linux-kernel - [PATCH 1/3] mm, x86: Fix warning in ioremap RAM check

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Date:	Fri, 19 Jun 2015 15:44:03 -0600
From:	Toshi Kani <toshi.kani@...com>
To:	tglx@...utronix.de, mingo@...hat.com, hpa@...or.com,
	akpm@...ux-foundation.org
Cc:	travis@....com, roland@...estorage.com, dan.j.williams@...el.com,
	x86@...nel.org, linux-nvdimm@...ts.01.org,
	linux-kernel@...r.kernel.org, Toshi Kani <toshi.kani@...com>
Subject: [PATCH 1/3] mm, x86: Fix warning in ioremap RAM check

__ioremap_caller() calls __ioremap_check_ram() through
walk_system_ram_range() to check if a target range is RAM.
__ioremap_check_ram() has WARN_ONCE() in a wrong place that
it warns when the given range is not RAM.  This misplaced
warning is not exposed since walk_system_ram_range() only
calls __ioremap_check_ram() for RAM ranges.

Move the WARN_ONCE() to the error path of __ioremap_caller(),
and update the message to include the address range.

Signed-off-by: Toshi Kani <toshi.kani@...com>
---
 arch/x86/mm/ioremap.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 70e7444..56f8af7 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -60,8 +60,6 @@ static int __ioremap_check_ram(unsigned long start_pfn, unsigned long nr_pages,
 		    !PageReserved(pfn_to_page(start_pfn + i)))
 			return 1;
 
-	WARN_ONCE(1, "ioremap on RAM pfn 0x%lx\n", start_pfn);
-
 	return 0;
 }
 
@@ -128,8 +126,11 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
 		pfn      = phys_addr >> PAGE_SHIFT;
 		last_pfn = last_addr >> PAGE_SHIFT;
 		if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL,
-					  __ioremap_check_ram) == 1)
+					  __ioremap_check_ram) == 1) {
+			WARN_ONCE(1, "ioremap on RAM at 0x%llx - 0x%llx\n",
+					phys_addr, last_addr);
 			return NULL;
+		}
 	}
 	/*
 	 * Mappings have to be page-aligned
--
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