PCI: iproc: Fix multi-MSI base vector number allocation

Commit fc54bae28818 ("PCI: iproc: Allow allocation of multiple MSIs")
introduced multi-MSI support with a broken allocation mechanism (it failed
to reserve the proper number of bits from the inner domain).  Natural
alignment of the base vector number was also not guaranteed.

Link: https://lore.kernel.org/r/20210622152630.40842-1-sbodomerle@gmail.com
Fixes: fc54bae28818 ("PCI: iproc: Allow allocation of multiple MSIs")
Reported-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Sandor Bodo-Merle <sbodomerle@gmail.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Acked-by: Pali Rohár <pali@kernel.org>
Acked-by: Ray Jui <ray.jui@broadcom.com>

diff --git a/drivers/pci/controller/pcie-iproc-msi.c b/drivers/pci/controller/pcie-iproc-msi.c
index eede4e8..557d93d 100644 (file)
--- a/drivers/pci/controller/pcie-iproc-msi.c
+++ b/drivers/pci/controller/pcie-iproc-msi.c
@@ -252,18 +252,18 @@ static int iproc_msi_irq_domain_alloc(struct irq_domain *domain,
 
        mutex_lock(&msi->bitmap_lock);
 
-       /* Allocate 'nr_cpus' number of MSI vectors each time */
-       hwirq = bitmap_find_next_zero_area(msi->bitmap, msi->nr_msi_vecs, 0,
-                                          msi->nr_cpus, 0);
-       if (hwirq < msi->nr_msi_vecs) {
-               bitmap_set(msi->bitmap, hwirq, msi->nr_cpus);
-       } else {
-               mutex_unlock(&msi->bitmap_lock);
-               return -ENOSPC;
-       }
+       /*
+        * Allocate 'nr_irqs' multiplied by 'nr_cpus' number of MSI vectors
+        * each time
+        */
+       hwirq = bitmap_find_free_region(msi->bitmap, msi->nr_msi_vecs,
+                                       order_base_2(msi->nr_cpus * nr_irqs));
 
        mutex_unlock(&msi->bitmap_lock);
 
+       if (hwirq < 0)
+               return -ENOSPC;
+
        for (i = 0; i < nr_irqs; i++) {
                irq_domain_set_info(domain, virq + i, hwirq + i,
                                    &iproc_msi_bottom_irq_chip,
@@ -284,7 +284,8 @@ static void iproc_msi_irq_domain_free(struct irq_domain *domain,
        mutex_lock(&msi->bitmap_lock);
 
        hwirq = hwirq_to_canonical_hwirq(msi, data->hwirq);
-       bitmap_clear(msi->bitmap, hwirq, msi->nr_cpus);
+       bitmap_release_region(msi->bitmap, hwirq,
+                             order_base_2(msi->nr_cpus * nr_irqs));
 
        mutex_unlock(&msi->bitmap_lock);