Subject: Re: [PATCH] perf expr: Fix return value of ids__new
From:   German Gomez <german.gomez@arm.com>
To:     Miaoqian Lin <linmq006@gmail.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@redhat.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Andi Kleen <ak@linux.intel.com>,
        linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
References: <864ad02d-6afe-791c-f742-56582b633482@arm.com>
 <20211213070956.15119-1-linmq006@gmail.com>
 <d0fabb42-399f-2b72-412b-4f5ba6b9eea4@arm.com>
Message-ID: <b3992bba-04ac-ff0b-7970-8f9cf410d786@arm.com>
Date:   Mon, 13 Dec 2021 16:02:40 +0000
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On 13/12/2021 13:13, German Gomez wrote:
> [...]
>
> On 13/12/2021 07:09, Miaoqian Lin wrote:
>> callers of ids__new() function only do NULL checking for the return
>> value. ids__new() calles hashmap__new(), which may return
>> ERR_PTR(-ENOMEM). Instead of changing the checking one-by-one.
>> return NULL instead of ERR_PTR(-ENOMEM) to keep
>> consistent.
>>
>> Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
>> ---
>>  tools/perf/util/expr.c | 8 +++++++-
>>  1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/perf/util/expr.c b/tools/perf/util/expr.c
>> index 1d532b9fed29..aabdc112300c 100644
>> --- a/tools/perf/util/expr.c
>> +++ b/tools/perf/util/expr.c
>> @@ -65,7 +65,13 @@ static bool key_equal(const void *key1, const void *key2,
>>  
>>  struct hashmap *ids__new(void)
>>  {
>> -	return hashmap__new(key_hash, key_equal, NULL);
>> +	struct hashmap *hash;
>> +
>> +	hash = hashmap__new(key_hash, key_equal, NULL);
>> +	if (IS_ERR(hash))
>> +		return NULL;
>> +	else
>> +		return hash;

Small nitpick but can remove the else branch and simply return at the
end? Your patch still compiles for me but I think most other functions
do that.

>> [...]