From: marc.zyngier@arm.com (Marc Zyngier)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH V8 2/8] ACPI: Add new IORT functions to support MSI domain handling
Date: Tue, 16 Aug 2016 11:41:47 +0100 [thread overview]
Message-ID: <57B2EDEB.40903@arm.com> (raw)
In-Reply-To: <1AE640813FDE7649BE1B193DEA596E883BC0E3F2@SHSMSX101.ccr.corp.intel.com>
On 16/08/16 03:15, Zheng, Lv wrote:
> Hi,
>
>> From: linux-acpi-owner at vger.kernel.org [mailto:linux-acpi-owner at vger.kernel.org] On Behalf Of Lorenzo
>> Pieralisi
>> Subject: Re: [PATCH V8 2/8] ACPI: Add new IORT functions to support MSI domain handling
>>
>> On Thu, Aug 11, 2016 at 12:06:32PM +0200, Tomasz Nowicki wrote:
>>
>> [...]
>>
>>> +/**
>>> + * iort_register_domain_token() - register domain token and related ITS ID
>>> + * to the list from where we can get it back later on.
>>> + * @trans_id: ITS ID.
>>> + * @fw_node: Domain token.
>>> + *
>>> + * Returns: 0 on success, -ENOMEM if no memory when allocating list element
>>> + */
>>> +int iort_register_domain_token(int trans_id, struct fwnode_handle *fw_node)
>>> +{
>>> + struct iort_its_msi_chip *its_msi_chip;
>>> +
>>> + its_msi_chip = kzalloc(sizeof(*its_msi_chip), GFP_KERNEL);
>>
>> I spotted this while reworking my ARM SMMU series, this may sleep
>> and that's no good given that we call it within the acpi_probe_lock.
>>
>> Same goes for irq_domain_alloc_fwnode() (that we call in
>> gic_v2_acpi_init()), we have got to fix this usage, I will see with
>> Marc what's the best way to do it.
>
> If we can ensure that all table device probe entries are created
> during link stage or early stage. I think you can safely unlock probe
> lock before invoking acpi_table_parse() in
> __acpi_probe_device_table().
That'd be quite risky, as this lock is the only thing that protects the
acpi_probe_entry pointer (I really wish the ACPI API was less global
variable happy), and I don't see how we can guarantee to only ever
execute this in a single-threaded environment.
An alternative would be to turn the spinlock into a mutex, which will
allow sleeping, and yet provide the required mutual exclusion.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2016-08-16 10:41 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-11 10:06 [PATCH V8 0/8] Introduce ACPI world to ITS irqchip Tomasz Nowicki
2016-08-11 10:06 ` [PATCH V8 1/8] ACPI: I/O Remapping Table (IORT) initial support Tomasz Nowicki
2016-08-12 16:33 ` Lorenzo Pieralisi
2016-08-18 6:25 ` Tomasz Nowicki
2016-08-31 9:30 ` Lorenzo Pieralisi
2016-08-18 10:55 ` Dennis Chen
2016-08-18 11:14 ` Lorenzo Pieralisi
2016-08-19 3:39 ` Dennis Chen
2016-09-02 11:52 ` [Linaro-acpi] " Fu Wei
2016-09-05 6:12 ` Tomasz Nowicki
2016-09-05 15:31 ` Fu Wei
2016-08-11 10:06 ` [PATCH V8 2/8] ACPI: Add new IORT functions to support MSI domain handling Tomasz Nowicki
2016-08-12 16:42 ` Lorenzo Pieralisi
2016-08-16 2:15 ` Zheng, Lv
2016-08-16 10:41 ` Marc Zyngier [this message]
2016-08-11 10:06 ` [PATCH V8 3/8] PCI/MSI: Setup MSI domain on a per-device basis using IORT ACPI table Tomasz Nowicki
2016-08-11 10:06 ` [PATCH V8 4/8] irqchip/gicv3-its: Cleanup for ITS domain initialization Tomasz Nowicki
2016-08-11 10:06 ` [PATCH V8 5/8] irqchip/gicv3-its: Refactor ITS DT init code to prepare for ACPI Tomasz Nowicki
2016-08-17 8:33 ` Hanjun Guo
2016-08-17 15:58 ` Bjorn Helgaas
2016-08-18 6:42 ` Tomasz Nowicki
2016-08-18 6:55 ` Hanjun Guo
2016-08-11 10:06 ` [PATCH V8 6/8] irqchip/gicv3-its: Probe ITS in the ACPI way Tomasz Nowicki
2016-08-11 10:06 ` [PATCH V8 7/8] irqchip/gicv3-its: Factor out PCI-MSI part that might be reused for ACPI Tomasz Nowicki
2016-08-11 10:06 ` [PATCH V8 8/8] irqchip/gicv3-its: Use MADT ITS subtable to do PCI/MSI domain initialization Tomasz Nowicki
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