dk, boaz@...xistor.com
Subject: [PATCH 2/3] x86: add a is_e820_ram() helper

This will allow to deal with persistent memory which needs to be
treated like ram in many, but not all cases.

Based on an earlier patch from Dave Jiang <dave.jiang@...el.com>.

Signed-off-by: Christoph Hellwig <hch@....de>
Tested-by: Ross Zwisler <ross.zwisler@...ux.intel.com>
---
 arch/x86/kernel/e820.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 46201de..de088e3 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -48,6 +48,11 @@ unsigned long pci_mem_start = 0xaeedbabe;
 EXPORT_SYMBOL(pci_mem_start);
 #endif
 
+static inline bool is_e820_ram(__u32 type)
+{
+	return type == E820_RAM;
+}
+
 /*
  * This function checks if any part of the range <start,end> is mapped
  * with type.
@@ -688,7 +693,7 @@ void __init e820_mark_nosave_regions(unsigned long limit_pfn)
 			register_nosave_region(pfn, PFN_UP(ei->addr));
 
 		pfn = PFN_DOWN(ei->addr + ei->size);
-		if (ei->type != E820_RAM && ei->type != E820_RESERVED_KERN)
+		if (!is_e820_ram(ei->type) && ei->type != E820_RESERVED_KERN)
 			register_nosave_region(PFN_UP(ei->addr), pfn);
 
 		if (pfn >= limit_pfn)
@@ -748,7 +753,7 @@ u64 __init early_reserve_e820(u64 size, u64 align)
 /*
  * Find the highest page frame number we have available
  */
-static unsigned long __init e820_end_pfn(unsigned long limit_pfn, unsigned type)
+static unsigned long __init e820_end_pfn(unsigned long limit_pfn)
 {
 	int i;
 	unsigned long last_pfn = 0;
@@ -759,7 +764,7 @@ static unsigned long __init e820_end_pfn(unsigned long limit_pfn, unsigned type)
 		unsigned long start_pfn;
 		unsigned long end_pfn;
 
-		if (ei->type != type)
+		if (!is_e820_ram(ei->type))
 			continue;
 
 		start_pfn = ei->addr >> PAGE_SHIFT;
@@ -784,12 +789,12 @@ static unsigned long __init e820_end_pfn(unsigned long limit_pfn, unsigned type)
 }
 unsigned long __init e820_end_of_ram_pfn(void)
 {
-	return e820_end_pfn(MAX_ARCH_PFN, E820_RAM);
+	return e820_end_pfn(MAX_ARCH_PFN);
 }
 
 unsigned long __init e820_end_of_low_ram_pfn(void)
 {
-	return e820_end_pfn(1UL<<(32 - PAGE_SHIFT), E820_RAM);
+	return e820_end_pfn(1UL<<(32 - PAGE_SHIFT));
 }
 
 static void early_panic(char *msg)
-- 
1.9.1

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