linux-kernel - [PATCH v3] tracing/eprobe: no need to check for negative ret value for snprintf

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Date:   Mon,  9 Jan 2023 12:06:25 +0800
From:   Quanfa Fu <quanfafu@...il.com>
To:     rostedt@...dmis.org, mhiramat@...nel.org
Cc:     linux-kernel@...r.kernel.org, linux-trace-kernel@...r.kernel.org,
        Quanfa Fu <quanfafu@...il.com>
Subject: [PATCH v3] tracing/eprobe: no need to check for negative ret value for snprintf

No need to check for negative return value from snprintf() as the
code does not return negative values.

Signed-off-by: Quanfa Fu <quanfafu@...il.com>

-----
V2 -> V3: continue to use snprintf
V1 -> V2: memory allc uses kzalloc and replace snprintf with memcpy
---
 kernel/trace/trace_eprobe.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 352b65e2b910..594ac1d086aa 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -923,17 +923,13 @@ static int trace_eprobe_parse_filter(struct trace_eprobe *ep, int argc, const ch
 
 	p = ep->filter_str;
 	for (i = 0; i < argc; i++) {
-		ret = snprintf(p, len, "%s ", argv[i]);
-		if (ret < 0)
-			goto error;
-		if (ret > len) {
-			ret = -E2BIG;
-			goto error;
-		}
+		if (i)
+			ret = snprintf(p, len, " %s", argv[i]);
+		else
+			ret = snprintf(p, len, "%s", argv[i]);
 		p += ret;
 		len -= ret;
 	}
-	p[-1] = '\0';
 
 	/*
 	 * Ensure the filter string can be parsed correctly. Note, this
-- 
2.31.1