[PATCH v3 4/5] thermal/drivers/db8500: convert to use devm_request_threaded_irq_emsg()

Yangtao Li
2023-07-03T09:05:40Z

There are more than 700 calls to the devm_request_threaded_irq method.
Most drivers only request one interrupt resource, and these error
messages are basically the same. If error messages are printed
everywhere, more than 1000 lines of code can be saved by removing the
msg in the driver.

And tglx point out that:

If we actually look at the call sites of
devm_request_threaded_irq() then the vast majority of them print more or
less lousy error messages. A quick grep/sed/awk/sort/uniq revealed

519 messages total (there are probably more)

352 unique messages

323 unique messages after lower casing

Those 323 are mostly just variants of the same patterns with
slight modifications in formatting and information provided.

186 of these messages do not deliver any useful information,
e.g. "no irq", "

The most useful one of all is: "could request wakeup irq: %d"

So there is certainly an argument to be made that this particular
function should print a well formatted and informative error message.

It's not a general allocator like kmalloc(). It's specialized and in the
vast majority of cases failing to request the interrupt causes the
device probe to fail. So having proper and consistent information why
the device cannot be used _is_ useful.

Let's use devm_request_threaded_irq_emsg(), which ensure that all error
handling branches print error information. In this way, when this function
fails, the upper-layer functions can directly return an error code without
missing debugging information. Otherwise, the error message will be
printed redundantly or missing.

Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Yangtao Li <frank.li@vivo.com>
---
drivers/thermal/db8500_thermal.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/drivers/thermal/db8500_thermal.c b/drivers/thermal/db8500_thermal.c
index fca5c2c93bf9..195caf954aca 100644
--- a/drivers/thermal/db8500_thermal.c
+++ b/drivers/thermal/db8500_thermal.c
@@ -164,25 +164,21 @@ static int db8500_thermal_probe(struct platform_device *pdev)
if (low_irq < 0)
return low_irq;

- ret = devm_request_threaded_irq(dev, low_irq, NULL,
+ ret = devm_request_threaded_irq_emsg(dev, low_irq, NULL,
prcmu_low_irq_handler, IRQF_NO_SUSPEND | IRQF_ONESHOT,
- "dbx500_temp_low", th);
- if (ret < 0) {
- dev_err(dev, "failed to allocate temp low irq\n");
+ "dbx500_temp_low", th, "temp low");
+ if (ret < 0)
return ret;
- }

high_irq = platform_get_irq_byname(pdev, "IRQ_HOTMON_HIGH");
if (high_irq < 0)
return high_irq;

- ret = devm_request_threaded_irq(dev, high_irq, NULL,
+ ret = devm_request_threaded_irq_emsg(dev, high_irq, NULL,
prcmu_high_irq_handler, IRQF_NO_SUSPEND | IRQF_ONESHOT,
- "dbx500_temp_high", th);
- if (ret < 0) {
- dev_err(dev, "failed to allocate temp high irq\n");
+ "dbx500_temp_high", th, "temp high");
+ if (ret < 0)
return ret;
- }

/* register of thermal sensor and get info from DT */
th->tz = devm_thermal_of_zone_register(dev, 0, th, &thdev_ops);
--
2.39.0