add a char device /dev/hugetlb that behaves similar to /dev/zero,
built on top of internal hugetlbfs mount.
Signed-off-by: Ken Chen <[EMAIL PROTECTED]>
diff -u b/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
--- b/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -795,6 +795,23 @@
return ERR_PTR(error);
}
+int hugetlb_zero_setup(struct file *file, struct vm_area_struct *vma)
+{
+ file = hugetlb_file_setup(vma->vm_end - vma->vm_start, 0);
+ if (IS_ERR(file))
+ return PTR_ERR(file);
+
+ if (vma->vm_file)
+ fput(vma->vm_file);
+ vma->vm_file = file;
+ return hugetlbfs_file_mmap(file, vma);
+}
+
+const struct file_operations hugetlb_dev_fops = {
+ .mmap = hugetlb_zero_setup,
+ .get_unmapped_area = hugetlb_get_unmapped_area,
+};
+
static int __init init_hugetlbfs_fs(void)
{
int error;
diff -u b/include/linux/hugetlb.h b/include/linux/hugetlb.h
--- b/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -162,6 +162,7 @@
}
extern const struct file_operations hugetlbfs_file_operations;
+extern const struct file_operations hugetlb_dev_fops;
extern struct vm_operations_struct hugetlb_vm_ops;
struct file *hugetlb_file_setup(size_t, int);
int hugetlb_get_quota(struct address_space *mapping);
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -27,6 +27,7 @@ #include <linux/backing-dev.h>
#include <linux/bootmem.h>
#include <linux/pipe_fs_i.h>
#include <linux/pfn.h>
+#include <linux/hugetlb.h>
#include <asm/uaccess.h>
#include <asm/io.h>
@@ -939,6 +940,12 @@ #ifdef CONFIG_CRASH_DUMP
filp->f_op = &oldmem_fops;
break;
#endif
+#ifdef CONFIG_HUGETLBFS
+ case 13:
+ printk("open hugetlb dev device\n");
+ filp->f_op = &hugetlb_dev_fops;
+ break;
+#endif
default:
return -ENXIO;
}
@@ -971,6 +978,9 @@ #endif
#ifdef CONFIG_CRASH_DUMP
{12,"oldmem", S_IRUSR | S_IWUSR | S_IRGRP, &oldmem_fops},
#endif
+#ifdef CONFIG_HUGETLBFS
+ {13, "hugetlb",S_IRUGO | S_IWUGO, &hugetlb_dev_fops},
+#endif
};
static struct class *mem_class;
-
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