Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6

[pandora-kernel.git] / fs / configfs / file.c

diff --git a/fs/configfs/file.c b/fs/configfs/file.c
index d98be5e..397cb50 100644 (file)
--- a/fs/configfs/file.c
+++ b/fs/configfs/file.c
@@ -27,19 +27,26 @@
 #include <linux/fs.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/mutex.h>
 #include <asm/uaccess.h>
-#include <asm/semaphore.h>
 
 #include <linux/configfs.h>
 #include "configfs_internal.h"
 
+/*
+ * A simple attribute can only be 4096 characters.  Why 4k?  Because the
+ * original code limited it to PAGE_SIZE.  That's a bad idea, though,
+ * because an attribute of 16k on ia64 won't work on x86.  So we limit to
+ * 4k, our minimum common page size.
+ */
+#define SIMPLE_ATTR_SIZE 4096
 
 struct configfs_buffer {
        size_t                  count;
        loff_t                  pos;
        char                    * page;
        struct configfs_item_operations * ops;
-       struct semaphore        sem;
+       struct mutex            mutex;
        int                     needs_read_fill;
 };
 
@@ -69,7 +76,7 @@ static int fill_read_buffer(struct dentry * dentry, struct configfs_buffer * buf
 
        count = ops->show_attribute(item,attr,buffer->page);
        buffer->needs_read_fill = 0;
-       BUG_ON(count > (ssize_t)PAGE_SIZE);
+       BUG_ON(count > (ssize_t)SIMPLE_ATTR_SIZE);
        if (count >= 0)
                buffer->count = count;
        else
@@ -77,36 +84,6 @@ static int fill_read_buffer(struct dentry * dentry, struct configfs_buffer * buf
        return ret;
 }
 
-
-/**
- *     flush_read_buffer - push buffer to userspace.
- *     @buffer:        data buffer for file.
- *     @userbuf:       user-passed buffer.
- *     @count:         number of bytes requested.
- *     @ppos:          file position.
- *
- *     Copy the buffer we filled in fill_read_buffer() to userspace.
- *     This is done at the reader's leisure, copying and advancing
- *     the amount they specify each time.
- *     This may be called continuously until the buffer is empty.
- */
-static int flush_read_buffer(struct configfs_buffer * buffer, char __user * buf,
-                            size_t count, loff_t * ppos)
-{
-       int error;
-
-       if (*ppos > buffer->count)
-               return 0;
-
-       if (count > (buffer->count - *ppos))
-               count = buffer->count - *ppos;
-
-       error = copy_to_user(buf,buffer->page + *ppos,count);
-       if (!error)
-               *ppos += count;
-       return error ? -EFAULT : count;
-}
-
 /**
  *     configfs_read_file - read an attribute.
  *     @file:  file pointer.
@@ -132,16 +109,17 @@ configfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *pp
        struct configfs_buffer * buffer = file->private_data;
        ssize_t retval = 0;
 
-       down(&buffer->sem);
+       mutex_lock(&buffer->mutex);
        if (buffer->needs_read_fill) {
                if ((retval = fill_read_buffer(file->f_path.dentry,buffer)))
                        goto out;
        }
        pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n",
                 __FUNCTION__, count, *ppos, buffer->page);
-       retval = flush_read_buffer(buffer,buf,count,ppos);
+       retval = simple_read_from_buffer(buf, count, ppos, buffer->page,
+                                        buffer->count);
 out:
-       up(&buffer->sem);
+       mutex_unlock(&buffer->mutex);
        return retval;
 }
 
@@ -166,8 +144,8 @@ fill_write_buffer(struct configfs_buffer * buffer, const char __user * buf, size
        if (!buffer->page)
                return -ENOMEM;
 
-       if (count >= PAGE_SIZE)
-               count = PAGE_SIZE - 1;
+       if (count >= SIMPLE_ATTR_SIZE)
+               count = SIMPLE_ATTR_SIZE - 1;
        error = copy_from_user(buffer->page,buf,count);
        buffer->needs_read_fill = 1;
        /* if buf is assumed to contain a string, terminate it by \0,
@@ -222,13 +200,13 @@ configfs_write_file(struct file *file, const char __user *buf, size_t count, lof
        struct configfs_buffer * buffer = file->private_data;
        ssize_t len;
 
-       down(&buffer->sem);
+       mutex_lock(&buffer->mutex);
        len = fill_write_buffer(buffer, buf, count);
        if (len > 0)
                len = flush_write_buffer(file->f_path.dentry, buffer, count);
        if (len > 0)
                *ppos += len;
-       up(&buffer->sem);
+       mutex_unlock(&buffer->mutex);
        return len;
 }
 
@@ -282,7 +260,7 @@ static int check_perm(struct inode * inode, struct file * file)
                error = -ENOMEM;
                goto Enomem;
        }
-       init_MUTEX(&buffer->sem);
+       mutex_init(&buffer->mutex);
        buffer->needs_read_fill = 1;
        buffer->ops = ops;
        file->private_data = buffer;
@@ -321,6 +299,7 @@ static int configfs_release(struct inode * inode, struct file * filp)
        if (buffer) {
                if (buffer->page)
                        free_page((unsigned long)buffer->page);
+               mutex_destroy(&buffer->mutex);
                kfree(buffer);
        }
        return 0;
@@ -341,7 +320,7 @@ int configfs_add_file(struct dentry * dir, const struct configfs_attribute * att
        umode_t mode = (attr->ca_mode & S_IALLUGO) | S_IFREG;
        int error = 0;
 
-       mutex_lock(&dir->d_inode->i_mutex);
+       mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_NORMAL);
        error = configfs_make_dirent(parent_sd, NULL, (void *) attr, mode, type);
        mutex_unlock(&dir->d_inode->i_mutex);