[PATCH -fixes] mm: Add a call to flush_cache_vmap() in vmap_pfn()

[Alexandre Ghiti]

flush_cache_vmap() must be called after new vmalloc mappings are
installed in the page table in order to allow architectures to make sure
the new mapping is visible.

Fixes: 3e9a9e256b1e ("mm: add a vmap_pfn function")
Reported-by: Dylan Jhong <dylan@xxxxxxxxxxxxx>
Closes: https://lore.kernel.org/linux-riscv/ZMytNY2J8iyjbPPy@xxxxxxxxxxxxxxxxxxxx/
Signed-off-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
---
 mm/vmalloc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 93cf99aba335..228a4a5312f2 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2979,6 +2979,10 @@ void *vmap_pfn(unsigned long *pfns, unsigned int count, pgprot_t prot)
 		free_vm_area(area);
 		return NULL;
 	}
+
+	flush_cache_vmap((unsigned long)area->addr,
+			 (unsigned long)area->addr + count * PAGE_SIZE);
+
 	return area->addr;
 }
 EXPORT_SYMBOL_GPL(vmap_pfn);
-- 
2.39.2