The mhp layer has alignment restrictions that may cause a failure in
adding a large P2PMEM that has non-aligned number of pages. The new API
pci_p2pdma_align_size will align the P2PMEM size to be inline with the
mhp restrictions.
Signed-off-by: Max Gurtovoy <mgurtovoy@xxxxxxxxxx>
---
drivers/pci/p2pdma.c | 23 +++++++++++++++++++++++
include/linux/pci-p2pdma.h | 5 +++++
2 files changed, 28 insertions(+)
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 196382630363..d232bc4ada2b 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -220,6 +220,29 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size,
}
EXPORT_SYMBOL_GPL(pci_p2pdma_add_resource);
+/**
+ * pci_p2pdma_align_size - align p2p memory size
+ * @size: size of the initial memory to align before adding.
+ *
+ * The size will be aligned according to mph alignment rules. This function
+ * should be called before adding new p2pdma resource since non-aligned memory
+ * will not be added.
+ */
+size_t pci_p2pdma_align_size(size_t size)
+{
+ unsigned int min_align, nr_pages;
+
+ min_align = mhp_get_min_align();
+ nr_pages = size >> PAGE_SHIFT;
+ if (!IS_ALIGNED(nr_pages, min_align)) {
+ nr_pages = ALIGN_DOWN(nr_pages, min_align);
+ size = nr_pages << PAGE_SHIFT;
+ }
+
+ return size;
+}
+EXPORT_SYMBOL_GPL(pci_p2pdma_align_size);
+
/*
* Note this function returns the parent PCI device with a
* reference taken. It is the caller's responsibility to drop
diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h
index 8318a97c9c61..33a8fce52bec 100644
--- a/include/linux/pci-p2pdma.h
+++ b/include/linux/pci-p2pdma.h
@@ -38,6 +38,7 @@ int pci_p2pdma_enable_store(const char *page, struct pci_dev **p2p_dev,
bool *use_p2pdma);
ssize_t pci_p2pdma_enable_show(char *page, struct pci_dev *p2p_dev,
bool use_p2pdma);
+size_t pci_p2pdma_align_size(size_t size);
#else /* CONFIG_PCI_P2PDMA */
static inline int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar,
size_t size, u64 offset)
@@ -105,6 +106,10 @@ static inline ssize_t pci_p2pdma_enable_show(char *page,
{
return sprintf(page, "none\n");
}
+static inline size_t pci_p2pdma_align_size(size_t size)
+{
+ return 0;
+}
#endif /* CONFIG_PCI_P2PDMA */
--
2.18.1
