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-rw-r--r--fs/configfs/file.c29
1 files changed, 22 insertions, 7 deletions
diff --git a/fs/configfs/file.c b/fs/configfs/file.c
index 2f63bf3a7325..5a0be9985bae 100644
--- a/fs/configfs/file.c
+++ b/fs/configfs/file.c
@@ -91,7 +91,10 @@ static ssize_t configfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
}
pr_debug("%s: count = %zd, pos = %lld, buf = %s\n",
__func__, iov_iter_count(to), iocb->ki_pos, buffer->page);
- retval = copy_to_iter(buffer->page, buffer->count, to);
+ if (iocb->ki_pos >= buffer->count)
+ goto out;
+ retval = copy_to_iter(buffer->page + iocb->ki_pos,
+ buffer->count - iocb->ki_pos, to);
iocb->ki_pos += retval;
if (retval == 0)
retval = -EFAULT;
@@ -162,7 +165,10 @@ static ssize_t configfs_bin_read_iter(struct kiocb *iocb, struct iov_iter *to)
buffer->needs_read_fill = 0;
}
- retval = copy_to_iter(buffer->bin_buffer, buffer->bin_buffer_size, to);
+ if (iocb->ki_pos >= buffer->bin_buffer_size)
+ goto out;
+ retval = copy_to_iter(buffer->bin_buffer + iocb->ki_pos,
+ buffer->bin_buffer_size - iocb->ki_pos, to);
iocb->ki_pos += retval;
if (retval == 0)
retval = -EFAULT;
@@ -171,21 +177,28 @@ out:
return retval;
}
-static int fill_write_buffer(struct configfs_buffer *buffer,
+/* Fill [buffer, buffer + pos) with data coming from @from. */
+static int fill_write_buffer(struct configfs_buffer *buffer, loff_t pos,
struct iov_iter *from)
{
+ loff_t to_copy;
int copied;
+ u8 *to;
if (!buffer->page)
buffer->page = (char *)__get_free_pages(GFP_KERNEL, 0);
if (!buffer->page)
return -ENOMEM;
- copied = copy_from_iter(buffer->page, SIMPLE_ATTR_SIZE - 1, from);
+ to_copy = SIMPLE_ATTR_SIZE - 1 - pos;
+ if (to_copy <= 0)
+ return 0;
+ to = buffer->page + pos;
+ copied = copy_from_iter(to, to_copy, from);
buffer->needs_read_fill = 1;
/* if buf is assumed to contain a string, terminate it by \0,
* so e.g. sscanf() can scan the string easily */
- buffer->page[copied] = 0;
+ to[copied] = 0;
return copied ? : -EFAULT;
}
@@ -217,7 +230,7 @@ static ssize_t configfs_write_iter(struct kiocb *iocb, struct iov_iter *from)
ssize_t len;
mutex_lock(&buffer->mutex);
- len = fill_write_buffer(buffer, from);
+ len = fill_write_buffer(buffer, iocb->ki_pos, from);
if (len > 0)
len = flush_write_buffer(file, buffer, len);
if (len > 0)
@@ -272,7 +285,9 @@ static ssize_t configfs_bin_write_iter(struct kiocb *iocb,
buffer->bin_buffer_size = end_offset;
}
- len = copy_from_iter(buffer->bin_buffer, buffer->bin_buffer_size, from);
+ len = copy_from_iter(buffer->bin_buffer + iocb->ki_pos,
+ buffer->bin_buffer_size - iocb->ki_pos, from);
+ iocb->ki_pos += len;
out:
mutex_unlock(&buffer->mutex);
return len ? : -EFAULT;