Re: [PATCH] edac: thunderx: Replace pci_alloc_msix_exact

From: Sergei Temerkhanov
Date: Wed May 17 2017 - 19:53:01 EST


On Wed, May 17, 2017 at 8:23 PM, Jan Glauber
<jan.glauber@xxxxxxxxxxxxxxxxxx> wrote:
> On Wed, May 17, 2017 at 06:35:05PM +0300, Sergei Temerkhanov wrote:
>> CIL...
>>
>> On Tue, May 16, 2017 at 12:54 PM, Jan Glauber <jglauber@xxxxxxxxxx> wrote:
>> > Replace the deprecated pci_alloc_msix_exact() with
>> > pci_alloc_irq_vectors().
>> >
>> > Avoid the container_of usage in the interrupt handler
>> > by simply passing the required struct as data to the interrupt
>> > handler.
>> >
>> > Signed-off-by: Jan Glauber <jglauber@xxxxxxxxxx>
>> > ---
>> > drivers/edac/thunderx_edac.c | 91 ++++++++++++++------------------------------
>> > 1 file changed, 28 insertions(+), 63 deletions(-)
>> >
>> > diff --git a/drivers/edac/thunderx_edac.c b/drivers/edac/thunderx_edac.c
>> > index 86d585c..da12804 100644
>> > --- a/drivers/edac/thunderx_edac.c
>> > +++ b/drivers/edac/thunderx_edac.c
>> > @@ -183,7 +183,6 @@ struct lmc_err_ctx {
>> > struct thunderx_lmc {
>> > void __iomem *regs;
>> > struct pci_dev *pdev;
>> > - struct msix_entry msix_ent;
>> >
>> > atomic_t ecc_int;
>> >
>> > @@ -738,18 +737,17 @@ static int thunderx_lmc_probe(struct pci_dev *pdev,
>> > mci->scrub_mode = SCRUB_NONE;
>> >
>> > lmc->pdev = pdev;
>> > - lmc->msix_ent.entry = 0;
>> >
>> > lmc->ring_head = 0;
>> > lmc->ring_tail = 0;
>> >
>> > - ret = pci_enable_msix_exact(pdev, &lmc->msix_ent, 1);
>> > - if (ret) {
>> > + ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSIX);
>> > + if (ret < 0) {
>> > dev_err(&pdev->dev, "Cannot enable interrupt: %d\n", ret);
>> > goto err_free;
>> > }
>> >
>> > - ret = devm_request_threaded_irq(&pdev->dev, lmc->msix_ent.vector,
>> > + ret = devm_request_threaded_irq(&pdev->dev, pci_irq_vector(pdev, 0),
>> > thunderx_lmc_err_isr,
>> > thunderx_lmc_threaded_isr, 0,
>> > "[EDAC] ThunderX LMC", mci);
>> > @@ -1079,7 +1077,6 @@ struct thunderx_ocx {
>> > struct edac_device_ctl_info *edac_dev;
>> >
>> > struct dentry *debugfs;
>> > - struct msix_entry msix_ent[OCX_INTS];
>> >
>> > struct ocx_com_err_ctx com_err_ctx[RING_ENTRIES];
>> > struct ocx_link_err_ctx link_err_ctx[RING_ENTRIES];
>> > @@ -1095,12 +1092,9 @@ struct thunderx_ocx {
>> > #define OCX_OTHER_SIZE (50 * ARRAY_SIZE(ocx_com_link_errors))
>> >
>> > /* This handler is threaded */
>> > -static irqreturn_t thunderx_ocx_com_isr(int irq, void *irq_id)
>> > +static irqreturn_t thunderx_ocx_com_isr(int irq, void *dev_id)
>> > {
>> > - struct msix_entry *msix = irq_id;
>> > - struct thunderx_ocx *ocx = container_of(msix, struct thunderx_ocx,
>> > - msix_ent[msix->entry]);
>> > -
>> > + struct thunderx_ocx *ocx = (struct thunderx_ocx *) dev_id;
>> > int lane;
>> > unsigned long head = ring_pos(ocx->com_ring_head,
>> > ARRAY_SIZE(ocx->com_err_ctx));
>> > @@ -1124,12 +1118,9 @@ static irqreturn_t thunderx_ocx_com_isr(int irq, void *irq_id)
>> > return IRQ_WAKE_THREAD;
>> > }
>> >
>> > -static irqreturn_t thunderx_ocx_com_threaded_isr(int irq, void *irq_id)
>> > +static irqreturn_t thunderx_ocx_com_threaded_isr(int irq, void *dev_id)
>> > {
>> > - struct msix_entry *msix = irq_id;
>> > - struct thunderx_ocx *ocx = container_of(msix, struct thunderx_ocx,
>> > - msix_ent[msix->entry]);
>> > -
>> > + struct thunderx_ocx *ocx = (struct thunderx_ocx *) dev_id;
>> > irqreturn_t ret = IRQ_NONE;
>> >
>> > unsigned long tail;
>> > @@ -1188,16 +1179,14 @@ static irqreturn_t thunderx_ocx_com_threaded_isr(int irq, void *irq_id)
>> > return ret;
>> > }
>> >
>> > -static irqreturn_t thunderx_ocx_lnk_isr(int irq, void *irq_id)
>> > +static irqreturn_t thunderx_ocx_lnk_isr(int irq, void *dev_id)
>> > {
>> > - struct msix_entry *msix = irq_id;
>> > - struct thunderx_ocx *ocx = container_of(msix, struct thunderx_ocx,
>> > - msix_ent[msix->entry]);
>> > + struct thunderx_ocx *ocx = (struct thunderx_ocx *) dev_id;
>> > unsigned long head = ring_pos(ocx->link_ring_head,
>> > ARRAY_SIZE(ocx->link_err_ctx));
>> > struct ocx_link_err_ctx *ctx = &ocx->link_err_ctx[head];
>> >
>> > - ctx->link = msix->entry;
>> > + ctx->link = irq - pci_irq_vector(ocx->pdev, 0);
>>
>> This assumes MSIX vectors are allocated sequentially, as far as I can
>> tell. Is this behavior guaranteed?
>
> From looking at the implementation in pci_irq_vector I would say it is.

What if the implementation changes?

>
>> As a precaution, a check for 0 <= ctx->link <= 2 might need to be added here.
>>
>> > ctx->reg_com_link_int = readq(ocx->regs + OCX_COM_LINKX_INT(ctx->link));
>> >
>> > writeq(ctx->reg_com_link_int, ocx->regs + OCX_COM_LINKX_INT(ctx->link));
>> > @@ -1207,11 +1196,9 @@ static irqreturn_t thunderx_ocx_lnk_isr(int irq, void *irq_id)
>> > return IRQ_WAKE_THREAD;
>> > }
>> >
>> > -static irqreturn_t thunderx_ocx_lnk_threaded_isr(int irq, void *irq_id)
>> > +static irqreturn_t thunderx_ocx_lnk_threaded_isr(int irq, void *dev_id)
>> > {
>> > - struct msix_entry *msix = irq_id;
>> > - struct thunderx_ocx *ocx = container_of(msix, struct thunderx_ocx,
>> > - msix_ent[msix->entry]);
>> > + struct thunderx_ocx *ocx = (struct thunderx_ocx *) dev_id;
>> > irqreturn_t ret = IRQ_NONE;
>> > unsigned long tail;
>> > struct ocx_link_err_ctx *ctx;
>> > @@ -1410,20 +1397,15 @@ static int thunderx_ocx_probe(struct pci_dev *pdev,
>> >
>> > ocx->pdev = pdev;
>> >
>> > - for (i = 0; i < OCX_INTS; i++) {
>> > - ocx->msix_ent[i].entry = i;
>> > - ocx->msix_ent[i].vector = 0;
>> > - }
>> > -
>> > - ret = pci_enable_msix_exact(pdev, ocx->msix_ent, OCX_INTS);
>> > - if (ret) {
>> > + ret = pci_alloc_irq_vectors(pdev, 1, OCX_INTS, PCI_IRQ_MSIX);
>> > + if (ret < 0) {
>> > dev_err(&pdev->dev, "Cannot enable interrupt: %d\n", ret);
>> > goto err_free;
>> > }
>>
>> What happens if less than OCX_INTS vectors are allocated?
>>
>
> The same behaviour as before, it is ignored.

No, pci_enable_msix_exact() fails when it cannot enable the specified
number of interrupts.
This can be achieved with pci_alloc_irq_vectors(pdev, OCX_INTS,
OCX_INTS, PCI_IRQ_MSIX)

>
> Regards,
> Jan
>
>> >
>> > for (i = 0; i < OCX_INTS; i++) {
>> > ret = devm_request_threaded_irq(&pdev->dev,
>> > - ocx->msix_ent[i].vector,
>> > + pci_irq_vector(pdev, i),
>> > (i == 3) ?
>> > thunderx_ocx_com_isr :
>> > thunderx_ocx_lnk_isr,
>> > @@ -1431,7 +1413,7 @@ static int thunderx_ocx_probe(struct pci_dev *pdev,
>> > thunderx_ocx_com_threaded_isr :
>> > thunderx_ocx_lnk_threaded_isr,
>> > 0, "[EDAC] ThunderX OCX",
>> > - &ocx->msix_ent[i]);
>> > + ocx);
>> > if (ret)
>> > goto err_free;
>> > }
>> > @@ -1773,19 +1755,14 @@ struct thunderx_l2c {
>> >
>> > int index;
>> >
>> > - struct msix_entry msix_ent;
>> > -
>> > struct l2c_err_ctx err_ctx[RING_ENTRIES];
>> > unsigned long ring_head;
>> > unsigned long ring_tail;
>> > };
>> >
>> > -static irqreturn_t thunderx_l2c_tad_isr(int irq, void *irq_id)
>> > +static irqreturn_t thunderx_l2c_tad_isr(int irq, void *dev_id)
>> > {
>> > - struct msix_entry *msix = irq_id;
>> > - struct thunderx_l2c *tad = container_of(msix, struct thunderx_l2c,
>> > - msix_ent);
>> > -
>> > + struct thunderx_l2c *tad = (struct thunderx_l2c *) dev_id;
>> > unsigned long head = ring_pos(tad->ring_head, ARRAY_SIZE(tad->err_ctx));
>> > struct l2c_err_ctx *ctx = &tad->err_ctx[head];
>> >
>> > @@ -1812,12 +1789,9 @@ static irqreturn_t thunderx_l2c_tad_isr(int irq, void *irq_id)
>> > return IRQ_WAKE_THREAD;
>> > }
>> >
>> > -static irqreturn_t thunderx_l2c_cbc_isr(int irq, void *irq_id)
>> > +static irqreturn_t thunderx_l2c_cbc_isr(int irq, void *dev_id)
>> > {
>> > - struct msix_entry *msix = irq_id;
>> > - struct thunderx_l2c *cbc = container_of(msix, struct thunderx_l2c,
>> > - msix_ent);
>> > -
>> > + struct thunderx_l2c *cbc = (struct thunderx_l2c *) dev_id;
>> > unsigned long head = ring_pos(cbc->ring_head, ARRAY_SIZE(cbc->err_ctx));
>> > struct l2c_err_ctx *ctx = &cbc->err_ctx[head];
>> >
>> > @@ -1841,12 +1815,9 @@ static irqreturn_t thunderx_l2c_cbc_isr(int irq, void *irq_id)
>> > return IRQ_WAKE_THREAD;
>> > }
>> >
>> > -static irqreturn_t thunderx_l2c_mci_isr(int irq, void *irq_id)
>> > +static irqreturn_t thunderx_l2c_mci_isr(int irq, void *dev_id)
>> > {
>> > - struct msix_entry *msix = irq_id;
>> > - struct thunderx_l2c *mci = container_of(msix, struct thunderx_l2c,
>> > - msix_ent);
>> > -
>> > + struct thunderx_l2c *mci = (struct thunderx_l2c *) dev_id;
>> > unsigned long head = ring_pos(mci->ring_head, ARRAY_SIZE(mci->err_ctx));
>> > struct l2c_err_ctx *ctx = &mci->err_ctx[head];
>> >
>> > @@ -1862,12 +1833,9 @@ static irqreturn_t thunderx_l2c_mci_isr(int irq, void *irq_id)
>> > return IRQ_WAKE_THREAD;
>> > }
>> >
>> > -static irqreturn_t thunderx_l2c_threaded_isr(int irq, void *irq_id)
>> > +static irqreturn_t thunderx_l2c_threaded_isr(int irq, void *dev_id)
>> > {
>> > - struct msix_entry *msix = irq_id;
>> > - struct thunderx_l2c *l2c = container_of(msix, struct thunderx_l2c,
>> > - msix_ent);
>> > -
>> > + struct thunderx_l2c *l2c = (struct thunderx_l2c *) dev_id;
>> > unsigned long tail = ring_pos(l2c->ring_tail, ARRAY_SIZE(l2c->err_ctx));
>> > struct l2c_err_ctx *ctx = &l2c->err_ctx[tail];
>> > irqreturn_t ret = IRQ_NONE;
>> > @@ -2049,20 +2017,17 @@ static int thunderx_l2c_probe(struct pci_dev *pdev,
>> > l2c->ring_head = 0;
>> > l2c->ring_tail = 0;
>> >
>> > - l2c->msix_ent.entry = 0;
>> > - l2c->msix_ent.vector = 0;
>> > -
>> > - ret = pci_enable_msix_exact(pdev, &l2c->msix_ent, 1);
>> > - if (ret) {
>> > + ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSIX);
>> > + if (ret < 0) {
>> > dev_err(&pdev->dev, "Cannot enable interrupt: %d\n", ret);
>> > goto err_free;
>> > }
>> >
>> > - ret = devm_request_threaded_irq(&pdev->dev, l2c->msix_ent.vector,
>> > + ret = devm_request_threaded_irq(&pdev->dev, pci_irq_vector(pdev, 0),
>> > thunderx_l2c_isr,
>> > thunderx_l2c_threaded_isr,
>> > 0, "[EDAC] ThunderX L2C",
>> > - &l2c->msix_ent);
>> > + l2c);
>> > if (ret)
>> > goto err_free;
>> >
>> > --
>> > 1.9.1
>> >
>>
>> Regards,
>> Sergey