diff options
| -rw-r--r-- | block/fops.c | 33 |
1 files changed, 19 insertions, 14 deletions
diff --git a/block/fops.c b/block/fops.c index 26bf15c770d2..4f59e0f5bf30 100644 --- a/block/fops.c +++ b/block/fops.c @@ -566,34 +566,37 @@ static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) { struct block_device *bdev = iocb->ki_filp->private_data; loff_t size = bdev_nr_bytes(bdev); - size_t count = iov_iter_count(to); loff_t pos = iocb->ki_pos; size_t shorted = 0; ssize_t ret = 0; + size_t count; - if (unlikely(pos + count > size)) { + if (unlikely(pos + iov_iter_count(to) > size)) { if (pos >= size) return 0; size -= pos; - if (count > size) { - shorted = count - size; - iov_iter_truncate(to, size); - } + shorted = iov_iter_count(to) - size; + iov_iter_truncate(to, size); } + count = iov_iter_count(to); + if (!count) + goto reexpand; /* skip atime */ + if (iocb->ki_flags & IOCB_DIRECT) { struct address_space *mapping = iocb->ki_filp->f_mapping; if (iocb->ki_flags & IOCB_NOWAIT) { - if (filemap_range_needs_writeback(mapping, iocb->ki_pos, - iocb->ki_pos + count - 1)) - return -EAGAIN; + if (filemap_range_needs_writeback(mapping, pos, + pos + count - 1)) { + ret = -EAGAIN; + goto reexpand; + } } else { - ret = filemap_write_and_wait_range(mapping, - iocb->ki_pos, - iocb->ki_pos + count - 1); + ret = filemap_write_and_wait_range(mapping, pos, + pos + count - 1); if (ret < 0) - return ret; + goto reexpand; } file_accessed(iocb->ki_filp); @@ -603,12 +606,14 @@ static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) iocb->ki_pos += ret; count -= ret; } + iov_iter_revert(to, count - iov_iter_count(to)); if (ret < 0 || !count) - return ret; + goto reexpand; } ret = filemap_read(iocb, to, ret); +reexpand: if (unlikely(shorted)) iov_iter_reexpand(to, iov_iter_count(to) + shorted); return ret; |