From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To: Wei Hu <weh@microsoft.com>
Cc: kys@microsoft.com, haiyangz@microsoft.com,
sthemmin@microsoft.com, wei.liu@kernel.org, robh@kernel.org,
bhelgaas@google.com, linux-hyperv@vger.kernel.org,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
decui@microsoft.com, mikelley@microsoft.com
Subject: Re: [PATCH v2 1/2] PCI: hv: Fix the PCI HyperV probe failure path to release resource properly
Date: Tue, 5 May 2020 16:03:15 +0100 [thread overview]
Message-ID: <20200505150315.GA16228@e121166-lin.cambridge.arm.com> (raw)
In-Reply-To: <20200501053617.24689-1-weh@microsoft.com>
On Fri, May 01, 2020 at 01:36:17PM +0800, Wei Hu wrote:
> Some error cases in hv_pci_probe() were not handled. Fix these error
> paths to release the resourses and clean up the state properly.
This patch does more than that. It adds a variable to store the
number of slots actually allocated - I presume to free only
allocated on slots on the exit path.
Two patches required I am afraid.
> Signed-off-by: Wei Hu <weh@microsoft.com>
> ---
> drivers/pci/controller/pci-hyperv.c | 20 ++++++++++++++++----
> 1 file changed, 16 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
> index e15022ff63e3..e6fac0187722 100644
> --- a/drivers/pci/controller/pci-hyperv.c
> +++ b/drivers/pci/controller/pci-hyperv.c
> @@ -480,6 +480,9 @@ struct hv_pcibus_device {
>
> struct workqueue_struct *wq;
>
> + /* Highest slot of child device with resources allocated */
> + int wslot_res_allocated;
I don't understand why you need an int rather than a u32.
Furthermore, I think a bitmap is more appropriate for what this
variable is used for.
> +
> /* hypercall arg, must not cross page boundary */
> struct hv_retarget_device_interrupt retarget_msi_interrupt_params;
>
> @@ -2847,7 +2850,7 @@ static int hv_send_resources_allocated(struct hv_device *hdev)
> struct hv_pci_dev *hpdev;
> struct pci_packet *pkt;
> size_t size_res;
> - u32 wslot;
> + int wslot;
> int ret;
>
> size_res = (hbus->protocol_version < PCI_PROTOCOL_VERSION_1_2)
> @@ -2900,6 +2903,8 @@ static int hv_send_resources_allocated(struct hv_device *hdev)
> comp_pkt.completion_status);
> break;
> }
> +
> + hbus->wslot_res_allocated = wslot;
> }
>
> kfree(pkt);
> @@ -2918,10 +2923,10 @@ static int hv_send_resources_released(struct hv_device *hdev)
> struct hv_pcibus_device *hbus = hv_get_drvdata(hdev);
> struct pci_child_message pkt;
> struct hv_pci_dev *hpdev;
> - u32 wslot;
> + int wslot;
> int ret;
>
> - for (wslot = 0; wslot < 256; wslot++) {
> + for (wslot = hbus->wslot_res_allocated; wslot >= 0; wslot--) {
> hpdev = get_pcichild_wslot(hbus, wslot);
> if (!hpdev)
> continue;
> @@ -2936,8 +2941,12 @@ static int hv_send_resources_released(struct hv_device *hdev)
> VM_PKT_DATA_INBAND, 0);
> if (ret)
> return ret;
> +
> + hbus->wslot_res_allocated = wslot - 1;
Do you really need to set it at every loop iteration ?
Moreover, I think a bitmap is better suited for what you are doing,
given that you may skip some loop indexes on !hpdev.
> }
>
> + hbus->wslot_res_allocated = -1;
> +
> return 0;
> }
>
> @@ -3037,6 +3046,7 @@ static int hv_pci_probe(struct hv_device *hdev,
> if (!hbus)
> return -ENOMEM;
> hbus->state = hv_pcibus_init;
> + hbus->wslot_res_allocated = -1;
>
> /*
> * The PCI bus "domain" is what is called "segment" in ACPI and other
> @@ -3136,7 +3146,7 @@ static int hv_pci_probe(struct hv_device *hdev,
>
> ret = hv_pci_allocate_bridge_windows(hbus);
> if (ret)
> - goto free_irq_domain;
> + goto exit_d0;
>
> ret = hv_send_resources_allocated(hdev);
> if (ret)
> @@ -3154,6 +3164,8 @@ static int hv_pci_probe(struct hv_device *hdev,
>
> free_windows:
> hv_pci_free_bridge_windows(hbus);
> +exit_d0:
> + (void) hv_pci_bus_exit(hdev, true);
Remove the (void) cast.
Lorenzo
> free_irq_domain:
> irq_domain_remove(hbus->irq_domain);
> free_fwnode:
> --
> 2.20.1
>
next prev parent reply other threads:[~2020-05-05 15:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-01 5:36 [PATCH v2 1/2] PCI: hv: Fix the PCI HyperV probe failure path to release resource properly Wei Hu
2020-05-04 23:42 ` Michael Kelley
2020-05-05 15:03 ` Lorenzo Pieralisi [this message]
2020-05-06 5:36 ` Wei Hu
2020-05-06 11:09 ` Lorenzo Pieralisi
2020-05-06 13:21 ` Wei Hu
2020-05-06 14:55 ` Michael Kelley
2020-05-06 15:21 ` Lorenzo Pieralisi
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