[patch 21/22] genirq/msi: Handle PCI/MSI allocation fail in core code

Thomas Gleixner
2021-11-27T01:21:59Z

Get rid of yet another irqdomain callback and let the core code return the
already available information of how many descriptors could be allocated.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
drivers/pci/msi/irqdomain.c | 13 -------------
include/linux/msi.h | 5 +----
kernel/irq/msi.c | 29 +++++++++++++++++++++++++----
3 files changed, 26 insertions(+), 21 deletions(-)

--- a/drivers/pci/msi/irqdomain.c
+++ b/drivers/pci/msi/irqdomain.c
@@ -95,16 +95,6 @@ static int pci_msi_domain_check_cap(stru
return 0;
}

-static int pci_msi_domain_handle_error(struct irq_domain *domain,
- struct msi_desc *desc, int error)
-{
- /* Special handling to support __pci_enable_msi_range() */
- if (pci_msi_desc_is_multi_msi(desc) && error == -ENOSPC)
- return 1;
-
- return error;
-}
-
static void pci_msi_domain_set_desc(msi_alloc_info_t *arg,
struct msi_desc *desc)
{
@@ -115,7 +105,6 @@ static void pci_msi_domain_set_desc(msi_
static struct msi_domain_ops pci_msi_domain_ops_default = {
.set_desc = pci_msi_domain_set_desc,
.msi_check = pci_msi_domain_check_cap,
- .handle_error = pci_msi_domain_handle_error,
};

static void pci_msi_domain_update_dom_ops(struct msi_domain_info *info)
@@ -129,8 +118,6 @@ static void pci_msi_domain_update_dom_op
ops->set_desc = pci_msi_domain_set_desc;
if (ops->msi_check == NULL)
ops->msi_check = pci_msi_domain_check_cap;
- if (ops->handle_error == NULL)
- ops->handle_error = pci_msi_domain_handle_error;
}
}

--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -285,7 +285,6 @@ struct msi_domain_info;
* @msi_check: Callback for verification of the domain/info/dev data
* @msi_prepare: Prepare the allocation of the interrupts in the domain
* @set_desc: Set the msi descriptor for an interrupt
- * @handle_error: Optional error handler if the allocation fails
* @domain_alloc_irqs: Optional function to override the default allocation
* function.
* @domain_free_irqs: Optional function to override the default free
@@ -294,7 +293,7 @@ struct msi_domain_info;
* @get_hwirq, @msi_init and @msi_free are callbacks used by the underlying
* irqdomain.
*
- * @msi_check, @msi_prepare, @handle_error and @set_desc are callbacks used by
+ * @msi_check, @msi_prepare and @set_desc are callbacks used by
* msi_domain_alloc/free_irqs().
*
* @domain_alloc_irqs, @domain_free_irqs can be used to override the
@@ -331,8 +330,6 @@ struct msi_domain_ops {
msi_alloc_info_t *arg);
void (*set_desc)(msi_alloc_info_t *arg,
struct msi_desc *desc);
- int (*handle_error)(struct irq_domain *domain,
- struct msi_desc *desc, int error);
int (*domain_alloc_irqs)(struct irq_domain *domain,
struct device *dev, int nvec);
void (*domain_free_irqs)(struct irq_domain *domain,
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -538,6 +538,27 @@ static bool msi_check_reservation_mode(s
return desc->pci.msi_attrib.is_msix || desc->pci.msi_attrib.can_mask;
}

+static int msi_handle_pci_fail(struct irq_domain *domain, struct msi_desc *desc,
+ int allocated)
+{
+ switch(domain->bus_token) {
+ case DOMAIN_BUS_PCI_MSI:
+ case DOMAIN_BUS_VMD_MSI:
+ if (IS_ENABLED(CONFIG_PCI_MSI))
+ break;
+ fallthrough;
+ default:
+ return -ENOSPC;
+ }
+
+ /* Let a failed PCI multi MSI allocation retry */
+ if (desc->nvec_used > 1)
+ return 1;
+
+ /* If there was a successful allocation let the caller know */
+ return allocated ? allocated : -ENOSPC;
+}
+
int __msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
int nvec)
{
@@ -546,6 +567,7 @@ int __msi_domain_alloc_irqs(struct irq_d
struct irq_data *irq_data;
struct msi_desc *desc;
msi_alloc_info_t arg = { };
+ int allocated = 0;
int i, ret, virq;
bool can_reserve;

@@ -560,16 +582,15 @@ int __msi_domain_alloc_irqs(struct irq_d
dev_to_node(dev), &arg, false,
desc->affinity);
if (virq < 0) {
- ret = -ENOSPC;
- if (ops->handle_error)
- ret = ops->handle_error(domain, desc, ret);
- return ret;
+ ret = msi_handle_pci_fail(domain, desc, allocated);
+ goto cleanup;
}

for (i = 0; i < desc->nvec_used; i++) {
irq_set_msi_desc_off(virq, i, desc);
irq_debugfs_copy_devname(virq + i, dev);
}
+ allocated++;
}

can_reserve = msi_check_reservation_mode(domain, info, dev);