This was copied from fs/libfs.c
Signed-off-by: Hauke Mehrtens <hauke@xxxxxxxxxx>
---
compat/compat-2.6.35.c | 34 ++++++++++++++++++++++++++++++++++
include/linux/compat-2.6.35.h | 3 +++
2 files changed, 37 insertions(+)
diff --git a/compat/compat-2.6.35.c b/compat/compat-2.6.35.c
index 0fc0db2..422487c 100644
--- a/compat/compat-2.6.35.c
+++ b/compat/compat-2.6.35.c
@@ -89,3 +89,37 @@ loff_t noop_llseek(struct file *file, loff_t offset, int origin)
}
EXPORT_SYMBOL_GPL(noop_llseek);
+/**
+ * simple_write_to_buffer - copy data from user space to the buffer
+ * @to: the buffer to write to
+ * @available: the size of the buffer
+ * @ppos: the current position in the buffer
+ * @from: the user space buffer to read from
+ * @count: the maximum number of bytes to read
+ *
+ * The simple_write_to_buffer() function reads up to @count bytes from the user
+ * space address starting at @from into the buffer @to at offset @ppos.
+ *
+ * On success, the number of bytes written is returned and the offset @ppos is
+ * advanced by this number, or negative value is returned on error.
+ **/
+ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
+ const void __user *from, size_t count)
+{
+ loff_t pos = *ppos;
+ size_t res;
+
+ if (pos < 0)
+ return -EINVAL;
+ if (pos >= available || !count)
+ return 0;
+ if (count > available - pos)
+ count = available - pos;
+ res = copy_from_user(to + pos, from, count);
+ if (res == count)
+ return -EFAULT;
+ count -= res;
+ *ppos = pos + count;
+ return count;
+}
+EXPORT_SYMBOL(simple_write_to_buffer);
diff --git a/include/linux/compat-2.6.35.h b/include/linux/compat-2.6.35.h
index b06638a..82b4dea 100644
--- a/include/linux/compat-2.6.35.h
+++ b/include/linux/compat-2.6.35.h
@@ -88,6 +88,9 @@ usb_pipe_endpoint(struct usb_device *dev, unsigned int pipe)
return eps[usb_pipeendpoint(pipe)];
}
+extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
+ const void __user *from, size_t count);
+
#endif /* (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,35)) */
#endif /* LINUX_26_35_COMPAT_H */
--
1.7.10.4
--
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