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[2003:d8:2f0a:7f00:fad7:3bc9:69d:31f]) by smtp.gmail.com with ESMTPSA id p14sm7851740wro.3.2021.08.09.02.23.25 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 09 Aug 2021 02:23:25 -0700 (PDT) Subject: Re: [PATCH 3/5] mm: gup: remove useless BUG_ON in __get_user_pages() To: Miaohe Lin , akpm@linux-foundation.org Cc: imbrenda@linux.ibm.com, kirill.shutemov@linux.intel.com, jack@suse.cz, jhubbard@nvidia.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20210807093620.21347-1-linmiaohe@huawei.com> <20210807093620.21347-4-linmiaohe@huawei.com> From: David Hildenbrand Organization: Red Hat Message-ID: Date: Mon, 9 Aug 2021 11:23:25 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210807093620.21347-4-linmiaohe@huawei.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 1BC4B6022E1E Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=JNTxU1lK; dmarc=pass (policy=none) header.from=redhat.com; spf=none (imf10.hostedemail.com: domain of david@redhat.com has no SPF policy when checking 170.10.133.124) smtp.mailfrom=david@redhat.com X-Stat-Signature: 68yomjhjipic4a663oyu6un593oprj7p X-HE-Tag: 1628501008-810970 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 07.08.21 11:36, Miaohe Lin wrote: > Indeed, this BUG_ON couldn't catch anything useful. We are sure ret == 0 > here because we would already bail out if ret != 0 and ret is untouched > till here. > > Signed-off-by: Miaohe Lin > --- > mm/gup.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/mm/gup.c b/mm/gup.c > index d6056dcab02c..d7e4507de6b1 100644 > --- a/mm/gup.c > +++ b/mm/gup.c > @@ -1149,7 +1149,6 @@ static long __get_user_pages(struct mm_struct *mm, > * We must stop here. > */ > BUG_ON(gup_flags & FOLL_NOWAIT); > - BUG_ON(ret != 0); > goto out; > } > continue; > Reviewed-by: David Hildenbrand -- Thanks, David / dhildenb