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-rw-r--r--mm/memory.c81
-rw-r--r--mm/nommu.c14
2 files changed, 95 insertions, 0 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 9b68a72f8c17..96f1d473c89a 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1527,6 +1527,87 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
}
EXPORT_SYMBOL(vm_insert_page);
+/*
+ * __vm_map_pages - maps range of kernel pages into user vma
+ * @vma: user vma to map to
+ * @pages: pointer to array of source kernel pages
+ * @num: number of pages in page array
+ * @offset: user's requested vm_pgoff
+ *
+ * This allows drivers to map range of kernel pages into a user vma.
+ *
+ * Return: 0 on success and error code otherwise.
+ */
+static int __vm_map_pages(struct vm_area_struct *vma, struct page **pages,
+ unsigned long num, unsigned long offset)
+{
+ unsigned long count = vma_pages(vma);
+ unsigned long uaddr = vma->vm_start;
+ int ret, i;
+
+ /* Fail if the user requested offset is beyond the end of the object */
+ if (offset > num)
+ return -ENXIO;
+
+ /* Fail if the user requested size exceeds available object size */
+ if (count > num - offset)
+ return -ENXIO;
+
+ for (i = 0; i < count; i++) {
+ ret = vm_insert_page(vma, uaddr, pages[offset + i]);
+ if (ret < 0)
+ return ret;
+ uaddr += PAGE_SIZE;
+ }
+
+ return 0;
+}
+
+/**
+ * vm_map_pages - maps range of kernel pages starts with non zero offset
+ * @vma: user vma to map to
+ * @pages: pointer to array of source kernel pages
+ * @num: number of pages in page array
+ *
+ * Maps an object consisting of @num pages, catering for the user's
+ * requested vm_pgoff
+ *
+ * If we fail to insert any page into the vma, the function will return
+ * immediately leaving any previously inserted pages present. Callers
+ * from the mmap handler may immediately return the error as their caller
+ * will destroy the vma, removing any successfully inserted pages. Other
+ * callers should make their own arrangements for calling unmap_region().
+ *
+ * Context: Process context. Called by mmap handlers.
+ * Return: 0 on success and error code otherwise.
+ */
+int vm_map_pages(struct vm_area_struct *vma, struct page **pages,
+ unsigned long num)
+{
+ return __vm_map_pages(vma, pages, num, vma->vm_pgoff);
+}
+EXPORT_SYMBOL(vm_map_pages);
+
+/**
+ * vm_map_pages_zero - map range of kernel pages starts with zero offset
+ * @vma: user vma to map to
+ * @pages: pointer to array of source kernel pages
+ * @num: number of pages in page array
+ *
+ * Similar to vm_map_pages(), except that it explicitly sets the offset
+ * to 0. This function is intended for the drivers that did not consider
+ * vm_pgoff.
+ *
+ * Context: Process context. Called by mmap handlers.
+ * Return: 0 on success and error code otherwise.
+ */
+int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages,
+ unsigned long num)
+{
+ return __vm_map_pages(vma, pages, num, 0);
+}
+EXPORT_SYMBOL(vm_map_pages_zero);
+
static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr,
pfn_t pfn, pgprot_t prot, bool mkwrite)
{
diff --git a/mm/nommu.c b/mm/nommu.c
index 749276beb109..b492fd1fcf9f 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -473,6 +473,20 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
}
EXPORT_SYMBOL(vm_insert_page);
+int vm_map_pages(struct vm_area_struct *vma, struct page **pages,
+ unsigned long num)
+{
+ return -EINVAL;
+}
+EXPORT_SYMBOL(vm_map_pages);
+
+int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages,
+ unsigned long num)
+{
+ return -EINVAL;
+}
+EXPORT_SYMBOL(vm_map_pages_zero);
+
/*
* sys_brk() for the most part doesn't need the global kernel
* lock, except when an application is doing something nasty