[PATCH 2/2] firmware_class: Move request_firmware_nowait() to workqueues

From: Stephen Boyd
Date: Tue Mar 27 2012 - 17:28:36 EST


Oddly enough a work_struct was already part of the firmware_work
structure but nobody was using it. Instead of creating a new
kthread for each request_firmware_nowait() call just schedule the
work on the long system workqueue. This should avoid some overhead
in forking new threads when they're not strictly necessary.

Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
---

Is it better to use alloc_workqueue() and not put these on the system
long workqueue?

drivers/base/firmware_class.c | 27 +++++++--------------------
1 file changed, 7 insertions(+), 20 deletions(-)

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index ae00a2f..4d8cb8b 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -16,10 +16,11 @@
#include <linux/interrupt.h>
#include <linux/bitops.h>
#include <linux/mutex.h>
-#include <linux/kthread.h>
+#include <linux/workqueue.h>
#include <linux/highmem.h>
#include <linux/firmware.h>
#include <linux/slab.h>
+#include <linux/sched.h>

#define to_dev(obj) container_of(obj, struct device, kobj)

@@ -630,19 +631,15 @@ struct firmware_work {
bool uevent;
};

-static int request_firmware_work_func(void *arg)
+static void request_firmware_work_func(struct work_struct *work)
{
- struct firmware_work *fw_work = arg;
+ struct firmware_work *fw_work;
const struct firmware *fw;
struct firmware_priv *fw_priv;
long timeout;
int ret;

- if (!arg) {
- WARN_ON(1);
- return 0;
- }
-
+ fw_work = container_of(work, struct firmware_work, work);
fw_priv = _request_firmware_prepare(&fw, fw_work->name, fw_work->device,
fw_work->uevent, true);
if (IS_ERR_OR_NULL(fw_priv)) {
@@ -667,8 +664,6 @@ static int request_firmware_work_func(void *arg)

module_put(fw_work->module);
kfree(fw_work);
-
- return ret;
}

/**
@@ -694,7 +689,6 @@ request_firmware_nowait(
const char *name, struct device *device, gfp_t gfp, void *context,
void (*cont)(const struct firmware *fw, void *context))
{
- struct task_struct *task;
struct firmware_work *fw_work;

fw_work = kzalloc(sizeof (struct firmware_work), gfp);
@@ -713,15 +707,8 @@ request_firmware_nowait(
return -EFAULT;
}

- task = kthread_run(request_firmware_work_func, fw_work,
- "firmware/%s", name);
- if (IS_ERR(task)) {
- fw_work->cont(NULL, fw_work->context);
- module_put(fw_work->module);
- kfree(fw_work);
- return PTR_ERR(task);
- }
-
+ INIT_WORK(&fw_work->work, request_firmware_work_func);
+ queue_work(system_long_wq, &fw_work->work);
return 0;
}

--
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.

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