drivers/memory/tegra/tegra20-emc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
of_find_node_by_name() will decrease the refcount of its first arg and
we need to add a of_node_put() to keep refcount balance.
Besides, during the 'for' loop execution, the refcount of 'np' will be
automatically increased and decreased. There is no need to call
of_node_put() again.
Signed-off-by: Liang He <windhl@126.com>
---
drivers/memory/tegra/tegra20-emc.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/memory/tegra/tegra20-emc.c b/drivers/memory/tegra/tegra20-emc.c
index 25ba3c5e4ad6..e43a5f8e188e 100644
--- a/drivers/memory/tegra/tegra20-emc.c
+++ b/drivers/memory/tegra/tegra20-emc.c
@@ -477,6 +477,7 @@ tegra_emc_find_node_by_ram_code(struct tegra_emc *emc)
ram_code = tegra_read_ram_code();
+ of_get_node(dev->of_node);
for (np = of_find_node_by_name(dev->of_node, "emc-tables"); np;
np = of_find_node_by_name(np, "emc-tables")) {
err = of_property_read_u32(np, "nvidia,ram-code", &value);
@@ -484,6 +485,7 @@ tegra_emc_find_node_by_ram_code(struct tegra_emc *emc)
struct device_node *lpddr2_np;
bool cfg_mismatches = false;
+ of_node_get(np);
lpddr2_np = of_find_node_by_name(np, "lpddr2");
if (lpddr2_np) {
const struct lpddr2_info *info;
@@ -521,7 +523,6 @@ tegra_emc_find_node_by_ram_code(struct tegra_emc *emc)
}
if (cfg_mismatches) {
- of_node_put(np);
continue;
}
}
--
2.25.1On 22/06/2022 06:28, Liang He wrote: > of_find_node_by_name() will decrease the refcount of its first arg and > we need to add a of_node_put() to keep refcount balance. > > Besides, during the 'for' loop execution, the refcount of 'np' will be > automatically increased and decreased. There is no need to call > of_node_put() again. > > Signed-off-by: Liang He <windhl@126.com> > --- > drivers/memory/tegra/tegra20-emc.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > The patch was not even compiled... I consider it harmful approach. NAK. See: https://lwn.net/Articles/854645/ Best regards, Krzysztof
At 2022-06-22 16:41:28, "Krzysztof Kozlowski" <krzysztof.kozlowski@linaro.org> wrote: >On 22/06/2022 06:28, Liang He wrote: >> of_find_node_by_name() will decrease the refcount of its first arg and >> we need to add a of_node_put() to keep refcount balance. >> >> Besides, during the 'for' loop execution, the refcount of 'np' will be >> automatically increased and decreased. There is no need to call >> of_node_put() again. >> >> Signed-off-by: Liang He <windhl@126.com> >> --- >> drivers/memory/tegra/tegra20-emc.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> > >The patch was not even compiled... I consider it harmful approach. NAK. >See: https://lwn.net/Articles/854645/ > >Best regards, >Krzysztof Sorry, Krzysztof. As the patch is so simple two lines , I thought I can handle it without compiling it. Thanks very much for your notice about the article and I hope I have not done anyother harmful things. And I will take care of my patch code in future no matter how simple it is.
On 22/06/2022 10:49, Liang He wrote: > > > At 2022-06-22 16:41:28, "Krzysztof Kozlowski" <krzysztof.kozlowski@linaro.org> wrote: >> On 22/06/2022 06:28, Liang He wrote: >>> of_find_node_by_name() will decrease the refcount of its first arg and >>> we need to add a of_node_put() to keep refcount balance. >>> >>> Besides, during the 'for' loop execution, the refcount of 'np' will be >>> automatically increased and decreased. There is no need to call >>> of_node_put() again. >>> >>> Signed-off-by: Liang He <windhl@126.com> >>> --- >>> drivers/memory/tegra/tegra20-emc.c | 3 ++- >>> 1 file changed, 2 insertions(+), 1 deletion(-) >>> >> >> The patch was not even compiled... I consider it harmful approach. NAK. >> See: https://lwn.net/Articles/854645/ >> >> Best regards, >> Krzysztof > > Sorry, Krzysztof. > > As the patch is so simple two lines , I thought I can handle it without compiling it. > > Thanks very much for your notice about the article and I hope I have not done anyother harmful things. > > And I will take care of my patch code in future no matter how simple it is. Never send patches which were not built. It seems you didn't build them in the past either, even though setting up cross compile is trivial (few commands). QEMU is also an easy option. Even though your contribution might be valuable, lack of building is a sign for me that approach is not serious, so I am not going to take risky code. Best regards, Krzysztof
At 2022-06-22 17:08:32, "Krzysztof Kozlowski" <krzysztof.kozlowski@linaro.org> wrote: >On 22/06/2022 10:49, Liang He wrote: >> >> >> At 2022-06-22 16:41:28, "Krzysztof Kozlowski" <krzysztof.kozlowski@linaro.org> wrote: >>> On 22/06/2022 06:28, Liang He wrote: >>>> of_find_node_by_name() will decrease the refcount of its first arg and >>>> we need to add a of_node_put() to keep refcount balance. >>>> >>>> Besides, during the 'for' loop execution, the refcount of 'np' will be >>>> automatically increased and decreased. There is no need to call >>>> of_node_put() again. >>>> >>>> Signed-off-by: Liang He <windhl@126.com> >>>> --- >>>> drivers/memory/tegra/tegra20-emc.c | 3 ++- >>>> 1 file changed, 2 insertions(+), 1 deletion(-) >>>> >>> >>> The patch was not even compiled... I consider it harmful approach. NAK. >>> See: https://lwn.net/Articles/854645/ >>> >>> Best regards, >>> Krzysztof >> >> Sorry, Krzysztof. >> >> As the patch is so simple two lines , I thought I can handle it without compiling it. >> >> Thanks very much for your notice about the article and I hope I have not done anyother harmful things. >> >> And I will take care of my patch code in future no matter how simple it is. > > >Never send patches which were not built. It seems you didn't build them >in the past either, even though setting up cross compile is trivial (few >commands). QEMU is also an easy option. > >Even though your contribution might be valuable, lack of building is a >sign for me that approach is not serious, so I am not going to take >risky code. > >Best regards, >Krzysztof Thanks, Krzysztof. This a valuable lesson for me. Last few days, I just want to report the bugs as quickly as I can. And I only focus the bugs I found but not the patch compiling problem. Yes, I admit this approach (way) is not serious and this is my fault, sorry again and sorry to waste your time. From now on, I will not send any new patch commit before I compile the patch code. Sorry for my behavior.
On 22/06/2022 11:08, Krzysztof Kozlowski wrote: >>> The patch was not even compiled... I consider it harmful approach. NAK. >>> See: https://lwn.net/Articles/854645/ >>> >>> Best regards, >>> Krzysztof >> >> Sorry, Krzysztof. >> >> As the patch is so simple two lines , I thought I can handle it without compiling it. >> >> Thanks very much for your notice about the article and I hope I have not done anyother harmful things. >> >> And I will take care of my patch code in future no matter how simple it is. > > > Never send patches which were not built. It seems you didn't build them > in the past either, even though setting up cross compile is trivial (few > commands). QEMU is also an easy option. > > Even though your contribution might be valuable, lack of building is a > sign for me that approach is not serious, so I am not going to take > risky code. Unless of course someone's reviews your code. :) Best regards, Krzysztof
Hi Liang,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on tegra/for-next]
[also build test ERROR on tegra-drm/drm/tegra/for-next linus/master v5.19-rc3 next-20220621]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/intel-lab-lkp/linux/commits/Liang-He/memory-tegra-Add-missing-of_node_get-in-tegra_emc_find_node_by_ram_code/20220622-123052
base: https://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux.git for-next
config: hexagon-randconfig-r041-20220622 (https://download.01.org/0day-ci/archive/20220622/202206221602.odN70SHs-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 8b8d126598ce7bd5243da7f94f69fa1104288bee)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/6f5dd7a2fb5c7d45a25cdf4409c5aa03c4df0a96
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Liang-He/memory-tegra-Add-missing-of_node_get-in-tegra_emc_find_node_by_ram_code/20220622-123052
git checkout 6f5dd7a2fb5c7d45a25cdf4409c5aa03c4df0a96
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash drivers/memory/tegra/
If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
>> drivers/memory/tegra/tegra20-emc.c:480:2: error: call to undeclared function 'of_get_node'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
of_get_node(dev->of_node);
^
1 error generated.
vim +/of_get_node +480 drivers/memory/tegra/tegra20-emc.c
456
457 static struct device_node *
458 tegra_emc_find_node_by_ram_code(struct tegra_emc *emc)
459 {
460 struct device *dev = emc->dev;
461 struct device_node *np;
462 u32 value, ram_code;
463 int err;
464
465 if (emc->mrr_error) {
466 dev_warn(dev, "memory timings skipped due to MRR error\n");
467 return NULL;
468 }
469
470 if (of_get_child_count(dev->of_node) == 0) {
471 dev_info_once(dev, "device-tree doesn't have memory timings\n");
472 return NULL;
473 }
474
475 if (!of_property_read_bool(dev->of_node, "nvidia,use-ram-code"))
476 return of_node_get(dev->of_node);
477
478 ram_code = tegra_read_ram_code();
479
> 480 of_get_node(dev->of_node);
481 for (np = of_find_node_by_name(dev->of_node, "emc-tables"); np;
482 np = of_find_node_by_name(np, "emc-tables")) {
483 err = of_property_read_u32(np, "nvidia,ram-code", &value);
484 if (err || value != ram_code) {
485 struct device_node *lpddr2_np;
486 bool cfg_mismatches = false;
487
488 of_node_get(np);
489 lpddr2_np = of_find_node_by_name(np, "lpddr2");
490 if (lpddr2_np) {
491 const struct lpddr2_info *info;
492
493 info = of_lpddr2_get_info(lpddr2_np, dev);
494 if (info) {
495 if (info->manufacturer_id >= 0 &&
496 info->manufacturer_id != emc->manufacturer_id)
497 cfg_mismatches = true;
498
499 if (info->revision_id1 >= 0 &&
500 info->revision_id1 != emc->revision_id1)
501 cfg_mismatches = true;
502
503 if (info->revision_id2 >= 0 &&
504 info->revision_id2 != emc->revision_id2)
505 cfg_mismatches = true;
506
507 if (info->density != emc->basic_conf4.density)
508 cfg_mismatches = true;
509
510 if (info->io_width != emc->basic_conf4.io_width)
511 cfg_mismatches = true;
512
513 if (info->arch_type != emc->basic_conf4.arch_type)
514 cfg_mismatches = true;
515 } else {
516 dev_err(dev, "failed to parse %pOF\n", lpddr2_np);
517 cfg_mismatches = true;
518 }
519
520 of_node_put(lpddr2_np);
521 } else {
522 cfg_mismatches = true;
523 }
524
525 if (cfg_mismatches) {
526 continue;
527 }
528 }
529
530 return np;
531 }
532
533 dev_err(dev, "no memory timings for RAM code %u found in device tree\n",
534 ram_code);
535
536 return NULL;
537 }
538
--
0-DAY CI Kernel Test Service
https://01.org/lkp
On 22/06/2022 06:28, Liang He wrote:
> of_find_node_by_name() will decrease the refcount of its first arg and
> we need to add a of_node_put() to keep refcount balance.
We do NOT need to add an of_node_put?
Anyway why do you add of_node_get which is not explained here?
>
> Besides, during the 'for' loop execution, the refcount of 'np' will be
> automatically increased and decreased. There is no need to call
> of_node_put() again.
>
> Signed-off-by: Liang He <windhl@126.com>
> ---
> drivers/memory/tegra/tegra20-emc.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/memory/tegra/tegra20-emc.c b/drivers/memory/tegra/tegra20-emc.c
> index 25ba3c5e4ad6..e43a5f8e188e 100644
> --- a/drivers/memory/tegra/tegra20-emc.c
> +++ b/drivers/memory/tegra/tegra20-emc.c
> @@ -477,6 +477,7 @@ tegra_emc_find_node_by_ram_code(struct tegra_emc *emc)
>
> ram_code = tegra_read_ram_code();
>
> + of_get_node(dev->of_node);
> for (np = of_find_node_by_name(dev->of_node, "emc-tables"); np;
> np = of_find_node_by_name(np, "emc-tables")) {
> err = of_property_read_u32(np, "nvidia,ram-code", &value);
> @@ -484,6 +485,7 @@ tegra_emc_find_node_by_ram_code(struct tegra_emc *emc)
> struct device_node *lpddr2_np;
> bool cfg_mismatches = false;
>
> + of_node_get(np);
> lpddr2_np = of_find_node_by_name(np, "lpddr2");
> if (lpddr2_np) {
> const struct lpddr2_info *info;
> @@ -521,7 +523,6 @@ tegra_emc_find_node_by_ram_code(struct tegra_emc *emc)
> }
>
> if (cfg_mismatches) {
> - of_node_put(np);
> continue;
> }
> }
Best regards,
Krzysztof
At 2022-06-22 14:50:41, "Krzysztof Kozlowski" <krzysztof.kozlowski@linaro.org> wrote:
>On 22/06/2022 06:28, Liang He wrote:
>> of_find_node_by_name() will decrease the refcount of its first arg and
>> we need to add a of_node_put() to keep refcount balance.
>
>We do NOT need to add an of_node_put?
>
Sorry, this is a typo, I want to say we need to add a 'of_node_get()'
>Anyway why do you add of_node_get which is not explained here?
>
This is a common mistake that missing the of_node_get(X) before we call
of_find_node_by_name(X,..) as the of_find_xxx will decrease the refcount of X.
A similar error is:
https://lore.kernel.org/all/20200720152806.443262648@linuxfoundation.org/
If I am wrong, please correct me, thanks.
>>
>> Besides, during the 'for' loop execution, the refcount of 'np' will be
>> automatically increased and decreased. There is no need to call
>> of_node_put() again.
>>
>> Signed-off-by: Liang He <windhl@126.com>
>> ---
>> drivers/memory/tegra/tegra20-emc.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/memory/tegra/tegra20-emc.c b/drivers/memory/tegra/tegra20-emc.c
>> index 25ba3c5e4ad6..e43a5f8e188e 100644
>> --- a/drivers/memory/tegra/tegra20-emc.c
>> +++ b/drivers/memory/tegra/tegra20-emc.c
>> @@ -477,6 +477,7 @@ tegra_emc_find_node_by_ram_code(struct tegra_emc *emc)
>>
>> ram_code = tegra_read_ram_code();
>>
>> + of_get_node(dev->of_node);
>> for (np = of_find_node_by_name(dev->of_node, "emc-tables"); np;
>> np = of_find_node_by_name(np, "emc-tables")) {
>> err = of_property_read_u32(np, "nvidia,ram-code", &value);
>> @@ -484,6 +485,7 @@ tegra_emc_find_node_by_ram_code(struct tegra_emc *emc)
>> struct device_node *lpddr2_np;
>> bool cfg_mismatches = false;
>>
>> + of_node_get(np);
>> lpddr2_np = of_find_node_by_name(np, "lpddr2");
>> if (lpddr2_np) {
>> const struct lpddr2_info *info;
>> @@ -521,7 +523,6 @@ tegra_emc_find_node_by_ram_code(struct tegra_emc *emc)
>> }
>>
>> if (cfg_mismatches) {
>> - of_node_put(np);
>> continue;
>> }
>> }
>
>
>Best regards,
>Krzysztof
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