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-rw-r--r--mm/gup.c61
1 files changed, 32 insertions, 29 deletions
diff --git a/mm/gup.c b/mm/gup.c
index ad617e7f22f5..102877ed77a4 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1490,35 +1490,6 @@ int __mm_populate(unsigned long start, unsigned long len, int ignore_errors)
mmap_read_unlock(mm);
return ret; /* 0 or negative error code */
}
-
-/**
- * get_dump_page() - pin user page in memory while writing it to core dump
- * @addr: user address
- *
- * Returns struct page pointer of user page pinned for dump,
- * to be freed afterwards by put_page().
- *
- * Returns NULL on any kind of failure - a hole must then be inserted into
- * the corefile, to preserve alignment with its headers; and also returns
- * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
- * allowing a hole to be left in the corefile to save diskspace.
- *
- * Called without mmap_lock, but after all other threads have been killed.
- */
-#ifdef CONFIG_ELF_CORE
-struct page *get_dump_page(unsigned long addr)
-{
- struct vm_area_struct *vma;
- struct page *page;
-
- if (__get_user_pages(current->mm, addr, 1,
- FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma,
- NULL) < 1)
- return NULL;
- flush_cache_page(vma, addr, page_to_pfn(page));
- return page;
-}
-#endif /* CONFIG_ELF_CORE */
#else /* CONFIG_MMU */
static long __get_user_pages_locked(struct mm_struct *mm, unsigned long start,
unsigned long nr_pages, struct page **pages,
@@ -1564,6 +1535,38 @@ finish_or_fault:
}
#endif /* !CONFIG_MMU */
+/**
+ * get_dump_page() - pin user page in memory while writing it to core dump
+ * @addr: user address
+ *
+ * Returns struct page pointer of user page pinned for dump,
+ * to be freed afterwards by put_page().
+ *
+ * Returns NULL on any kind of failure - a hole must then be inserted into
+ * the corefile, to preserve alignment with its headers; and also returns
+ * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
+ * allowing a hole to be left in the corefile to save diskspace.
+ *
+ * Called without mmap_lock (takes and releases the mmap_lock by itself).
+ */
+#ifdef CONFIG_ELF_CORE
+struct page *get_dump_page(unsigned long addr)
+{
+ struct mm_struct *mm = current->mm;
+ struct page *page;
+ int locked = 1;
+ int ret;
+
+ if (mmap_read_lock_killable(mm))
+ return NULL;
+ ret = __get_user_pages_locked(mm, addr, 1, &page, NULL, &locked,
+ FOLL_FORCE | FOLL_DUMP | FOLL_GET);
+ if (locked)
+ mmap_read_unlock(mm);
+ return (ret == 1) ? page : NULL;
+}
+#endif /* CONFIG_ELF_CORE */
+
#if defined(CONFIG_FS_DAX) || defined (CONFIG_CMA)
static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
{