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Re: [Qemu-devel] [PATCH 15/38] ivshmem: Failed realize() can leave migra
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-devel] [PATCH 15/38] ivshmem: Failed realize() can leave migration blocker behind |
Date: |
Wed, 02 Mar 2016 10:54:39 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) |
Marc-André Lureau <address@hidden> writes:
> Hi
>
> On Mon, Feb 29, 2016 at 7:40 PM, Markus Armbruster <address@hidden> wrote:
>> If pci_ivshmem_realize() fails after it created its migration blocker,
>> the blocker is left in place. Fix that by creating it last.
>>
>> Likewise, if it fails after it called fifo8_create(), it leaks fifo
>> memory. Fix that the same way.
>>
>> Signed-off-by: Markus Armbruster <address@hidden>
>> ---
>
> Make sense, I didn't fully get that "realize" was suppose to handle
> failure properly.
>
> Btw, why do you introduce a new err variable? I guess that's easier to
> deal with, perhaps in a following patch.
See explanation inline.
> other than that
> Reviewed-by: Marc-André Lureau <address@hidden>
>
>
>
>> hw/misc/ivshmem.c | 23 ++++++++++++++---------
>> 1 file changed, 14 insertions(+), 9 deletions(-)
>>
>> diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
>> index eb53d9a..1392426 100644
>> --- a/hw/misc/ivshmem.c
>> +++ b/hw/misc/ivshmem.c
>> @@ -824,6 +824,7 @@ static void ivshmem_write_config(PCIDevice *pdev,
>> uint32_t address,
>> static void pci_ivshmem_realize(PCIDevice *dev, Error **errp)
>> {
>> IVShmemState *s = IVSHMEM(dev);
>> + Error *err = NULL;
>> uint8_t *pci_conf;
>> uint8_t attr = PCI_BASE_ADDRESS_SPACE_MEMORY |
>> PCI_BASE_ADDRESS_MEM_PREFETCH;
>> @@ -855,8 +856,6 @@ static void pci_ivshmem_realize(PCIDevice *dev, Error
>> **errp)
>> s->ivshmem_size = size;
>> }
>>
>> - fifo8_create(&s->incoming_fifo, sizeof(int64_t));
>> -
>> /* IRQFD requires MSI */
>> if (ivshmem_has_feature(s, IVSHMEM_IOEVENTFD) &&
>> !ivshmem_has_feature(s, IVSHMEM_MSI)) {
>> @@ -878,12 +877,6 @@ static void pci_ivshmem_realize(PCIDevice *dev, Error
>> **errp)
>> s->role_val = IVSHMEM_MASTER; /* default */
>> }
>>
>> - if (s->role_val == IVSHMEM_PEER) {
>> - error_setg(&s->migration_blocker,
>> - "Migration is disabled when using feature 'peer mode' in
>> device 'ivshmem'");
>> - migrate_add_blocker(s->migration_blocker);
>> - }
>> -
>> pci_conf = dev->config;
>> pci_conf[PCI_COMMAND] = PCI_COMMAND_IO | PCI_COMMAND_MEMORY;
>>
>> @@ -962,7 +955,19 @@ static void pci_ivshmem_realize(PCIDevice *dev, Error
>> **errp)
>> return;
>> }
>>
>> - create_shared_memory_BAR(s, fd, attr, errp);
>> + create_shared_memory_BAR(s, fd, attr, &err);
>> + if (err) {
>> + error_propagate(errp, err);
>> + return;
>> + }
Before my patch, passing errp to create_shared_memory_BAR() was fine,
because it was the last thing the function does.
Now, it isn't: we must bypass the rest of the function on error.
All clear now?
>> + }
>> +
>> + fifo8_create(&s->incoming_fifo, sizeof(int64_t));
>> +
>> + if (s->role_val == IVSHMEM_PEER) {
>> + error_setg(&s->migration_blocker,
>> + "Migration is disabled when using feature 'peer mode' in
>> device 'ivshmem'");
>> + migrate_add_blocker(s->migration_blocker);
>> }
>> }
>>
>> --
>> 2.4.3
>>
>>