diff options
| -rw-r--r-- | fs/configfs/file.c | 29 |
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; |