linux-kernel - [RFC PATCH v2 15/16] mm/hwpoison-inject: Rip off duplicated checks

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Date:   Thu, 17 Oct 2019 16:21:22 +0200
From:   Oscar Salvador <osalvador@...e.de>
To:     n-horiguchi@...jp.nec.com
Cc:     mhocko@...nel.org, mike.kravetz@...cle.com, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, Oscar Salvador <osalvador@...e.de>
Subject: [RFC PATCH v2 15/16] mm/hwpoison-inject: Rip off duplicated checks

memory_failure() already performs the same checks, so leave it
to the main routine.

Signed-off-by: Oscar Salvador <osalvador@...e.de>
---
 mm/hwpoison-inject.c | 33 +++------------------------------
 1 file changed, 3 insertions(+), 30 deletions(-)

diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c
index 0c8cdb80fd7d..fdcca3df4283 100644
--- a/mm/hwpoison-inject.c
+++ b/mm/hwpoison-inject.c
@@ -14,49 +14,22 @@ static struct dentry *hwpoison_dir;
 static int hwpoison_inject(void *data, u64 val)
 {
 	unsigned long pfn = val;
-	struct page *p;
-	struct page *hpage;
-	int err;
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
 
-	if (!pfn_valid(pfn))
-		return -ENXIO;
-
-	p = pfn_to_page(pfn);
-	hpage = compound_head(p);
-
-	if (!hwpoison_filter_enable)
-		goto inject;
-
-	shake_page(hpage, 0);
-	/*
-	 * This implies unable to support non-LRU pages.
-	 */
-	if (!PageLRU(hpage) && !PageHuge(p))
-		return 0;
-
-	/*
-	 * do a racy check to make sure PG_hwpoison will only be set for
-	 * the targeted owner (or on a free page).
-	 * memory_failure() will redo the check reliably inside page lock.
-	 */
-	err = hwpoison_filter(hpage);
-	if (err)
-		return 0;
-
-inject:
 	pr_info("Injecting memory failure at pfn %#lx\n", pfn);
 	return memory_failure(pfn, 0);
 }
 
 static int hwpoison_unpoison(void *data, u64 val)
 {
+	unsigned long pfn = val;
+
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
 
-	return unpoison_memory(val);
+	return unpoison_memory(pfn);
 }
 
 DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
-- 
2.12.3