Hi, Stephen
On 01/15, Stephen Hemminger wrote:
>On Wed, 16 Jan 2019 08:34:52 +0800
>Xiaolong Ye <xiaolong...@intel.com> wrote:
>
>> The comment for igbuio_pci_irqhandler is out of date as the code evolves,
>> remove it to avoid misleading.
>>
>> Signed-off-by: Xiaolong Ye <xiaolong...@intel.com>
>> ---
>> kernel/linux/igb_uio/igb_uio.c | 4 ----
>> 1 file changed, 4 deletions(-)
>>
>> diff --git a/kernel/linux/igb_uio/igb_uio.c b/kernel/linux/igb_uio/igb_uio.c
>> index 3cf394bdf..d6ac51e79 100644
>> --- a/kernel/linux/igb_uio/igb_uio.c
>> +++ b/kernel/linux/igb_uio/igb_uio.c
>> @@ -185,10 +185,6 @@ igbuio_pci_irqcontrol(struct uio_info *info, s32
>> irq_state)
>> return 0;
>> }
>>
>> -/**
>> - * This is interrupt handler which will check if the interrupt is for the
>> right device.
>> - * If yes, disable it here and will be enable later.
>> - */
>> static irqreturn_t
>> igbuio_pci_irqhandler(int irq, void *dev_id)
>> {
>
>The comment is partially correct; if you look at the legacy case.
>
>Maybe better to move the comment to pci_check_and_mask_intx in compat.h?
>I see there is another incorrect comment there.
>
As I tried to understand pci_check_and_mask_intx behavior, I noticed that it
was introduced by commit 399a3f0d ("igb_uio: fix IRQ mode handling"), and it
was derived from igbuio_set_interrupt_mask, however there were two parameters
in igbuio_set_interrupt_mask as below:
static int
igbuio_set_interrupt_mask(struct rte_uio_pci_dev *udev, int32_t state)
while the pci_check_and_mask_intx only has 1 parameter,
static bool pci_check_and_mask_intx(struct pci_dev *pdev)
but in its function body it still use the "state" accorrding to commit 399a3f0d
+static bool pci_check_and_mask_intx(struct pci_dev *pdev)
{
- /* Some function names changes between 3.2.0 and 3.3.0... */
-#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 3, 0)
- pci_unblock_user_cfg_access(pdev);
-#else
- pci_cfg_access_unlock(pdev);
-#endif
+ bool pending;
+ uint32_t status;
+
+ pci_block_user_cfg_access(dev);
+ pci_read_config_dword(pdev, PCI_COMMAND, &status);
+
+ /* interrupt is not ours, goes to out */
+ pending = (((status >> 16) & PCI_STATUS_INTERRUPT) != 0);
+ if (pending) {
+ uint16_t old, new;
+
+ old = status;
+ if (state != 0) <=========================== state still in use
+ new = old & (~PCI_COMMAND_INTX_DISABLE);
+ else
+ new = old | PCI_COMMAND_INTX_DISABLE;
+
+ if (old != new)
+ pci_write_config_word(pdev, PCI_COMMAND, new);
+ }
+ pci_unblock_user_cfg_access(dev);
+
+ return pending;
and later this was fixed as a typo in commit 5b2f8137 ("igb_uio: fix typos for
kernel older than 3.3") which seems not correct.
old = status;
- if (state != 0)
+ if (status != 0)
I feel like that pci_check_and_mask_intx still needs two parameters from code
point of view, please correct me if I was wrong or miss anything, or you think
it's sensible, I'll cook a patch for it.
Thanks,
Xiaolong
