From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
To: nsaenz@kernel.org, jim2101024@gmail.com, f.fainelli@gmail.com,
bcm-kernel-feedback-list@broadcom.com, lorenzo.pieralisi@arm.com,
robh@kernel.org, kw@linux.com, bhelgaas@google.com
Cc: linux-rpi-kernel@lists.infradead.org,
linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org,
linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org,
Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Subject: [PATCH] PCI: brcmstb: Declare a bitmap as a bitmap, not as a plain 'unsigned long'
Date: Sun, 7 Nov 2021 09:32:58 +0100 [thread overview]
Message-ID: <e6d9da2112aab2939d1507b90962d07bfd735b4c.1636273671.git.christophe.jaillet@wanadoo.fr> (raw)
The 'used' field of 'struct brcm_msi' is used as a bitmap. So it should
be declared as so (i.e. unsigned long *).
This fixes an harmless Coverity warning about array vs singleton usage.
This bitmap can be BRCM_INT_PCI_MSI_LEGACY_NR or BRCM_INT_PCI_MSI_NR long.
So, while at it, document it, should it help someone in the future.
Addresses-Coverity: "Out-of-bounds access (ARRAY_VS_SINGLETON)"
Suggested-by: Krzysztof Wilczynski <kw@linux.com>
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
The BUILD_BUG_ON is surely a bit to much of paranoia :)
I'm also not really pleased about the layout of the DECLARE_BITMAP. This
looks odd, but I couldn't find something nicer :(
---
drivers/pci/controller/pcie-brcmstb.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 1fc7bd49a7ad..15d394ac7478 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -266,8 +266,9 @@ struct brcm_msi {
struct mutex lock; /* guards the alloc/free operations */
u64 target_addr;
int irq;
- /* used indicates which MSI interrupts have been alloc'd */
- unsigned long used;
+ /* Used indicates which MSI interrupts have been alloc'd. 'nr' bellow is
+ the real size of the bitmap. It depends on the chip. */
+ DECLARE_BITMAP (used, BRCM_INT_PCI_MSI_NR);
bool legacy;
/* Some chips have MSIs in bits [31..24] of a shared register. */
int legacy_shift;
@@ -534,7 +535,7 @@ static int brcm_msi_alloc(struct brcm_msi *msi)
int hwirq;
mutex_lock(&msi->lock);
- hwirq = bitmap_find_free_region(&msi->used, msi->nr, 0);
+ hwirq = bitmap_find_free_region(msi->used, msi->nr, 0);
mutex_unlock(&msi->lock);
return hwirq;
@@ -543,7 +544,7 @@ static int brcm_msi_alloc(struct brcm_msi *msi)
static void brcm_msi_free(struct brcm_msi *msi, unsigned long hwirq)
{
mutex_lock(&msi->lock);
- bitmap_release_region(&msi->used, hwirq, 0);
+ bitmap_release_region(msi->used, hwirq, 0);
mutex_unlock(&msi->lock);
}
@@ -661,6 +662,12 @@ static int brcm_pcie_enable_msi(struct brcm_pcie *pcie)
msi->irq = irq;
msi->legacy = pcie->hw_rev < BRCM_PCIE_HW_REV_33;
+ /*
+ * Sanity check to make sure that the 'used' bitmap in struct brcm_msi
+ * is large enough.
+ */
+ BUILD_BUG_ON(BRCM_INT_PCI_MSI_LEGACY_NR > BRCM_INT_PCI_MSI_NR);
+
if (msi->legacy) {
msi->intr_base = msi->base + PCIE_INTR2_CPU_BASE;
msi->nr = BRCM_INT_PCI_MSI_LEGACY_NR;
--
2.30.2
next reply other threads:[~2021-11-07 8:33 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-07 8:32 Christophe JAILLET [this message]
2021-11-08 1:34 ` [PATCH] PCI: brcmstb: Declare a bitmap as a bitmap, not as a plain 'unsigned long' Krzysztof Wilczyński
2021-11-08 16:28 ` Florian Fainelli
2021-11-08 19:51 ` Christophe JAILLET
2021-11-08 23:30 ` Krzysztof Wilczyński
2021-11-08 23:45 ` Florian Fainelli
2021-11-08 23:55 ` Krzysztof Wilczyński
2021-11-08 23:44 ` Florian Fainelli
2021-11-29 13:11 ` Lorenzo Pieralisi
2021-11-30 17:04 ` Bjorn Helgaas
2021-12-03 11:02 ` Dan Carpenter
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