`comedi_is_subdevice_in_error()` is only used by `comedi_read()` and
`comedi_write()` and is only called (soon) after
`comedi_is_subdevice_running()` returns `false` (with extra conditions
in the case of `comedi_write()`). `comedi_is_subdevice_running()` and
`comedi_get_subdevice_runflags()` both call
`comedi_get_subdevice_runflags()` which uses the subdevice's spin-lock.
Eliminate one use of the subdevice's spin-lock in `comedi_read()` and
`comedi_write()` by calling `comedi_get_subdevice_runflags()` and
checking the runflags directly. Add a couple of inline functions to
check the runflags: `comedi_is_runflags_running()` and
`comedi_is_runflags_in_error()`. These do the same test on runflags as
`comedi_is_subdevice_running()` and `comedi_is_subdevice_in_error()` but
get passed the runflags value directly.
`comedi_is_subdevice_in_error()` is no longer used, so remove it.
Signed-off-by: Ian Abbott <abbo...@mev.co.uk>
---
drivers/staging/comedi/comedi_fops.c | 32 ++++++++++++++++++++------------
1 file changed, 20 insertions(+), 12 deletions(-)
diff --git a/drivers/staging/comedi/comedi_fops.c
b/drivers/staging/comedi/comedi_fops.c
index 2b75b7a1..17ac285 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -623,6 +623,16 @@ static unsigned comedi_get_subdevice_runflags(struct
comedi_subdevice *s)
return runflags;
}
+static bool comedi_is_runflags_running(unsigned runflags)
+{
+ return runflags & COMEDI_SRF_RUNNING;
+}
+
+static bool comedi_is_runflags_in_error(unsigned runflags)
+{
+ return runflags & COMEDI_SRF_ERROR;
+}
+
/**
* comedi_is_subdevice_running - check if async command running on subdevice
* @s: comedi_subdevice struct
@@ -634,17 +644,10 @@ bool comedi_is_subdevice_running(struct comedi_subdevice
*s)
{
unsigned runflags = comedi_get_subdevice_runflags(s);
- return (runflags & COMEDI_SRF_RUNNING) ? true : false;
+ return comedi_is_runflags_running(runflags);
}
EXPORT_SYMBOL_GPL(comedi_is_subdevice_running);
-static bool comedi_is_subdevice_in_error(struct comedi_subdevice *s)
-{
- unsigned runflags = comedi_get_subdevice_runflags(s);
-
- return (runflags & COMEDI_SRF_ERROR) ? true : false;
-}
-
static bool comedi_is_subdevice_idle(struct comedi_subdevice *s)
{
unsigned runflags = comedi_get_subdevice_runflags(s);
@@ -2282,13 +2285,16 @@ static ssize_t comedi_write(struct file *file, const
char __user *buf,
add_wait_queue(&async->wait_head, &wait);
on_wait_queue = true;
while (nbytes > 0 && !retval) {
+ unsigned runflags;
+
set_current_state(TASK_INTERRUPTIBLE);
- if (!comedi_is_subdevice_running(s)) {
+ runflags = comedi_get_subdevice_runflags(s);
+ if (!comedi_is_runflags_running(runflags)) {
if (count == 0) {
struct comedi_subdevice *new_s;
- if (comedi_is_subdevice_in_error(s))
+ if (comedi_is_runflags_in_error(runflags))
retval = -EPIPE;
else
retval = 0;
@@ -2435,8 +2441,10 @@ static ssize_t comedi_read(struct file *file, char
__user *buf, size_t nbytes,
n = m;
if (n == 0) {
- if (!comedi_is_subdevice_running(s)) {
- if (comedi_is_subdevice_in_error(s))
+ unsigned runflags = comedi_get_subdevice_runflags(s);
+
+ if (!comedi_is_runflags_running(runflags)) {
+ if (comedi_is_runflags_in_error(runflags))
retval = -EPIPE;
else
retval = 0;
--
2.1.4
--
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