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From:   Sandor Bodo-Merle <sbodomerle@gmail.com>
To:     Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Rob Herring <robh@kernel.org>,
        =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= <kw@linux.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Ray Jui <rjui@broadcom.com>,
        Scott Branden <sbranden@broadcom.com>,
        bcm-kernel-feedback-list@broadcom.com,
        Sandor Bodo-Merle <sbodomerle@gmail.com>,
        linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
Cc:     =?UTF-8?q?Pali=20Roh=C3=A1r?= <pali@kernel.org>
Subject: [PATCH 1/2] PCI: iproc: fix the base vector number allocation for multi-MSI
Date:   Sun,  6 Jun 2021 14:30:43 +0200
Message-Id: <20210606123044.31250-1-sbodomerle@gmail.com>
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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.

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>
---
 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);
 
-- 
2.31.0