mm/memory-failure.c: replace "MCE" with "Memory failure"

HWPoison was specific to some particular x86 platforms.  And it is often
seen as high level machine check handler.  And therefore, 'MCE' is used
for the format prefix of printk().  However, 'PowerNV' has also used
HWPoison for handling memory errors[1], so 'MCE' is no longer suitable
to memory_failure.c.

Additionally, 'MCE' and 'Memory failure' have different context.  The
former belongs to exception context and the latter belongs to process
context.  Furthermore, HWPoison can also be used for off-lining those
sub-health pages that do not trigger any machine check exception.

This patch aims to replace 'MCE' with a more appropriate prefix.

[1] commit 75eb3d9b60c2 ("powerpc/powernv: Get FSP memory errors
and plumb into memory poison infrastructure.")

Signed-off-by: Chen Yucong <slaoub@gmail.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index ca5acee..2fcca6b 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -184,8 +184,8 @@
 	struct siginfo si;
 	int ret;
 
-	pr_err("MCE %#lx: Killing %s:%d due to hardware memory corruption\n",
-	       pfn, t->comm, t->pid);
+	pr_err("Memory failure: %#lx: Killing %s:%d due to hardware memory corruption\n",
+		pfn, t->comm, t->pid);
 	si.si_signo = SIGBUS;
 	si.si_errno = 0;
 	si.si_addr = (void *)addr;
@@ -208,7 +208,7 @@
 		ret = send_sig_info(SIGBUS, &si, t);  /* synchronous? */
 	}
 	if (ret < 0)
-		pr_info("MCE: Error sending signal to %s:%d: %d\n",
+		pr_info("Memory failure: Error sending signal to %s:%d: %d\n",
 			t->comm, t->pid, ret);
 	return ret;
 }
@@ -289,7 +289,7 @@
 	} else {
 		tk = kmalloc(sizeof(struct to_kill), GFP_ATOMIC);
 		if (!tk) {
-			pr_err("MCE: Out of memory while machine check handling\n");
+			pr_err("Memory failure: Out of memory while machine check handling\n");
 			return;
 		}
 	}
@@ -303,7 +303,7 @@
 	 * a SIGKILL because the error is not contained anymore.
 	 */
 	if (tk->addr == -EFAULT) {
-		pr_info("MCE: Unable to find user space address %lx in %s\n",
+		pr_info("Memory failure: Unable to find user space address %lx in %s\n",
 			page_to_pfn(p), tsk->comm);
 		tk->addr_valid = 0;
 	}
@@ -334,7 +334,7 @@
 			 * signal and then access the memory. Just kill it.
 			 */
 			if (fail || tk->addr_valid == 0) {
-				pr_err("MCE %#lx: forcibly killing %s:%d because of failure to unmap corrupted page\n",
+				pr_err("Memory failure: %#lx: forcibly killing %s:%d because of failure to unmap corrupted page\n",
 				       pfn, tk->tsk->comm, tk->tsk->pid);
 				force_sig(SIGKILL, tk->tsk);
 			}
@@ -347,7 +347,7 @@
 			 */
 			else if (kill_proc(tk->tsk, tk->addr, trapno,
 					      pfn, page, flags) < 0)
-				pr_err("MCE %#lx: Cannot send advisory machine check signal to %s:%d\n",
+				pr_err("Memory failure: %#lx: Cannot send advisory machine check signal to %s:%d\n",
 				       pfn, tk->tsk->comm, tk->tsk->pid);
 		}
 		put_task_struct(tk->tsk);
@@ -559,7 +559,7 @@
  */
 static int me_unknown(struct page *p, unsigned long pfn)
 {
-	pr_err("MCE %#lx: Unknown page state\n", pfn);
+	pr_err("Memory failure: %#lx: Unknown page state\n", pfn);
 	return MF_FAILED;
 }
 
@@ -604,11 +604,12 @@
 	if (mapping->a_ops->error_remove_page) {
 		err = mapping->a_ops->error_remove_page(mapping, p);
 		if (err != 0) {
-			pr_info("MCE %#lx: Failed to punch page: %d\n",
+			pr_info("Memory failure: %#lx: Failed to punch page: %d\n",
 				pfn, err);
 		} else if (page_has_private(p) &&
 				!try_to_release_page(p, GFP_NOIO)) {
-			pr_info("MCE %#lx: failed to release buffers\n", pfn);
+			pr_info("Memory failure: %#lx: failed to release buffers\n",
+				pfn);
 		} else {
 			ret = MF_RECOVERED;
 		}
@@ -620,7 +621,8 @@
 		if (invalidate_inode_page(p))
 			ret = MF_RECOVERED;
 		else
-			pr_info("MCE %#lx: Failed to invalidate\n", pfn);
+			pr_info("Memory failure: %#lx: Failed to invalidate\n",
+				pfn);
 	}
 	return ret;
 }
@@ -833,7 +835,7 @@
 {
 	trace_memory_failure_event(pfn, type, result);
 
-	pr_err("MCE %#lx: recovery action for %s: %s\n",
+	pr_err("Memory failure: %#lx: recovery action for %s: %s\n",
 		pfn, action_page_types[type], action_name[result]);
 }
 
@@ -849,7 +851,7 @@
 	if (ps->action == me_swapcache_dirty && result == MF_DELAYED)
 		count--;
 	if (count != 0) {
-		pr_err("MCE %#lx: %s still referenced by %d users\n",
+		pr_err("Memory failure: %#lx: %s still referenced by %d users\n",
 		       pfn, action_page_types[ps->type], count);
 		result = MF_FAILED;
 	}
@@ -882,7 +884,7 @@
 		 * tries to touch the "partially handled" page.
 		 */
 		if (!PageAnon(head)) {
-			pr_err("MCE: %#lx: non anonymous thp\n",
+			pr_err("Memory failure: %#lx: non anonymous thp\n",
 				page_to_pfn(page));
 			return 0;
 		}
@@ -892,7 +894,8 @@
 		if (head == compound_head(page))
 			return 1;
 
-		pr_info("MCE: %#lx cannot catch tail\n", page_to_pfn(page));
+		pr_info("Memory failure: %#lx cannot catch tail\n",
+			page_to_pfn(page));
 		put_page(head);
 	}
 
@@ -931,12 +934,13 @@
 		return SWAP_SUCCESS;
 
 	if (PageKsm(p)) {
-		pr_err("MCE %#lx: can't handle KSM pages.\n", pfn);
+		pr_err("Memory failure: %#lx: can't handle KSM pages.\n", pfn);
 		return SWAP_FAIL;
 	}
 
 	if (PageSwapCache(p)) {
-		pr_err("MCE %#lx: keeping poisoned page in swap cache\n", pfn);
+		pr_err("Memory failure: %#lx: keeping poisoned page in swap cache\n",
+			pfn);
 		ttu |= TTU_IGNORE_HWPOISON;
 	}
 
@@ -954,7 +958,7 @@
 		} else {
 			kill = 0;
 			ttu |= TTU_IGNORE_HWPOISON;
-			pr_info("MCE %#lx: corrupted page was clean: dropped without side effects\n",
+			pr_info("Memory failure: %#lx: corrupted page was clean: dropped without side effects\n",
 				pfn);
 		}
 	}
@@ -972,7 +976,7 @@
 
 	ret = try_to_unmap(hpage, ttu);
 	if (ret != SWAP_SUCCESS)
-		pr_err("MCE %#lx: failed to unmap page (mapcount=%d)\n",
+		pr_err("Memory failure: %#lx: failed to unmap page (mapcount=%d)\n",
 		       pfn, page_mapcount(hpage));
 
 	/*
@@ -1040,14 +1044,16 @@
 		panic("Memory failure from trap %d on page %lx", trapno, pfn);
 
 	if (!pfn_valid(pfn)) {
-		pr_err("MCE %#lx: memory outside kernel control\n", pfn);
+		pr_err("Memory failure: %#lx: memory outside kernel control\n",
+			pfn);
 		return -ENXIO;
 	}
 
 	p = pfn_to_page(pfn);
 	orig_head = hpage = compound_head(p);
 	if (TestSetPageHWPoison(p)) {
-		pr_err("MCE %#lx: already hardware poisoned\n", pfn);
+		pr_err("Memory failure: %#lx: already hardware poisoned\n",
+			pfn);
 		return 0;
 	}
 
@@ -1112,9 +1118,11 @@
 		if (!PageAnon(hpage) || unlikely(split_huge_page(hpage))) {
 			unlock_page(hpage);
 			if (!PageAnon(hpage))
-				pr_err("MCE: %#lx: non anonymous thp\n", pfn);
+				pr_err("Memory failure: %#lx: non anonymous thp\n",
+					pfn);
 			else
-				pr_err("MCE: %#lx: thp split failed\n", pfn);
+				pr_err("Memory failure: %#lx: thp split failed\n",
+					pfn);
 			if (TestClearPageHWPoison(p))
 				num_poisoned_pages_sub(nr_pages);
 			put_hwpoison_page(p);
@@ -1178,7 +1186,7 @@
 	 * unpoison always clear PG_hwpoison inside page lock
 	 */
 	if (!PageHWPoison(p)) {
-		pr_err("MCE %#lx: just unpoisoned\n", pfn);
+		pr_err("Memory failure: %#lx: just unpoisoned\n", pfn);
 		num_poisoned_pages_sub(nr_pages);
 		unlock_page(hpage);
 		put_hwpoison_page(hpage);
@@ -1395,25 +1403,25 @@
 	page = compound_head(p);
 
 	if (!PageHWPoison(p)) {
-		unpoison_pr_info("MCE: Page was already unpoisoned %#lx\n",
+		unpoison_pr_info("Unpoison: Page was already unpoisoned %#lx\n",
 				 pfn, &unpoison_rs);
 		return 0;
 	}
 
 	if (page_count(page) > 1) {
-		unpoison_pr_info("MCE: Someone grabs the hwpoison page %#lx\n",
+		unpoison_pr_info("Unpoison: Someone grabs the hwpoison page %#lx\n",
 				 pfn, &unpoison_rs);
 		return 0;
 	}
 
 	if (page_mapped(page)) {
-		unpoison_pr_info("MCE: Someone maps the hwpoison page %#lx\n",
+		unpoison_pr_info("Unpoison: Someone maps the hwpoison page %#lx\n",
 				 pfn, &unpoison_rs);
 		return 0;
 	}
 
 	if (page_mapping(page)) {
-		unpoison_pr_info("MCE: the hwpoison page has non-NULL mapping %#lx\n",
+		unpoison_pr_info("Unpoison: the hwpoison page has non-NULL mapping %#lx\n",
 				 pfn, &unpoison_rs);
 		return 0;
 	}
@@ -1424,7 +1432,7 @@
 	 * In such case, we yield to memory_failure() and make unpoison fail.
 	 */
 	if (!PageHuge(page) && PageTransHuge(page)) {
-		unpoison_pr_info("MCE: Memory failure is now running on %#lx\n",
+		unpoison_pr_info("Unpoison: Memory failure is now running on %#lx\n",
 				 pfn, &unpoison_rs);
 		return 0;
 	}
@@ -1439,13 +1447,13 @@
 		 * to the end.
 		 */
 		if (PageHuge(page)) {
-			unpoison_pr_info("MCE: Memory failure is now running on free hugepage %#lx\n",
+			unpoison_pr_info("Unpoison: Memory failure is now running on free hugepage %#lx\n",
 					 pfn, &unpoison_rs);
 			return 0;
 		}
 		if (TestClearPageHWPoison(p))
 			num_poisoned_pages_dec();
-		unpoison_pr_info("MCE: Software-unpoisoned free page %#lx\n",
+		unpoison_pr_info("Unpoison: Software-unpoisoned free page %#lx\n",
 				 pfn, &unpoison_rs);
 		return 0;
 	}
@@ -1458,7 +1466,7 @@
 	 * the free buddy page pool.
 	 */
 	if (TestClearPageHWPoison(page)) {
-		unpoison_pr_info("MCE: Software-unpoisoned page %#lx\n",
+		unpoison_pr_info("Unpoison: Software-unpoisoned page %#lx\n",
 				 pfn, &unpoison_rs);
 		num_poisoned_pages_sub(nr_pages);
 		freeit = 1;