From: Alexei Starovoitov <ast@plumgrid•com>
To: Daniel Borkmann <daniel@iogearbox•net>,
"David S. Miller" <davem@davemloft•net>
Cc: Michael Holzheu <holzheu@linux•vnet.ibm.com>,
Fengguang Wu <fengguang.wu@intel•com>,
netdev@vger•kernel.org
Subject: Re: [PATCH net-next] test_bpf: fix sparse warnings
Date: Thu, 14 May 2015 10:18:28 -0700 [thread overview]
Message-ID: <5554D8E4.50500@plumgrid.com> (raw)
In-Reply-To: <5554C8F7.5080002@iogearbox.net>
On 5/14/15 9:10 AM, Daniel Borkmann wrote:
> On 05/14/2015 05:40 AM, Alexei Starovoitov wrote:
>> From: Michael Holzheu <holzheu@linux•vnet.ibm.com>
>>
>> Fix several sparse warnings like:
>> lib/test_bpf.c:1824:25: sparse: constant 4294967295 is so big it is long
>> lib/test_bpf.c:1878:25: sparse: constant 0x0000ffffffff0000 is so big
>> it is long
>>
>> Fixes: cffc642d93f9 ("test_bpf: add 173 new testcases for eBPF")
>> Reported-by: Fengguang Wu <fengguang.wu@intel•com>
>> Signed-off-by: Michael Holzheu <holzheu@linux•vnet.ibm.com>
>> Signed-off-by: Alexei Starovoitov <ast@plumgrid•com>
>> ---
>> lib/test_bpf.c | 122
>> ++++++++++++++++++++++++++++----------------------------
>> 1 file changed, 61 insertions(+), 61 deletions(-)
>>
> ...
>> {
>> "ALU_MOV_K: 0x0000ffffffff0000 = 0x00000000ffffffff",
>> .u.insns_int = {
>> - BPF_LD_IMM64(R2, 0x0000ffffffff0000),
>> - BPF_LD_IMM64(R3, 0x00000000ffffffff),
>> + BPF_LD_IMM64(R2, 0x0000ffffffff0000LL),
>> + BPF_LD_IMM64(R3, 0x00000000ffffffffLL),
>
> Should have been ULL, no?
why? The data type is derived from the value.
0xffff0000ffffffffLL is unsigned. GCC does the right thing. Here
we're just shutting up sparse.
I actually most of the time use LL as well since it's one character
shorter.
Ex:
printf("%llx\n", 0xffff0000ffffffffLL >> 32);
printf("%llx\n", 0xffff0000ffffffffULL >> 32);
printf("%llx\n", ((long long)0xffff0000ffffffff) >> 32);
printf("%llx\n", ((unsigned long long)0xffff0000ffffffff) >> 32);
will print:
ffff0000
ffff0000
ffffffffffff0000
ffff0000
I also think that sparse shouldn't be complaining about this.
The suffix is redundant.
> Anyway, the BPF_LD_IMM64() macro will cast it
> correctly anyway.
it's correct even without LL.
It's not a bugfix. It's 'mute the sparse' patch :)
> Other than that:
>
> Acked-by: Daniel Borkmann <daniel@iogearbox•net>
next prev parent reply other threads:[~2015-05-14 17:18 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-14 3:40 [PATCH net-next] test_bpf: fix sparse warnings Alexei Starovoitov
2015-05-14 16:10 ` Daniel Borkmann
2015-05-14 17:18 ` Alexei Starovoitov [this message]
2015-05-14 18:17 ` Daniel Borkmann
2015-05-15 2:47 ` David Miller
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