On Fri, 31 Oct 2014, suravee.suthikulpanit@xxxxxxx wrote:
> +/*
> + * alloc_msi_irq - Allocate MSIs from available MSI bitmap.
> + * @data: Pointer to v2m_data
> + * @nvec: Number of interrupts to allocate
> + * @irq: Pointer to the allocated irq
> + *
> + * Allocates interrupts only if the contiguous range of MSIs
> + * with specified nvec are available. Otherwise return the number
> + * of available interrupts. If none are available, then returns -ENOENT.
And the exact purpose of returning the number of available interrupts
is?
> + */
> +static int alloc_msi_irq(struct v2m_data *data, int nvec, int *irq)
> +{
> + int size = data->nr_spis;
> + int next = size, i = nvec, ret;
> +
> + /* We should never allocate more than available nr_spis */
> + if (i >= size)
> + i = size;
> +
> + spin_lock(&data->msi_cnt_lock);
> +
> + for (; i > 0; i--) {
> + next = bitmap_find_next_zero_area(data->bm,
> + size, 0, i, 0);
> + if (next < size)
> + break;
> + }
That we need a pointless loop here.
> +static int gicv2m_setup_msi_irq(struct msi_chip *chip, struct pci_dev *pdev,
> + struct msi_desc *desc)
> +{
> + int hwirq = 0, virq, avail;
> + struct v2m_data *v2m = container_of(chip, struct v2m_data, msi_chip);
> +
> + if (!desc) {
> + dev_err(&pdev->dev,
> + "MSI setup failed. Invalid msi descriptor\n");
> + return -EINVAL;
> + }
> +
> + avail = alloc_msi_irq(v2m, 1, &hwirq);
> + if (avail != 0) {
So that the caller can turn any non zero return value into -ENOSPC.
> + dev_err(&pdev->dev,
> + "MSI setup failed. Cannnot allocate IRQ\n");
> + return -ENOSPC;
> + }
Brilliant design.
> + virq = __irq_domain_alloc_irqs(v2m->domain, hwirq,
> + 1, NUMA_NO_NODE, v2m, true);
And surely the ability of alloc_msi_irq() to allocate a contiguous
vector space is required to satisfy an hardcoded allocation of ONE
interrupt.
What is guaranteeing that the caller only requests a single interrupt?
> +err_out:
Single error exit which undoes the stuff in the same order it got
initialized is just plain wrong. Ever looked at proper error exits in
other kernel files?
> + of_pci_msi_chip_remove(&v2m->msi_chip);
> + if (v2m->base)
> + iounmap(v2m->base);
> + if (v2m->bm)
> + kzfree(v2m->bm);
Of course you need to zero out the kzalloced bitmap before freeing it
in order not to leak the secrets of a zeroed buffer to the sneaky
black hats, right?
Oh well...
tglx
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
