[PATCH 5.10 166/243] PCI: iproc: Fix multi-MSI base vector number allocation

Greg Kroah-Hartman
2021-07-19T17:22:42Z

From: Sandor Bodo-Merle <sbodomerle@gmail.com>

[ Upstream commit e673d697b9a234fc3544ac240e173cef8c82b349 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/pci/controller/pcie-iproc-msi.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/pci/controller/pcie-iproc-msi.c b/drivers/pci/controller/pcie-iproc-msi.c
index eede4e8f3f75..557d93dcb3bc 100644
--- 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);

--
2.30.2