From: Logan Gunthorpe <logang@deltatee.com>
To: Bart Van Assche <bvanassche@acm.org>,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org,
linux-nvdimm@lists.01.org, linux-block@vger.kernel.org
Cc: "Jens Axboe" <axboe@kernel.dk>,
"Christian König" <christian.koenig@amd.com>,
"Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
"Alex Williamson" <alex.williamson@redhat.com>,
"Jérôme Glisse" <jglisse@redhat.com>,
"Jason Gunthorpe" <jgg@mellanox.com>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Max Gurtovoy" <maxg@mellanox.com>,
"Christoph Hellwig" <hch@lst.de>
Subject: Re: [PATCH v7 02/13] PCI/P2PDMA: Add sysfs group to display p2pmem stats
Date: Tue, 25 Sep 2018 12:51:09 -0600 [thread overview]
Message-ID: <834b26a8-545c-98e0-fd95-231b701abae6@deltatee.com> (raw)
In-Reply-To: <1537900280.11137.30.camel@acm.org>
On 2018-09-25 12:31 p.m., Bart Van Assche wrote:
> On Tue, 2018-09-25 at 12:15 -0600, Logan Gunthorpe wrote:
>> On 2018-09-25 11:29 a.m., Bart Van Assche wrote:
>>> On Tue, 2018-09-25 at 10:22 -0600, Logan Gunthorpe wrote:
>>>> @@ -83,9 +132,14 @@ static int pci_p2pdma_setup(struct pci_dev *pdev)
>>>>
>>>> pdev->p2pdma = p2p;
>>>>
>>>> + error = sysfs_create_group(&pdev->dev.kobj, &p2pmem_group);
>>>> + if (error)
>>>> + goto out_pool_destroy;
>>>> +
>>>> return 0;
>>>>
>>>> out_pool_destroy:
>>>> + pdev->p2pdma = NULL;
>>>> gen_pool_destroy(p2p->pool);
>>>> out:
>>>> devm_kfree(&pdev->dev, p2p);
>>>
>>> This doesn't look right to me. Shouldn't devm_remove_action() be called instead
>>> of devm_kfree() if sysfs_create_group() fails?
>>
>> That makes no sense to me. We are reversing a devm_kzalloc() not a
>> custom action....
>
> In case what I wrote was not clear: both devm_kzalloc() and
> devm_add_action_or_reset() have to be reversed if sysfs_create_group() fails.
> devm_add_action_or_reset() calls devres_add(). The latter function adds an
> element to the dev->devres_head list. So I think that only calling devm_kfree()
> if sysfs_create_group() fails will lead to corruption of the dev->devres_head
> list.
I don't see how it would corrupt the list. devres_remove() uses
list_del_init() which doesn't require that you only remove the tail from
the list... The way I read the code, you can remove any devm action at
any time.
Logan
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next prev parent reply other threads:[~2018-09-25 18:51 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-25 16:22 [PATCH v7 00/13] Copy Offload in NVMe Fabrics with P2P PCI Memory Logan Gunthorpe
2018-09-25 16:22 ` [PATCH v7 01/13] PCI/P2PDMA: Support peer-to-peer memory Logan Gunthorpe
2018-09-25 17:25 ` Bart Van Assche
2018-09-25 18:09 ` Logan Gunthorpe
2018-09-25 16:22 ` [PATCH v7 02/13] PCI/P2PDMA: Add sysfs group to display p2pmem stats Logan Gunthorpe
2018-09-25 17:29 ` Bart Van Assche
2018-09-25 18:15 ` Logan Gunthorpe
2018-09-25 18:31 ` Bart Van Assche
2018-09-25 18:51 ` Logan Gunthorpe [this message]
2018-09-25 16:22 ` [PATCH v7 03/13] PCI/P2PDMA: Add PCI p2pmem DMA mappings to adjust the bus offset Logan Gunthorpe
2018-09-25 17:33 ` Bart Van Assche
2018-09-25 18:46 ` Logan Gunthorpe
2018-09-25 16:22 ` [PATCH v7 04/13] PCI/P2PDMA: Introduce configfs/sysfs enable attribute helpers Logan Gunthorpe
2018-09-25 16:22 ` [PATCH v7 05/13] docs-rst: Add a new directory for PCI documentation Logan Gunthorpe
2018-09-25 16:22 ` [PATCH v7 06/13] PCI/P2PDMA: Add P2P DMA driver writer's documentation Logan Gunthorpe
2018-09-25 16:22 ` [PATCH v7 07/13] block: Add PCI P2P flag for request queue and check support for requests Logan Gunthorpe
2018-09-25 16:22 ` [PATCH v7 08/13] IB/core: Ensure we map P2P memory correctly in rdma_rw_ctx_[init|destroy]() Logan Gunthorpe
2018-09-25 16:22 ` [PATCH v7 09/13] nvme-pci: Use PCI p2pmem subsystem to manage the CMB Logan Gunthorpe
2018-09-25 16:22 ` [PATCH v7 10/13] nvme-pci: Add support for P2P memory in requests Logan Gunthorpe
2018-09-25 17:11 ` Keith Busch
2018-09-25 17:41 ` Logan Gunthorpe
2018-09-25 17:48 ` Keith Busch
2018-09-25 16:22 ` [PATCH v7 11/13] nvme-pci: Add a quirk for a pseudo CMB Logan Gunthorpe
2018-09-25 16:22 ` [PATCH v7 12/13] nvmet: Introduce helper functions to allocate and free request SGLs Logan Gunthorpe
2018-09-25 16:22 ` [PATCH v7 13/13] nvmet: Optionally use PCI P2P memory Logan Gunthorpe
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