Hi Eric,
On Tue, Mar 01, 2016 at 06:27:46PM +0000, Eric Auger wrote:
>[...]
> +
> +int iommu_get_single_reserved(struct iommu_domain *domain,
> + phys_addr_t addr, int prot,
> + dma_addr_t *iova)
> +{
> + unsigned long order = __ffs(domain->ops->pgsize_bitmap);
> + size_t page_size = 1 << order;
> + phys_addr_t mask = page_size - 1;
> + phys_addr_t aligned_addr = addr & ~mask;
> + phys_addr_t offset = addr - aligned_addr;
> + struct iommu_reserved_binding *b;
> + struct iova *p_iova;
> + struct iova_domain *iovad =
> + (struct iova_domain *)domain->reserved_iova_cookie;
> + int ret;
> +
> + if (!iovad)
> + return -EINVAL;
> +
> + mutex_lock(&domain->reserved_mutex);
I believe this function could get called from the chunk of __setup_irq
that is executed atomically:
* request_threaded_irq
* __setup_irq
* irq_startup
* irq_domain_activate_irq
* msi_domain_activate
* msi_compose
* iommu_get_single_reserved
If this is the case, we should probably use a spinlock to protect the
iova_domain...
> +
> + b = find_reserved_binding(domain, aligned_addr, page_size);
> + if (b) {
> + *iova = b->iova + offset;
> + kref_get(&b->kref);
> + ret = 0;
> + goto unlock;
> + }
> +
> + /* there is no existing reserved iova for this pa */
> + p_iova = alloc_iova(iovad, 1, iovad->dma_32bit_pfn, true);
> + if (!p_iova) {
> + ret = -ENOMEM;
> + goto unlock;
> + }
> + *iova = p_iova->pfn_lo << order;
> +
> + b = kzalloc(sizeof(*b), GFP_KERNEL);
... and GFP_ATOMIC here.
Thanks,
Jean-Philippe
> + if (!b) {
> + ret = -ENOMEM;
> + goto free_iova_unlock;
> + }
> +
> + ret = iommu_map(domain, *iova, aligned_addr, page_size, prot);
> + if (ret)
> + goto free_binding_iova_unlock;
> +
> + kref_init(&b->kref);
> + kref_get(&b->kref);
> + b->domain = domain;
> + b->addr = aligned_addr;
> + b->iova = *iova;
> + b->size = page_size;
> +
> + link_reserved_binding(domain, b);
> +
> + *iova += offset;
> + goto unlock;
> +
> +free_binding_iova_unlock:
> + kfree(b);
> +free_iova_unlock:
> + free_iova(iovad, *iova >> order);
> +unlock:
> + mutex_unlock(&domain->reserved_mutex);
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(iommu_get_single_reserved);
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