From b183a836fe02a59c2b55273655196ba288f3adb7 Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Fri, 27 Mar 2015 15:13:01 +0000 Subject: [PATCH] staging: comedi: comedi_fops: eliminate a use of subdevice spin-lock `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 Reviewed-by: H Hartley Sweeten Signed-off-by: Greg Kroah-Hartman --- 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 2b75b7a1cee0..17ac2858205d 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; -- 2.20.1