mm/memory-failure.c: rework the signaling logic in kill_proc

BUS_MCEERR_AR code is only sent when MF_ACTION_REQUIRED is set and the
target is current.  Rework the code to make this clear.

Link: https://lkml.kernel.org/r/20220218090118.1105-4-linmiaohe@huawei.comSigned-off-by: NMiaohe Lin <linmiaohe@huawei.com>
Acked-by: NNaoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/memory-failure.c

@@ -258,16 +258,13 @@ static int kill_proc(struct to_kill *tk, unsigned long pfn, int flags)
 	pr_err("Memory failure: %#lx: Sending SIGBUS to %s:%d due to hardware memory corruption\n",
 			pfn, t->comm, t->pid);
 
-	if (flags & MF_ACTION_REQUIRED) {
-		if (t == current)
-			ret = force_sig_mceerr(BUS_MCEERR_AR,
-					 (void __user *)tk->addr, addr_lsb);
-		else
-			/* Signal other processes sharing the page if they have PF_MCE_EARLY set. */
-			ret = send_sig_mceerr(BUS_MCEERR_AO, (void __user *)tk->addr,
-				addr_lsb, t);
-	} else {
+	if ((flags & MF_ACTION_REQUIRED) && (t == current))
+		ret = force_sig_mceerr(BUS_MCEERR_AR,
+				 (void __user *)tk->addr, addr_lsb);
+	else
 		/*
+		 * Signal other processes sharing the page if they have
+		 * PF_MCE_EARLY set.
 		 * Don't use force here, it's convenient if the signal
 		 * can be temporarily blocked.
 		 * This could cause a loop when the user sets SIGBUS
@@ -275,7 +272,6 @@ static int kill_proc(struct to_kill *tk, unsigned long pfn, int flags)
 		 */
 		ret = send_sig_mceerr(BUS_MCEERR_AO, (void __user *)tk->addr,
 				      addr_lsb, t);  /* synchronous? */
-	}
 	if (ret < 0)
 		pr_info("Memory failure: Error sending signal to %s:%d: %d\n",
 			t->comm, t->pid, ret);