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From:   Jia He <hejianet@gmail.com>
To:     Russell King <linux@armlinux.org.uk>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
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        Daniel Jordan <daniel.m.jordan@oracle.com>,
        Daniel Vacek <neelx@redhat.com>,
        Eugeniu Rosca <erosca@de.adit-jv.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, Jia He <hejianet@gmail.com>,
        Jia He <jia.he@hxt-semitech.com>
Subject: [PATCH v6 3/5] mm/memblock: introduce memblock_search_pfn_regions()
Date:   Tue,  3 Apr 2018 19:56:17 -0700
Message-Id: <1522810579-7466-4-git-send-email-hejianet@gmail.com>
In-Reply-To: <1522810579-7466-1-git-send-email-hejianet@gmail.com>
References: <1522810579-7466-1-git-send-email-hejianet@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
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This api is to find the region start_pfn and end_pfn of the input pfn.
With this helper, we can improve the loop in early_pfn_valid by reducing
the unnecessary binary searches.

Signed-off-by: Jia He <jia.he@hxt-semitech.com>
---
 include/linux/memblock.h | 2 ++
 mm/memblock.c            | 9 +++++++++
 2 files changed, 11 insertions(+)

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 0257aee..a0127b3 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -203,6 +203,8 @@ void __next_mem_pfn_range(int *idx, int nid, unsigned long *out_start_pfn,
 	     i >= 0; __next_mem_pfn_range(&i, nid, p_start, p_end, p_nid))
 #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
 
+int memblock_search_pfn_regions(unsigned long pfn);
+
 /**
  * for_each_free_mem_range - iterate through free memblock areas
  * @i: u64 used as loop variable
diff --git a/mm/memblock.c b/mm/memblock.c
index ba7c878..0f4004c 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1617,6 +1617,15 @@ static int __init_memblock memblock_search(struct memblock_type *type, phys_addr
 	return -1;
 }
 
+/* search memblock with the input pfn, return the region idx */
+int __init_memblock memblock_search_pfn_regions(unsigned long pfn)
+{
+	struct memblock_type *type = &memblock.memory;
+	int mid = memblock_search(type, PFN_PHYS(pfn));
+
+	return mid;
+}
+
 bool __init memblock_is_reserved(phys_addr_t addr)
 {
 	return memblock_search(&memblock.reserved, addr) != -1;
-- 
2.7.4