linux-kernel - [PATCH 2/6] uprobes/x86: Optimize is

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Message-ID: <20250821123656.823296198@infradead.org>
Date: Thu, 21 Aug 2025 14:28:24 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: jolsa@...nel.org,
 oleg@...hat.com,
 andrii@...nel.org,
 mhiramat@...nel.org
Cc: linux-kernel@...r.kernel.org,
 peterz@...radead.org,
 alx@...nel.org,
 eyal.birger@...il.com,
 kees@...nel.org,
 bpf@...r.kernel.org,
 linux-trace-kernel@...r.kernel.org,
 x86@...nel.org,
 songliubraving@...com,
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 john.fastabend@...il.com,
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 rostedt@...dmis.org,
 alan.maguire@...cle.com,
 David.Laight@...LAB.COM,
 thomas@...ch.de,
 mingo@...nel.org,
 rick.p.edgecombe@...el.com
Subject: [PATCH 2/6] uprobes/x86: Optimize is_optimize()

Make is_optimized() return a tri-state and avoid return through
argument. This simplifies things a little.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 arch/x86/kernel/uprobes.c |   34 +++++++++++++---------------------
 1 file changed, 13 insertions(+), 21 deletions(-)

--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -1047,7 +1047,7 @@ static bool __is_optimized(uprobe_opcode
 	return __in_uprobe_trampoline(vaddr + 5 + call->raddr);
 }
 
-static int is_optimized(struct mm_struct *mm, unsigned long vaddr, bool *optimized)
+static int is_optimized(struct mm_struct *mm, unsigned long vaddr)
 {
 	uprobe_opcode_t insn[5];
 	int err;
@@ -1055,8 +1055,7 @@ static int is_optimized(struct mm_struct
 	err = copy_from_vaddr(mm, vaddr, &insn, 5);
 	if (err)
 		return err;
-	*optimized = __is_optimized((uprobe_opcode_t *)&insn, vaddr);
-	return 0;
+	return __is_optimized((uprobe_opcode_t *)&insn, vaddr);
 }
 
 static bool should_optimize(struct arch_uprobe *auprobe)
@@ -1069,17 +1068,14 @@ int set_swbp(struct arch_uprobe *auprobe
 	     unsigned long vaddr)
 {
 	if (should_optimize(auprobe)) {
-		bool optimized = false;
-		int err;
-
 		/*
 		 * We could race with another thread that already optimized the probe,
 		 * so let's not overwrite it with int3 again in this case.
 		 */
-		err = is_optimized(vma->vm_mm, vaddr, &optimized);
-		if (err)
-			return err;
-		if (optimized)
+		int ret = is_optimized(vma->vm_mm, vaddr);
+		if (ret < 0)
+			return ret;
+		if (ret)
 			return 0;
 	}
 	return uprobe_write_opcode(auprobe, vma, vaddr, UPROBE_SWBP_INSN,
@@ -1090,17 +1086,13 @@ int set_orig_insn(struct arch_uprobe *au
 		  unsigned long vaddr)
 {
 	if (test_bit(ARCH_UPROBE_FLAG_CAN_OPTIMIZE, &auprobe->flags)) {
-		struct mm_struct *mm = vma->vm_mm;
-		bool optimized = false;
-		int err;
-
-		err = is_optimized(mm, vaddr, &optimized);
-		if (err)
-			return err;
-		if (optimized) {
-			err = swbp_unoptimize(auprobe, vma, vaddr);
-			WARN_ON_ONCE(err);
-			return err;
+		int ret = is_optimized(vma->vm_mm, vaddr);
+		if (ret < 0)
+			return ret;
+		if (ret) {
+			ret = swbp_unoptimize(auprobe, vma, vaddr);
+			WARN_ON_ONCE(ret);
+			return ret;
 		}
 	}
 	return uprobe_write_opcode(auprobe, vma, vaddr, *(uprobe_opcode_t *)&auprobe->insn,