ANDROID: ashmem: Export is_ashmem_file

Export is_ashmem_file function which will be used
by the minidump module to get ashmem info.

Bug: 193397560
Change-Id: I5b7816ad4775e5cf2c4f41c28b1c8dacc2c85b7e
Signed-off-by: liuhailong <liuhailong@oppo.com>
Signed-off-by: Liujie Xie <xieliujie@oppo.com>
(cherry picked from commit d96c75c8856ddbd5521bbdfbf935da13b5e80a0f)
Signed-off-by: Wentao Guan <guanwentao@uniontech.com>

Author: Liujie Xie

drivers/staging/android/ashmem.c

@@ -937,6 +937,15 @@ static const struct file_operations ashmem_fops = {
 #endif
 };
 
+/*
+ * is_ashmem_file - Check if struct file* is associated with ashmem
+ */
+int is_ashmem_file(struct file *file)
+{
+	return file->f_op == &ashmem_fops;
+}
+EXPORT_SYMBOL_GPL(is_ashmem_file);
+
 static struct miscdevice ashmem_misc = {
 	.minor = MISC_DYNAMIC_MINOR,
 	.name = "ashmem",

drivers/staging/android/ashmem.h

@@ -21,4 +21,6 @@
 #define COMPAT_ASHMEM_SET_PROT_MASK	_IOW(__ASHMEMIOC, 5, unsigned int)
 #endif
 
+int is_ashmem_file(struct file *file);
+
 #endif	/* _LINUX_ASHMEM_H */