[PATCHv2] PCI: Add pci_iounmap

From: George Cherian
Date: Thu Aug 20 2020 - 01:03:28 EST


In case if any architecture selects CONFIG_GENERIC_PCI_IOMAP and not
CONFIG_GENERIC_IOMAP, then the pci_iounmap function is reduced to a NULL
function. Due to this the managed release variants or even the explicit
pci_iounmap calls doesn't really remove the mappings.

This issue is seen on an arm64 based system. arm64 by default selects
only CONFIG_GENERIC_PCI_IOMAP and not CONFIG_GENERIC_IOMAP from this
'commit cb61f6769b88 ("ARM64: use GENERIC_PCI_IOMAP")'

Simple bind/unbind test of any pci driver using pcim_iomap/pci_iomap,
would lead to the following error message after long hour tests

"allocation failed: out of vmalloc space - use vmalloc=<size> to
increase size."

Signed-off-by: George Cherian <george.cherian@xxxxxxxxxxx>
---
* Changes from v1
- Fix the 0-day compilation error.
- Mark the lib/iomap pci_iounmap call as weak incase
if any architecture have there own implementation.

include/asm-generic/io.h | 4 ++++
lib/pci_iomap.c | 10 ++++++++++
2 files changed, 14 insertions(+)

diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index dabf8cb7203b..5986b37226b7 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -915,12 +915,16 @@ static inline void iowrite64_rep(volatile void __iomem *addr,
struct pci_dev;
extern void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long max);

+#ifdef CONFIG_GENERIC_PCI_IOMAP
+extern void pci_iounmap(struct pci_dev *dev, void __iomem *p);
+#else
#ifndef pci_iounmap
#define pci_iounmap pci_iounmap
static inline void pci_iounmap(struct pci_dev *dev, void __iomem *p)
{
}
#endif
+#endif /* CONFIG_GENERIC_PCI_IOMAP */
#endif /* CONFIG_GENERIC_IOMAP */

/*
diff --git a/lib/pci_iomap.c b/lib/pci_iomap.c
index 2d3eb1cb73b8..ecd1eb3f6c25 100644
--- a/lib/pci_iomap.c
+++ b/lib/pci_iomap.c
@@ -134,4 +134,14 @@ void __iomem *pci_iomap_wc(struct pci_dev *dev, int bar, unsigned long maxlen)
return pci_iomap_wc_range(dev, bar, 0, maxlen);
}
EXPORT_SYMBOL_GPL(pci_iomap_wc);
+
+#ifndef CONFIG_GENERIC_IOMAP
+#define pci_iounmap pci_iounmap
+void __weak pci_iounmap(struct pci_dev *dev, void __iomem *addr);
+void __weak pci_iounmap(struct pci_dev *dev, void __iomem *addr)
+{
+ iounmap(addr);
+}
+EXPORT_SYMBOL(pci_iounmap);
+#endif
#endif /* CONFIG_PCI */
--
2.25.1