Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs (7d8761ba) · Commits · 戴 / test

fs/seq_file.c

+27 −30

Original line number	Diff line number	Diff line
		@@ -168,12 +168,14 @@ EXPORT_SYMBOL(seq_read);
		ssize_t seq_read_iter(struct kiocb iocb, struct iov_iter iter)
		{
		struct seq_file *m = iocb->ki_filp->private_data;
		size_t size = iov_iter_count(iter);
		size_t copied = 0;
		size_t n;
		void *p;
		int err = 0;

		if (!iov_iter_count(iter))
		return 0;

		mutex_lock(&m->lock);

		/*
		@@ -206,36 +208,34 @@ ssize_t seq_read_iter(struct kiocb iocb, struct iov_iter iter)
		if (!m->buf)
		goto Enomem;
		}
		/* if not empty - flush it first */
		// something left in the buffer - copy it out first
		if (m->count) {
		n = min(m->count, size);
		if (copy_to_iter(m->buf + m->from, n, iter) != n)
		goto Efault;
		n = copy_to_iter(m->buf + m->from, m->count, iter);
		m->count -= n;
		m->from += n;
		size -= n;
		copied += n;
		if (!size)
		if (m->count) // hadn't managed to copy everything
		goto Done;
		}
		/* we need at least one record in buffer */
		// get a non-empty record in the buffer
		m->from = 0;
		p = m->op->start(m, &m->index);
		while (1) {
		err = PTR_ERR(p);
		if (!p \|\| IS_ERR(p))
		if (!p \|\| IS_ERR(p)) // EOF or an error
		break;
		err = m->op->show(m, p);
		if (err < 0)
		if (err < 0) // hard error
		break;
		if (unlikely(err))
		if (unlikely(err)) // ->show() says "skip it"
		m->count = 0;
		if (unlikely(!m->count)) {
		if (unlikely(!m->count)) { // empty record
		p = m->op->next(m, p, &m->index);
		continue;
		}
		if (m->count < m->size)
		if (!seq_has_overflowed(m)) // got it
		goto Fill;
		// need a bigger buffer
		m->op->stop(m, p);
		kvfree(m->buf);
		m->count = 0;
		@@ -244,11 +244,14 @@ ssize_t seq_read_iter(struct kiocb iocb, struct iov_iter iter)
		goto Enomem;
		p = m->op->start(m, &m->index);
		}
		// EOF or an error
		m->op->stop(m, p);
		m->count = 0;
		goto Done;
		Fill:
		/* they want more? let's try to get some more */
		// one non-empty record is in the buffer; if they want more,
		// try to fit more in, but in any case we need to advance
		// the iterator once for every record shown.
		while (1) {
		size_t offs = m->count;
		loff_t pos = m->index;
		@@ -259,30 +262,27 @@ Fill:
		m->op->next);
		m->index++;
		}
		if (!p \|\| IS_ERR(p)) {
		err = PTR_ERR(p);
		if (!p \|\| IS_ERR(p)) // no next record for us
		break;
		}
		if (m->count >= size)
		if (m->count >= iov_iter_count(iter))
		break;
		err = m->op->show(m, p);
		if (seq_has_overflowed(m) \|\| err) {
		if (err > 0) { // ->show() says "skip it"
		m->count = offs;
		} else if (err \|\| seq_has_overflowed(m)) {
		m->count = offs;
		if (likely(err <= 0))
		break;
		}
		}
		m->op->stop(m, p);
		n = min(m->count, size);
		if (copy_to_iter(m->buf, n, iter) != n)
		goto Efault;
		n = copy_to_iter(m->buf, m->count, iter);
		copied += n;
		m->count -= n;
		m->from = n;
		Done:
		if (!copied)
		copied = err;
		else {
		if (unlikely(!copied)) {
		copied = m->count ? -EFAULT : err;
		} else {
		iocb->ki_pos += copied;
		m->read_pos += copied;
		}
		@@ -291,9 +291,6 @@ Done:
		Enomem:
		err = -ENOMEM;
		goto Done;
		Efault:
		err = -EFAULT;
		goto Done;
		}
		EXPORT_SYMBOL(seq_read_iter);

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