From 104640606be0df6bcdb5ec7960a9c3c1278117ae Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Tue, 29 Jan 2013 14:05:58 +0000 Subject: [PATCH] staging: comedi: don't override read/write subdevice if not supported For comedi devices that support asynchronous commands on some of their subdevices, the comedi core creates extra device files for each of those subdevices of the form "/dev/comedi%i_subd%i". These use the same comedi device as the corresponding "/dev/comedi%i" but override the default "read" and "write" subdevice for the device. Currently it overrides both the read and write subdevice, but it only makes sense to override the "read" subdevice if the subdevice supports "read" commands, and to override the "write" subdevice if the subdevice supports "write" commands. In `comedi_alloc_subdevice_minor()`, only set `info->read_subdevice` non-NULL if the subdevice has the `SDF_CMD_READ` flag set, and only set `info->write_subdevice` non-NULL if the subdevice has the `SDF_CMD_WRITE` flag set. (`comedi_read_subdevice(info)` will use the device's default read subdevice if `info->read_subdevice` is NULL. `comedi_write_subdevice(info)` will use the device's default write subdevice if `info->write_subdevice` is NULL. Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/comedi_fops.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index b798e42ee014..fa534fe4864b 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -2358,8 +2358,10 @@ int comedi_alloc_subdevice_minor(struct comedi_device *dev, if (!info) return -ENOMEM; info->device = dev; - info->read_subdevice = s; - info->write_subdevice = s; + if (s->subdev_flags & SDF_CMD_READ) + info->read_subdevice = s; + if (s->subdev_flags & SDF_CMD_WRITE) + info->write_subdevice = s; spin_lock(&comedi_file_info_table_lock); for (i = COMEDI_FIRST_SUBDEVICE_MINOR; i < COMEDI_NUM_MINORS; ++i) { if (comedi_file_info_table[i] == NULL) { -- 2.11.0