From: Damien Le Moal <damien.lemoal@opensource.wdc.com>
To: Serge Semin <fancer.lancer@gmail.com>
Cc: Serge Semin <Sergey.Semin@baikalelectronics.ru>,
Hans de Goede <hdegoede@redhat.com>, Jens Axboe <axboe@kernel.dk>,
Hannes Reinecke <hare@suse.de>,
Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>,
Pavel Parkhomenko <Pavel.Parkhomenko@baikalelectronics.ru>,
Rob Herring <robh+dt@kernel.org>,
linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org,
devicetree@vger.kernel.org
Subject: Re: [PATCH v4 08/23] ata: libahci_platform: Sanity check the DT child nodes number
Date: Thu, 16 Jun 2022 09:25:48 +0900 [thread overview]
Message-ID: <6d16fe23-012d-39fb-21e5-39ce50f7b03a@opensource.wdc.com> (raw)
In-Reply-To: <20220615205328.chwruabvksdbnaex@mobilestation>
On 2022/06/16 5:53, Serge Semin wrote:
> On Tue, Jun 14, 2022 at 05:23:33PM +0900, Damien Le Moal wrote:
>> On 6/10/22 17:17, Serge Semin wrote:
>>> Having greater than AHCI_MAX_PORTS (32) ports detected isn't that critical
>>> from the further AHCI-platform initialization point of view since
>>> exceeding the ports upper limit will cause allocating more resources than
>>> will be used afterwards. But detecting too many child DT-nodes doesn't
>>> seem right since it's very unlikely to have it on an ordinary platform. In
>>> accordance with the AHCI specification there can't be more than 32 ports
>>> implemented at least due to having the CAP.NP field of 5 bits wide and the
>>> PI register of dword size. Thus if such situation is found the DTB must
>>> have been corrupted and the data read from it shouldn't be reliable. Let's
>>> consider that as an erroneous situation and halt further resources
>>> allocation.
>>>
>>> Note it's logically more correct to have the nports set only after the
>>> initialization value is checked for being sane. So while at it let's make
>>> sure nports is assigned with a correct value.
>>>
>>> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
>>> Reviewed-by: Hannes Reinecke <hare@suse.de>
>>>
>>> ---
>>>
>>> Changelog v2:
>>> - Drop the else word from the child_nodes value checking if-else-if
>>> statement (@Damien) and convert the after-else part into the ternary
>>> operator-based statement.
>>>
>>> Changelog v4:
>>> - Fix some logical mistakes in the patch log. (@Sergei Shtylyov)
>>> ---
>>> drivers/ata/libahci_platform.c | 13 ++++++++++---
>>> 1 file changed, 10 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/ata/libahci_platform.c b/drivers/ata/libahci_platform.c
>>> index 814804582d1d..8aed7b29c7ab 100644
>>> --- a/drivers/ata/libahci_platform.c
>>> +++ b/drivers/ata/libahci_platform.c
>>> @@ -451,15 +451,22 @@ struct ahci_host_priv *ahci_platform_get_resources(struct platform_device *pdev,
>>> }
>>> }
>>>
>>> - hpriv->nports = child_nodes = of_get_child_count(dev->of_node);
>>> + /*
>>> + * Too many sub-nodes most likely means having something wrong with
>>> + * the firmware.
>>> + */
>>> + child_nodes = of_get_child_count(dev->of_node);
>>> + if (child_nodes > AHCI_MAX_PORTS) {
>>> + rc = -EINVAL;
>>> + goto err_out;
>>> + }
>>>
>>> /*
>>> * If no sub-node was found, we still need to set nports to
>>> * one in order to be able to use the
>>> * ahci_platform_[en|dis]able_[phys|regulators] functions.
>>> */
>>> - if (!child_nodes)
>>> - hpriv->nports = 1;
>>> + hpriv->nports = child_nodes ?: 1;
>>
>
>> This change is not necessary and makes the code far less easy to read.
>
> elaborate please. What change? What part of this change makes the code
> less easy to read?
You changed:
if (!child_nodes)
hpriv->nports = 1;
to:
hpriv->nports = child_nodes ?: 1;
That is the same. So the change is not needed in the first place, and worse,
makes the code way harder to read for no good reason.
>
> -Sergey
>
>>
>>>
>>> hpriv->phys = devm_kcalloc(dev, hpriv->nports, sizeof(*hpriv->phys), GFP_KERNEL);
>>> if (!hpriv->phys) {
>>
>>
>> --
>> Damien Le Moal
>> Western Digital Research
--
Damien Le Moal
Western Digital Research
next prev parent reply other threads:[~2022-06-16 0:25 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-10 8:17 [PATCH v4 00/23] ata: ahci: Add DWC/Baikal-T1 AHCI SATA support Serge Semin
2022-06-10 8:17 ` [PATCH v4 01/23] dt-bindings: ata: ahci-platform: Move dma-coherent to sata-common.yaml Serge Semin
2022-06-14 22:02 ` Rob Herring
2022-06-14 22:15 ` Florian Fainelli
2022-06-10 8:17 ` [PATCH v4 02/23] dt-bindings: ata: ahci-platform: Detach common AHCI bindings Serge Semin
2022-06-14 22:16 ` Rob Herring
2022-06-10 8:17 ` [PATCH v4 03/23] dt-bindings: ata: ahci-platform: Clarify common AHCI props constraints Serge Semin
2022-06-14 22:17 ` Rob Herring
2022-06-10 8:17 ` [PATCH v4 04/23] dt-bindings: ata: sata: Extend number of SATA ports Serge Semin
2022-06-10 8:17 ` [PATCH v4 05/23] dt-bindings: ata: sata-brcm: Apply common AHCI schema Serge Semin
2022-06-14 22:15 ` Florian Fainelli
2022-06-14 22:17 ` Rob Herring
2022-06-10 8:17 ` [PATCH v4 06/23] ata: libahci_platform: Convert to using platform devm-ioremap methods Serge Semin
2022-06-10 8:17 ` [PATCH v4 07/23] ata: libahci_platform: Convert to using devm bulk clocks API Serge Semin
2022-06-14 8:22 ` Damien Le Moal
2022-06-15 20:45 ` Serge Semin
2022-06-16 0:23 ` Damien Le Moal
2022-06-17 19:54 ` Serge Semin
2022-06-10 8:17 ` [PATCH v4 08/23] ata: libahci_platform: Sanity check the DT child nodes number Serge Semin
2022-06-14 8:23 ` Damien Le Moal
2022-06-15 20:53 ` Serge Semin
2022-06-16 0:25 ` Damien Le Moal [this message]
2022-06-17 20:18 ` Serge Semin
2022-06-18 6:49 ` Damien Le Moal
2022-06-10 8:17 ` [PATCH v4 09/23] ata: libahci_platform: Parse ports-implemented property in resources getter Serge Semin
2022-06-10 8:17 ` [PATCH v4 10/23] ata: libahci_platform: Introduce reset assertion/deassertion methods Serge Semin
2022-06-10 8:17 ` [PATCH v4 11/23] dt-bindings: ata: ahci: Add platform capability properties Serge Semin
2022-06-14 22:19 ` Rob Herring
2022-06-15 21:56 ` Serge Semin
2022-06-10 8:17 ` [PATCH v4 12/23] ata: libahci: Extend port-cmd flags set with port capabilities Serge Semin
2022-06-14 8:32 ` Damien Le Moal
2022-06-15 20:58 ` Serge Semin
2022-06-16 0:28 ` Damien Le Moal
2022-06-17 20:31 ` Serge Semin
2022-06-18 6:52 ` Damien Le Moal
2022-06-18 8:10 ` Serge Semin
2022-06-28 12:08 ` Serge Semin
2022-06-29 1:35 ` Damien Le Moal
2022-06-29 1:47 ` Serge Semin
2022-06-10 8:17 ` [PATCH v4 13/23] ata: libahci: Discard redundant force_port_map parameter Serge Semin
2022-06-10 8:17 ` [PATCH v4 14/23] ata: libahci: Don't read AHCI version twice in the save-config method Serge Semin
2022-06-10 8:17 ` [PATCH v4 15/23] ata: ahci: Convert __ahci_port_base to accepting hpriv as arguments Serge Semin
2022-06-14 8:38 ` Damien Le Moal
2022-06-15 21:25 ` Serge Semin
2022-06-10 8:17 ` [PATCH v4 16/23] ata: ahci: Introduce firmware-specific caps initialization Serge Semin
2022-06-14 8:42 ` Damien Le Moal
2022-06-15 21:11 ` Serge Semin
2022-06-16 0:29 ` Damien Le Moal
2022-06-17 20:32 ` Serge Semin
2022-06-10 8:17 ` [PATCH v4 17/23] dt-bindings: ata: ahci: Add DWC AHCI SATA controller DT schema Serge Semin
2022-06-14 22:27 ` Rob Herring
2022-06-17 19:37 ` Serge Semin
2022-06-28 12:10 ` Serge Semin
2022-07-06 22:36 ` Rob Herring
2022-07-07 15:25 ` Serge Semin
2022-07-12 20:13 ` Rob Herring
2022-07-12 20:43 ` Serge Semin
2022-06-10 8:17 ` [PATCH v4 18/23] ata: libahci_platform: Add function returning a clock-handle by id Serge Semin
2022-06-14 8:45 ` Damien Le Moal
2022-06-15 21:24 ` Serge Semin
2022-06-10 8:17 ` [PATCH v4 19/23] ata: ahci: Add DWC AHCI SATA controller support Serge Semin
2022-06-10 16:34 ` Randy Dunlap
2022-06-10 21:58 ` Serge Semin
2022-06-10 23:34 ` Randy Dunlap
2022-06-15 21:30 ` Serge Semin
2022-06-16 0:31 ` Damien Le Moal
2022-06-17 20:36 ` Serge Semin
2022-06-18 6:54 ` Damien Le Moal
2022-06-14 8:53 ` Damien Le Moal
2022-06-15 21:48 ` Serge Semin
2022-06-16 0:33 ` Damien Le Moal
2022-06-17 20:34 ` Serge Semin
2022-06-10 8:17 ` [PATCH v4 20/23] dt-bindings: ata: ahci: Add Baikal-T1 AHCI SATA controller DT schema Serge Semin
2022-06-14 22:29 ` Rob Herring
2022-06-17 19:49 ` Serge Semin
2022-06-10 8:17 ` [PATCH v4 21/23] ata: ahci-dwc: Add platform-specific quirks support Serge Semin
2022-06-10 8:18 ` [PATCH v4 22/23] ata: ahci-dwc: Add Baikal-T1 AHCI SATA interface support Serge Semin
2022-06-10 8:18 ` [PATCH v4 23/23] MAINTAINERS: Add maintainers for DWC AHCI SATA driver Serge Semin
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