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Date: Sun, 10 Jun 2012 11:15:29 +0200
From: Marco Stornelli <marco.stornelli@...il.com>
To: Linux FS Devel <linux-fsdevel@...r.kernel.org>
CC: Linux Kernel <linux-kernel@...r.kernel.org>
Subject: [PATCH 10/17] pramfs: xip support
From: Marco Stornelli <marco.stornelli@...il.com>
XIP operations.
Signed-off-by: Marco Stornelli <marco.stornelli@...il.com>
---
diff -Nurp linux-3.5-rc2-orig/fs/pramfs/xip.c linux-3.5-rc2/fs/pramfs/xip.c
--- linux-3.5-rc2-orig/fs/pramfs/xip.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-3.5-rc2/fs/pramfs/xip.c 2012-06-10 10:08:28.000000000 +0200
@@ -0,0 +1,117 @@
+/*
+ * BRIEF DESCRIPTION
+ *
+ * XIP operations.
+ *
+ * Copyright 2009-2011 Marco Stornelli <marco.stornelli@...il.com>
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/mm.h>
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include "pram.h"
+#include "xip.h"
+
+/*
+ * Wrappers. We need to use the rcu read lock to avoid
+ * concurrent truncate operation. No problem for write because we held
+ * i_mutex.
+ */
+ssize_t pram_xip_file_read(struct file *filp, char __user *buf,
+ size_t len, loff_t *ppos)
+{
+ ssize_t res;
+ rcu_read_lock();
+ res = xip_file_read(filp, buf, len, ppos);
+ rcu_read_unlock();
+ return res;
+}
+
+static int pram_xip_file_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ int ret = 0;
+ rcu_read_lock();
+ ret = xip_file_fault(vma, vmf);
+ rcu_read_unlock();
+ return ret;
+}
+
+static const struct vm_operations_struct pram_xip_vm_ops = {
+ .fault = pram_xip_file_fault,
+};
+
+int pram_xip_file_mmap(struct file * file, struct vm_area_struct * vma)
+{
+ BUG_ON(!file->f_mapping->a_ops->get_xip_mem);
+
+ file_accessed(file);
+ vma->vm_ops = &pram_xip_vm_ops;
+ vma->vm_flags |= VM_CAN_NONLINEAR | VM_MIXEDMAP;
+ return 0;
+}
+
+static int pram_find_and_alloc_blocks(struct inode *inode, sector_t iblock,
+ sector_t *data_block, int create)
+{
+ int err = -EIO;
+ u64 block;
+
+ block = pram_find_data_block(inode, iblock);
+
+ if (!block) {
+ if (!create) {
+ err = -ENODATA;
+ goto err;
+ }
+
+ err = pram_alloc_blocks(inode, iblock, 1);
+ if (err)
+ goto err;
+
+ block = pram_find_data_block(inode, iblock);
+ if (!block) {
+ err = -ENODATA;
+ goto err;
+ }
+ }
+
+ *data_block = block;
+ err = 0;
+
+ err:
+ return err;
+}
+
+static inline int __pram_get_block(struct inode *inode, pgoff_t pgoff,
+ int create, sector_t *result)
+{
+ int rc = 0;
+
+ rc = pram_find_and_alloc_blocks(inode, (sector_t)pgoff, result, create);
+
+ if (rc == -ENODATA)
+ BUG_ON(create);
+
+ return rc;
+}
+
+int pram_get_xip_mem(struct address_space *mapping, pgoff_t pgoff, int create,
+ void **kmem, unsigned long *pfn)
+{
+ int rc;
+ sector_t block = 0;
+
+ /* first, retrieve the block */
+ rc = __pram_get_block(mapping->host, pgoff, create, &block);
+ if (rc)
+ goto exit;
+
+ *kmem = pram_get_block(mapping->host->i_sb, block);
+ *pfn = pram_get_pfn(mapping->host->i_sb, block);
+
+exit:
+ return rc;
+}
diff -Nurp linux-3.5-rc2-orig/fs/pramfs/xip.h linux-3.5-rc2/fs/pramfs/xip.h
--- linux-3.5-rc2-orig/fs/pramfs/xip.h 1970-01-01 01:00:00.000000000 +0100
+++ linux-3.5-rc2/fs/pramfs/xip.h 2012-06-10 10:08:28.000000000 +0200
@@ -0,0 +1,33 @@
+/*
+ * BRIEF DESCRIPTION
+ *
+ * XIP operations.
+ *
+ * Copyright 2009-2011 Marco Stornelli <marco.stornelli@...il.com>
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#ifdef CONFIG_PRAMFS_XIP
+int pram_get_xip_mem(struct address_space *, pgoff_t, int, void **,
+ unsigned long *);
+ssize_t pram_xip_file_read(struct file *filp, char __user *buf,
+ size_t len, loff_t *ppos);
+int pram_xip_file_mmap(struct file * file, struct vm_area_struct * vma);
+static inline int pram_use_xip(struct super_block *sb)
+{
+ struct pram_sb_info *sbi = PRAM_SB(sb);
+ return sbi->s_mount_opt & PRAM_MOUNT_XIP;
+}
+#define mapping_is_xip(map) (map->a_ops->get_xip_mem)
+
+#else
+
+#define mapping_is_xip(map) 0
+#define pram_use_xip(sb) 0
+#define pram_get_xip_mem NULL
+#define pram_xip_file_read NULL
+#define pram_xip_file_mmap NULL
+
+#endif
diff -Nurp linux-3.5-rc2-orig/mm/filemap_xip.c linux-3.5-rc2/mm/filemap_xip.c
--- linux-3.5-rc2-orig/mm/filemap_xip.c 2012-06-09 03:40:09.000000000 +0200
+++ linux-3.5-rc2/mm/filemap_xip.c 2012-06-10 10:08:27.000000000 +0200
@@ -218,7 +218,7 @@ retry:
*
* This function is derived from filemap_fault, but used for execute in place
*/
-static int xip_file_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+int xip_file_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct file *file = vma->vm_file;
struct address_space *mapping = file->f_mapping;
@@ -302,6 +302,7 @@ out:
}
}
+EXPORT_SYMBOL_GPL(xip_file_fault);
static const struct vm_operations_struct xip_file_vm_ops = {
.fault = xip_file_fault,
};
--
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