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Message-ID: <4A33A7E2.9020803@gmail.com>
Date: Sat, 13 Jun 2009 15:21:38 +0200
From: Marco <marco.stornelli@...il.com>
To: Linux FS Devel <linux-fsdevel@...r.kernel.org>
CC: Linux Embedded <linux-embedded@...r.kernel.org>,
Linux Kernel <linux-kernel@...r.kernel.org>,
Daniel Walker <dwalker@....ucsc.edu>
Subject: [PATCH 05/14] Pramfs: File operations for files
From: Marco Stornelli <marco.stornelli@...il.com>
File operations for files.
Signed-off-by: Marco Stornelli <marco.stornelli@...il.com>
---
diff -uprN linux-2.6.30-orig/fs/pramfs/file.c linux-2.6.30/fs/pramfs/file.c
--- linux-2.6.30-orig/fs/pramfs/file.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.30/fs/pramfs/file.c 2009-06-13 12:52:56.000000000 +0200
@@ -0,0 +1,141 @@
+/*
+ * FILE NAME fs/pramfs/file.c
+ *
+ * BRIEF DESCRIPTION
+ *
+ * File operations for files.
+ *
+ * Copyright 2009 Marco Stornelli <marco.stornelli@...il.com>
+ * Copyright 2003 Sony Corporation
+ * Copyright 2003 Matsushita Electric Industrial Co., Ltd.
+ * 2003-2004 (c) MontaVista Software, Inc. , Steve Longerbeam
+ * 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/fs.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/uio.h>
+#include <linux/uaccess.h>
+#include "pram_fs.h"
+#include "xip.h"
+
+static int pram_open_file(struct inode *inode, struct file *filp)
+{
+#ifndef CONFIG_PRAMFS_XIP
+ /* Without XIP we force to use Direct IO */
+ filp->f_flags |= O_DIRECT;
+#endif
+ return generic_file_open(inode, filp);
+}
+
+/*
+ * Called when an inode is released. Note that this is different
+ * from pram_open_file: open gets called at every open, but release
+ * gets called only when /all/ the files are closed.
+ */
+static int pram_release_file(struct inode *inode, struct file *filp)
+{
+ return 0;
+}
+
+ssize_t __pram_direct_IO(int rw, struct kiocb *iocb,
+ const struct iovec *iov,
+ loff_t offset, unsigned long nr_segs)
+{
+ struct file *file = iocb->ki_filp;
+ struct inode *inode = file->f_mapping->host;
+ struct super_block *sb = inode->i_sb;
+ int progress = 0;
+ ssize_t retval = 0;
+ struct pram_inode *pi;
+ void *tmp = NULL;
+ unsigned long flags;
+ unsigned long blocknr, blockoff;
+ int num_blocks, blocksize_mask, blocksize, blocksize_bits;
+ char __user *buf = iov->iov_base;
+ size_t length = iov->iov_len;
+
+ flags = 0;
+
+ if (length < 0)
+ return -EINVAL;
+ if ((rw == READ) && (offset + length > inode->i_size))
+ length = inode->i_size - offset;
+ if (!length)
+ goto out;
+
+ blocksize_bits = inode->i_sb->s_blocksize_bits;
+ blocksize = 1 << blocksize_bits;
+ blocksize_mask = blocksize - 1;
+
+ /* find starting block number to access */
+ blocknr = offset >> blocksize_bits;
+ /* find starting offset within starting block */
+ blockoff = offset & blocksize_mask;
+ /* find number of blocks to access */
+ num_blocks = (blockoff + length + blocksize_mask) >> blocksize_bits;
+
+ if (rw == WRITE) {
+ /* prepare a temporary buffer to hold a user data block
+ for writing. */
+ tmp = kmalloc(blocksize, GFP_KERNEL);
+ if (!tmp)
+ return -ENOMEM;
+ /* now allocate the data blocks we'll need */
+ retval = pram_alloc_blocks(inode, blocknr, num_blocks);
+ if (retval)
+ goto fail;
+ }
+
+ pi = pram_get_inode(inode->i_sb, inode->i_ino);
+
+ while (length) {
+ int count;
+ off_t block = pram_find_data_block(inode, blocknr++);
+ u8 *bp = (u8 *)pram_get_block(sb, block);
+ if (!bp)
+ goto fail;
+
+ count = blockoff + length > blocksize ?
+ blocksize - blockoff : length;
+
+ if (rw == READ) {
+ copy_to_user(buf, &bp[blockoff], count);
+ } else {
+ copy_from_user(tmp, buf, count);
+
+ pram_lock_block(inode->i_sb, bp, flags);
+ memcpy(&bp[blockoff], tmp, count);
+ pram_unlock_block(inode->i_sb, bp, flags);
+ }
+
+ progress += count;
+ buf += count;
+ length -= count;
+ blockoff = 0;
+ }
+
+ retval = progress;
+ fail:
+ kfree(tmp);
+ out:
+ return retval;
+}
+
+struct file_operations pram_file_operations = {
+ .llseek = generic_file_llseek,
+ .read = pram_read,
+ .write = pram_write,
+ .aio_read = pram_aio_read,
+ .aio_write = pram_aio_write,
+ .mmap = pram_mmap,
+ .open = pram_open_file,
+ .release = pram_release_file,
+ .fsync = simple_sync_file,
+};
+
+struct inode_operations pram_file_inode_operations = {
+ .truncate = pram_truncate,
+};
--
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