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[127.0.0.1]) by director3.derp.mail-out.ovh.net (inspect_sender_mail_agent) with SMTP for ; Sun, 26 Jul 2026 17:04:29 +0000 (UTC) Received: from mta6.priv.ovhmail-u2.ea.mail.ovh.net (unknown [10.110.113.67]) by director3.derp.mail-out.ovh.net (Postfix) with ESMTPS id 4h7Skj3KCsz5vVC; Sun, 26 Jul 2026 17:04:29 +0000 (UTC) Received: from kaod.org (unknown [10.1.6.5]) (Authenticated sender: clg@kaod.org) by mta6.priv.ovhmail-u2.ea.mail.ovh.net (Postfix) with ESMTPSA id 1B6971B43E36; Sun, 26 Jul 2026 17:04:26 +0000 (UTC) Authentication-Results:garm.ovh; auth=pass (GARM-113S00762e22185-7b9b-497c-96d9-2cc2a26698c9, 31B54A7FFB7E7F23FF6B7C3EC947DBF3CB6BDBDE) smtp.auth=clg@kaod.org X-OVh-ClientIp:82.64.250.170 Message-ID: <3fba3c54-ea4f-449c-8cd3-f24c516bb31d@kaod.org> Date: Sun, 26 Jul 2026 19:04:25 +0200 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/6] powerpc/xive: remove dead NULL check after GFP_NOFAIL allocation To: Gou Hao , maddy@linux.ibm.com, mpe@ellerman.id.au, npiggin@gmail.com, chleroy@kernel.org, maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, simona@ffwll.ch, bharat@chelsio.com, jgg@ziepe.ca, leon@kernel.org, akpm@linux-foundation.org, namcao@linutronix.de, ynorov@nvidia.com, sshegde@linux.ibm.com, nilay@linux.ibm.com Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, linux-mm@kvack.org, gouhaojake@163.com, kernel@uniontech.com References: <20260724022851.466017-1-gouhao@uniontech.com> <20260724022851.466017-2-gouhao@uniontech.com> Content-Language: en-US, fr From: =?UTF-8?Q?C=C3=A9dric_Le_Goater?= Autocrypt: addr=clg@kaod.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit x-ovh-tracer-id: 4475733607526477032 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: 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 DKIM-Signature: a=rsa-sha256; bh=krixYWDv1svSaZWzY29VuHk3LCe+gkNbeFXejSkZhpM=; c=relaxed/relaxed; d=kaod.org; h=From; s=ovhmo393970-selector1; t=1785085472; v=1; b=X8S4U0suPQzDD/KTpp4BPSUm520wFOWzHCIbmVCsIfU9YnZrdvOnYdVxVlsjZYrWga7m0RiF UXz4Wi8pMb61wLgCH6NIsLfxzBeISoZ9Eef4QFayBeUXrLRIxR53tyZgbfujWbBWqCfQQVATZ4s yxatMiRgJNvxPshv40aYCD2TTWCGZnGHRXiWnwosQbaFIO91NQ8X0xYRrD4e5pfUfTtapXZz3JV 8zZdj2lkez1xd0y1xOKj5iOWLk6jcfsbN4qcu7bdzysdRqHkqG5qTcpAg8EznPMWzgggIEW8UGo /OFvB/Y3d05Pku4dsMx23lBWaUzFUq+HhW/f95+OaHcHQ== As suggested by Andrew, let's change the approach and remove entirely __GFP_NOFAIL instead and make all xive_ipis access paths NULL-safe. On 7/24/26 04:28, Gou Hao wrote: > kzalloc_objs with the __GFP_NOFAIL flag will never return NULL, so the > subsequent NULL check is unreachable dead code. Remove it. > > Signed-off-by: Gou Hao > Reviewed-by: Wentao Guan > Reviewed-by: jiazhenyuan > --- > arch/powerpc/sysdev/xive/common.c | 5 +---- > 1 file changed, 1 insertion(+), 4 deletions(-) > > diff --git a/arch/powerpc/sysdev/xive/common.c b/arch/powerpc/sysdev/xive/common.c > index dadd1f46ec939..f2904a5c2b7bf 100644 > --- a/arch/powerpc/sysdev/xive/common.c > +++ b/arch/powerpc/sysdev/xive/common.c > @@ -1134,9 +1134,6 @@ static int __init xive_init_ipis(void) > > xive_ipis = kzalloc_objs(*xive_ipis, nr_node_ids, > GFP_KERNEL | __GFP_NOFAIL); So let's remove __GFP_NOFAIL here. > - if (!xive_ipis) > - goto out_free_domain; > - Let's keep it now that allocation can really fail. > for_each_node(node) {> struct xive_ipi_desc *xid = &xive_ipis[node]; > struct xive_ipi_alloc_info info = { node }; > @@ -1158,7 +1155,7 @@ static int __init xive_init_ipis(void) > > out_free_xive_ipis: > kfree(xive_ipis); > -out_free_domain: and keep the out_free_domain label > + xive_ipis = NULL; and yes we should add 'xive_ipis = NULL;' > irq_domain_remove(ipi_domain); > out_free_fwnode: > irq_domain_free_fwnode(fwnode); The prepare_cpu() path is broken. To fix, we need to check xive_ipis is not NULL in xive_setup_cpu_ipi() and xive_cleanup_cpu_ipi(). It should be a straight forward local change. Nothing complex. You can test with QEMU. The pSeries and the PowerNV machines are well supported under emulation. Ping me if you need help. Thanks, C.