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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 11 Jun 2019 18:31:27 +0100 Received: from b01ledav004.gho.pok.ibm.com (b01ledav004.gho.pok.ibm.com [9.57.199.109]) by b01cxnp22035.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x5BHVPUl15401272 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 11 Jun 2019 17:31:25 GMT Received: from b01ledav004.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5393F112061; Tue, 11 Jun 2019 17:31:25 +0000 (GMT) Received: from b01ledav004.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 89B10112065; Tue, 11 Jun 2019 17:31:18 +0000 (GMT) Received: from leobras.br.ibm.com (unknown [9.86.24.233]) by b01ledav004.gho.pok.ibm.com (Postfix) with ESMTP; Tue, 11 Jun 2019 17:31:18 +0000 (GMT) Subject: Re: [RFC V3] mm: Generalize and rename notify_page_fault() as kprobe_page_fault() From: Leonardo Bras To: Anshuman Khandual , Christophe Leroy , linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Mark Rutland , Michal Hocko , linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Peter Zijlstra , Catalin Marinas , Dave Hansen , Heiko Carstens , Paul Mackerras , sparclinux@vger.kernel.org, linux-s390@vger.kernel.org, Yoshinori Sato , x86@kernel.org, Russell King , Matthew Wilcox , Ingo Molnar , Andrey Konovalov , Fenghua Yu , Stephen Rothwell , Will Deacon , Andy Lutomirski , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Tony Luck , Martin Schwidefsky , Andrew Morton , linuxppc-dev@lists.ozlabs.org, "David S. Miller" Date: Tue, 11 Jun 2019 14:31:12 -0300 In-Reply-To: <7b0a7afd-2776-0d95-19c5-3e15959744eb@arm.com> References: <1559903655-5609-1-git-send-email-anshuman.khandual@arm.com> <97e9c9b3-89c8-d378-4730-841a900e6800@arm.com> <8dd6168592437378ff4a7c204e0f2962d002b44f.camel@linux.ibm.com> <7b0a7afd-2776-0d95-19c5-3e15959744eb@arm.com> Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-+TvBOjv046XEorglXBMQ" User-Agent: Evolution 3.30.5 (3.30.5-1.fc29) MIME-Version: 1.0 X-TM-AS-GCONF: 00 x-cbid: 19061117-0064-0000-0000-000003ECE701 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00011247; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000286; SDB=6.01216523; UDB=6.00639641; IPR=6.00997622; MB=3.00027266; MTD=3.00000008; XFM=3.00000015; UTC=2019-06-11 17:31:34 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19061117-0065-0000-0000-00003DDA7110 Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-11_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=672 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906110111 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: --=-+TvBOjv046XEorglXBMQ Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2019-06-11 at 10:44 +0530, Anshuman Khandual wrote: >=20 > On 06/10/2019 08:57 PM, Leonardo Bras wrote: > > On Mon, 2019-06-10 at 08:09 +0530, Anshuman Khandual wrote: > > > > > + /* > > > > > + * To be potentially processing a kprobe fault and to be all= owed > > > > > + * to call kprobe_running(), we have to be non-preemptible. > > > > > + */ > > > > > + if (kprobes_built_in() && !preemptible() && !user_mode(regs)= ) { > > > > > + if (kprobe_running() && kprobe_fault_handler(regs, trap)= ) > > > >=20 > > > > don't need an 'if A if B', can do 'if A && B' > > >=20 > > > Which will make it a very lengthy condition check. > >=20 > > Well, is there any problem line-breaking the if condition? > >=20 > > if (A && B && C && > > D && E ) > >=20 > > Also, if it's used only to decide the return value, maybe would be fine > > to do somethink like that: > >=20 > > return (A && B && C && > > D && E );=20 >=20 > Got it. But as Dave and Matthew had pointed out earlier, the current x86 > implementation has better readability. Hence will probably stick with it. >=20 Sure, I agree with them. It's way more readable. --=-+TvBOjv046XEorglXBMQ Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEMdeUgIzgjf6YmUyOlQYWtz9SttQFAlz/5WAACgkQlQYWtz9S ttSg4A/6A45T2BOxIm5qp+PJ+LwF0fbX0ZI762cE3X6nXDk5fJuRrjyQifBfrD0V IVWSUrnOXqarYOmPT3CxT33rW05vGtDWObX+OI6J/QW6qU7jSOD1Db1ZUHL0W3WL 7B27RA3gNmEMugnjmM+JvtMkf5SwTdk3ZLr2IA22revoOBxOF5b8iICzA0HfaXg6 8lFSegTY8C2nNQipkeSS4d3KiObNEA1TVJUFqhwJ/VA6qYMnOpKD6WR58QCOxFaF NIP4ln+HJccwleioGnQ+Q7jFGRD8Hb9zqLKNccpN1MfuZdE9OXcbFB5MXVuPyE/h JVYbITwMXbIxpZe8o6/Yoc875Tz1phA2GeprZlEF3FDbw/tH0tyb6U5o+8UNpOXp YdrNxy1oJRK6ZzhW0+FqgMJVo/BBh/8OV3r9ECwYxR3o8ELPVFAcyqrx2XEU7E6p fBWN/cYXuZFizM0/b2yKd3kO/JIemEdz58/aPOTgJevEb996p7JohS8H8/3lm4gu VcnlAsH9ivKDmkoFzz6JuXWJB19OSohPW8j2p9fqP5LA5snz8o+ehsewTjaVQsPJ eNlp1HQzVumviM07wrZmXzVc0zoUb3YhWHrUL26xcfvtfDZVQ+gIOCH9baNsgcoe U0uI1HQuuUreC4L10sgC2qrlYqbWMUmK5uj6T8fjTRaHlzP1UX8= =i2hD -----END PGP SIGNATURE----- --=-+TvBOjv046XEorglXBMQ--