Ignore pre-read for character devices

pre_read_file() could ignore a chrdev due to its purpose of providing
unbuffered access to devices not limited to seekable disk devices,
while the purpose of this function (i.e. pre_read= option) is to
lseek(2) the given offset and page cache whatever read via read(2)
which is basically for filesystems and blkdevs.

(This commit directly goes on top of the one before previous one)

Signed-off-by: Tomohiro Kusumi <tkusumi@tuxera.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/filesetup.c b/filesetup.c
index cd486eaa41186ec3668e22b687ec868962b2a571..612e79474dc4b43c0707d6a43dccf3d98a2f9e8f 100644 (file)
--- a/filesetup.c
+++ b/filesetup.c
@@ -239,6 +239,9 @@ static int pre_read_file(struct thread_data *td, struct fio_file *f)
            td_ioengine_flagged(td, FIO_NOIO))
                return 0;
 
+       if (f->filetype == FIO_TYPE_CHAR)
+               return 0;
+
        if (!fio_file_open(f)) {
                if (td->io_ops->open_file(td, f)) {
                        log_err("fio: cannot pre-read, failed to open file\n");