Hi Miaoqian,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on mtd/nand/next]
[also build test WARNING on linus/master linux/master v5.18-rc2 next-20220411]
[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/Miaoqian-Lin/mtd-rawnand-Fix-return-value-check-of-wait_for_completion_timeout/20220412-101006
base: https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git nand/next
config: hexagon-randconfig-r045-20220411 (https://download.01.org/0day-ci/archive/20220412/[email protected]/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project fe2478d44e4f7f191c43fef629ac7a23d0251e72)
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/3de25b46a3f73a3e0031e5186eb4e2afa9098b46
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Miaoqian-Lin/mtd-rawnand-Fix-return-value-check-of-wait_for_completion_timeout/20220412-101006
git checkout 3de25b46a3f73a3e0031e5186eb4e2afa9098b46
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash drivers/mtd/nand/raw/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
>> drivers/mtd/nand/raw/sh_flctl.c:433:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
if (time_left == 0) {
^~~~~~~~~~~~~~
drivers/mtd/nand/raw/sh_flctl.c:447:9: note: uninitialized use occurs here
return ret;
^~~
drivers/mtd/nand/raw/sh_flctl.c:433:2: note: remove the 'if' if its condition is always true
if (time_left == 0) {
^~~~~~~~~~~~~~~~~~~~
drivers/mtd/nand/raw/sh_flctl.c:387:9: note: initialize the variable 'ret' to silence this warning
int ret;
^
= 0
1 warning generated.
vim +433 drivers/mtd/nand/raw/sh_flctl.c
377
378 static int flctl_dma_fifo0_transfer(struct sh_flctl *flctl, unsigned long *buf,
379 int len, enum dma_data_direction dir)
380 {
381 struct dma_async_tx_descriptor *desc = NULL;
382 struct dma_chan *chan;
383 enum dma_transfer_direction tr_dir;
384 dma_addr_t dma_addr;
385 dma_cookie_t cookie;
386 uint32_t reg;
387 int ret;
388 unsigned long time_left;
389
390 if (dir == DMA_FROM_DEVICE) {
391 chan = flctl->chan_fifo0_rx;
392 tr_dir = DMA_DEV_TO_MEM;
393 } else {
394 chan = flctl->chan_fifo0_tx;
395 tr_dir = DMA_MEM_TO_DEV;
396 }
397
398 dma_addr = dma_map_single(chan->device->dev, buf, len, dir);
399
400 if (!dma_mapping_error(chan->device->dev, dma_addr))
401 desc = dmaengine_prep_slave_single(chan, dma_addr, len,
402 tr_dir, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
403
404 if (desc) {
405 reg = readl(FLINTDMACR(flctl));
406 reg |= DREQ0EN;
407 writel(reg, FLINTDMACR(flctl));
408
409 desc->callback = flctl_dma_complete;
410 desc->callback_param = flctl;
411 cookie = dmaengine_submit(desc);
412 if (dma_submit_error(cookie)) {
413 ret = dma_submit_error(cookie);
414 dev_warn(&flctl->pdev->dev,
415 "DMA submit failed, falling back to PIO\n");
416 goto out;
417 }
418
419 dma_async_issue_pending(chan);
420 } else {
421 /* DMA failed, fall back to PIO */
422 flctl_release_dma(flctl);
423 dev_warn(&flctl->pdev->dev,
424 "DMA failed, falling back to PIO\n");
425 ret = -EIO;
426 goto out;
427 }
428
429 time_left =
430 wait_for_completion_timeout(&flctl->dma_complete,
431 msecs_to_jiffies(3000));
432
> 433 if (time_left == 0) {
434 dmaengine_terminate_all(chan);
435 dev_err(&flctl->pdev->dev, "wait_for_completion_timeout\n");
436 ret = -ETIMEDOUT;
437 }
438
439 out:
440 reg = readl(FLINTDMACR(flctl));
441 reg &= ~DREQ0EN;
442 writel(reg, FLINTDMACR(flctl));
443
444 dma_unmap_single(chan->device->dev, dma_addr, len, dir);
445
446 /* ret > 0 is success */
447 return ret;
448 }
449
--
0-DAY CI Kernel Test Service
https://01.org/lkp
wait_for_completion_timeout() returns unsigned long not int.
It returns 0 if timed out, and positive if completed.
The check for <= 0 is ambiguous and should be == 0 here
indicating timeout which is the only error case.
Fixes: 83738d87e3a0 ("mtd: sh_flctl: Add DMA capabilty")
Signed-off-by: Miaoqian Lin <[email protected]>
---
change in v2:
- initialize ret to 1.
---
drivers/mtd/nand/raw/sh_flctl.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/drivers/mtd/nand/raw/sh_flctl.c b/drivers/mtd/nand/raw/sh_flctl.c
index b85b9c6fcc42..2373251f585b 100644
--- a/drivers/mtd/nand/raw/sh_flctl.c
+++ b/drivers/mtd/nand/raw/sh_flctl.c
@@ -384,7 +384,8 @@ static int flctl_dma_fifo0_transfer(struct sh_flctl *flctl, unsigned long *buf,
dma_addr_t dma_addr;
dma_cookie_t cookie;
uint32_t reg;
- int ret;
+ int ret = 1;
+ unsigned long time_left;
if (dir == DMA_FROM_DEVICE) {
chan = flctl->chan_fifo0_rx;
@@ -425,13 +426,14 @@ static int flctl_dma_fifo0_transfer(struct sh_flctl *flctl, unsigned long *buf,
goto out;
}
- ret =
+ time_left =
wait_for_completion_timeout(&flctl->dma_complete,
msecs_to_jiffies(3000));
- if (ret <= 0) {
+ if (time_left == 0) {
dmaengine_terminate_all(chan);
dev_err(&flctl->pdev->dev, "wait_for_completion_timeout\n");
+ ret = -ETIMEDOUT;
}
out:
--
2.17.1
Hi Miaoqian,
[email protected] wrote on Tue, 12 Apr 2022 06:36:52 +0000:
> wait_for_completion_timeout() returns unsigned long not int.
> It returns 0 if timed out, and positive if completed.
> The check for <= 0 is ambiguous and should be == 0 here
> indicating timeout which is the only error case.
>
> Fixes: 83738d87e3a0 ("mtd: sh_flctl: Add DMA capabilty")
> Signed-off-by: Miaoqian Lin <[email protected]>
> ---
> change in v2:
> - initialize ret to 1.
> ---
> drivers/mtd/nand/raw/sh_flctl.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mtd/nand/raw/sh_flctl.c b/drivers/mtd/nand/raw/sh_flctl.c
> index b85b9c6fcc42..2373251f585b 100644
> --- a/drivers/mtd/nand/raw/sh_flctl.c
> +++ b/drivers/mtd/nand/raw/sh_flctl.c
> @@ -384,7 +384,8 @@ static int flctl_dma_fifo0_transfer(struct sh_flctl *flctl, unsigned long *buf,
> dma_addr_t dma_addr;
> dma_cookie_t cookie;
> uint32_t reg;
> - int ret;
> + int ret = 1;
Does not look right. I know this function returns > 0 on positive
outcomes but this does not make any sense in the first place.
This function is static and only called twice, please turn it into
something like:
if (dma_fifo_transfer())
error
else
ok
> + unsigned long time_left;
>
> if (dir == DMA_FROM_DEVICE) {
> chan = flctl->chan_fifo0_rx;
> @@ -425,13 +426,14 @@ static int flctl_dma_fifo0_transfer(struct sh_flctl *flctl, unsigned long *buf,
> goto out;
> }
>
> - ret =
> + time_left =
> wait_for_completion_timeout(&flctl->dma_complete,
> msecs_to_jiffies(3000));
>
> - if (ret <= 0) {
> + if (time_left == 0) {
> dmaengine_terminate_all(chan);
> dev_err(&flctl->pdev->dev, "wait_for_completion_timeout\n");
> + ret = -ETIMEDOUT;
> }
>
> out:
Thanks,
Miquèl
Hi Miquel,
On 2022/4/12 15:48, Miquel Raynal wrote:
>
>>> Hi Miaoqian,
>>>
>>> [email protected] wrote on Tue, 12 Apr 2022 06:36:52 +0000:
>>>
>>>> wait_for_completion_timeout() returns unsigned long not int.
>>>> It returns 0 if timed out, and positive if completed.
>>>> The check for <= 0 is ambiguous and should be == 0 here
>>>> indicating timeout which is the only error case.
>>>>
>>>> Fixes: 83738d87e3a0 ("mtd: sh_flctl: Add DMA capabilty")
>>>> Signed-off-by: Miaoqian Lin <[email protected]>
>>>> ---
>>>> change in v2:
>>>> - initialize ret to 1.
>>>> ---
>>>> drivers/mtd/nand/raw/sh_flctl.c | 8 +++++---
>>>> 1 file changed, 5 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/mtd/nand/raw/sh_flctl.c b/drivers/mtd/nand/raw/sh_flctl.c
>>>> index b85b9c6fcc42..2373251f585b 100644
>>>> --- a/drivers/mtd/nand/raw/sh_flctl.c
>>>> +++ b/drivers/mtd/nand/raw/sh_flctl.c
>>>> @@ -384,7 +384,8 @@ static int flctl_dma_fifo0_transfer(struct sh_flctl *flctl, unsigned long *buf,
>>>> dma_addr_t dma_addr;
>>>> dma_cookie_t cookie;
>>>> uint32_t reg;
>>>> - int ret;
>>>> + int ret = 1;
>>> Does not look right. I know this function returns > 0 on positive
>>> outcomes but this does not make any sense in the first place.
>> Yes, I made a mistake, Now I realize that in v2, it will return 1 in error path
>>
>> when DMA submit failed.
> Not 1, but a proper error code please (-ETIMEDOUT, -EINVAL, whatever)
>
>> And for patch v1, it will return 0 if calls wait_for_completion_timeout succeeds.
>>
>>> This function is static and only called twice, please turn it into
>>> something like:
>>>
>>> if (dma_fifo_transfer())
>>> error
>>> else
>>> ok
>> So I want to keep ret>0 means success.
>>
>> Or could I set ret > 0 after in wait_for_completion_timeout() success path?
>>
>> like:
>>
>> if(time_left == 0)
>>
>> ret = -ETIMEDOUT;
>>
>> else
>>
>> ret = 1;
> You can initialize ret to zero at to top. So that anything != 0 is an
> error (like a lot of functions in the kernel).
Thanks for your advice, I will do this.
> And use:
>
> if (dma_fifo_transfer())
> error();
I think keeping the original condition structure is better,
something like:
if (dma_fifo_transfer()==0)
succeed();
In this way, only minor changes is needed——only need to update the symbol in condition.
Otherwise It needs to restructure the code and be more complicated.
Thanks,
>> What do you think?
>>
>>
>> Thanks,
>>
>>>> + unsigned long time_left;
>>>>
>>>> if (dir == DMA_FROM_DEVICE) {
>>>> chan = flctl->chan_fifo0_rx;
>>>> @@ -425,13 +426,14 @@ static int flctl_dma_fifo0_transfer(struct sh_flctl *flctl, unsigned long *buf,
>>>> goto out;
>>>> }
>>>>
>>>> - ret =
>>>> + time_left =
>>>> wait_for_completion_timeout(&flctl->dma_complete,
>>>> msecs_to_jiffies(3000));
>>>>
>>>> - if (ret <= 0) {
>>>> + if (time_left == 0) {
>>>> dmaengine_terminate_all(chan);
>>>> dev_err(&flctl->pdev->dev, "wait_for_completion_timeout\n");
>>>> + ret = -ETIMEDOUT;
>>>> }
>>>>
>>>> out:
>>> Thanks,
>>> Miquèl
>
> Thanks,
> Miquèl
Hi Miquel,
Thanks for your reply.
On 2022/4/12 15:06, Miquel Raynal wrote:
> Hi Miaoqian,
>
> [email protected] wrote on Tue, 12 Apr 2022 06:36:52 +0000:
>
>> wait_for_completion_timeout() returns unsigned long not int.
>> It returns 0 if timed out, and positive if completed.
>> The check for <= 0 is ambiguous and should be == 0 here
>> indicating timeout which is the only error case.
>>
>> Fixes: 83738d87e3a0 ("mtd: sh_flctl: Add DMA capabilty")
>> Signed-off-by: Miaoqian Lin <[email protected]>
>> ---
>> change in v2:
>> - initialize ret to 1.
>> ---
>> drivers/mtd/nand/raw/sh_flctl.c | 8 +++++---
>> 1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/mtd/nand/raw/sh_flctl.c b/drivers/mtd/nand/raw/sh_flctl.c
>> index b85b9c6fcc42..2373251f585b 100644
>> --- a/drivers/mtd/nand/raw/sh_flctl.c
>> +++ b/drivers/mtd/nand/raw/sh_flctl.c
>> @@ -384,7 +384,8 @@ static int flctl_dma_fifo0_transfer(struct sh_flctl *flctl, unsigned long *buf,
>> dma_addr_t dma_addr;
>> dma_cookie_t cookie;
>> uint32_t reg;
>> - int ret;
>> + int ret = 1;
> Does not look right. I know this function returns > 0 on positive
> outcomes but this does not make any sense in the first place.
Yes, I made a mistake, Now I realize that in v2, it will return 1 in error path
when DMA submit failed.
And for patch v1, it will return 0 if calls wait_for_completion_timeout succeeds.
> This function is static and only called twice, please turn it into
> something like:
>
> if (dma_fifo_transfer())
> error
> else
> ok
So I want to keep ret>0 means success.
Or could I set ret > 0 after in wait_for_completion_timeout() success path?
like:
if(time_left == 0)
ret = -ETIMEDOUT;
else
ret = 1;
What do you think?
Thanks,
>> + unsigned long time_left;
>>
>> if (dir == DMA_FROM_DEVICE) {
>> chan = flctl->chan_fifo0_rx;
>> @@ -425,13 +426,14 @@ static int flctl_dma_fifo0_transfer(struct sh_flctl *flctl, unsigned long *buf,
>> goto out;
>> }
>>
>> - ret =
>> + time_left =
>> wait_for_completion_timeout(&flctl->dma_complete,
>> msecs_to_jiffies(3000));
>>
>> - if (ret <= 0) {
>> + if (time_left == 0) {
>> dmaengine_terminate_all(chan);
>> dev_err(&flctl->pdev->dev, "wait_for_completion_timeout\n");
>> + ret = -ETIMEDOUT;
>> }
>>
>> out:
>
> Thanks,
> Miquèl
Hi Miaoqian,
[email protected] wrote on Tue, 12 Apr 2022 15:42:02 +0800:
> Hi Miquel,
>
> Thanks for your reply.
>
> On 2022/4/12 15:06, Miquel Raynal wrote:
> > Hi Miaoqian,
> >
> > [email protected] wrote on Tue, 12 Apr 2022 06:36:52 +0000:
> >
> >> wait_for_completion_timeout() returns unsigned long not int.
> >> It returns 0 if timed out, and positive if completed.
> >> The check for <= 0 is ambiguous and should be == 0 here
> >> indicating timeout which is the only error case.
> >>
> >> Fixes: 83738d87e3a0 ("mtd: sh_flctl: Add DMA capabilty")
> >> Signed-off-by: Miaoqian Lin <[email protected]>
> >> ---
> >> change in v2:
> >> - initialize ret to 1.
> >> ---
> >> drivers/mtd/nand/raw/sh_flctl.c | 8 +++++---
> >> 1 file changed, 5 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/drivers/mtd/nand/raw/sh_flctl.c b/drivers/mtd/nand/raw/sh_flctl.c
> >> index b85b9c6fcc42..2373251f585b 100644
> >> --- a/drivers/mtd/nand/raw/sh_flctl.c
> >> +++ b/drivers/mtd/nand/raw/sh_flctl.c
> >> @@ -384,7 +384,8 @@ static int flctl_dma_fifo0_transfer(struct sh_flctl *flctl, unsigned long *buf,
> >> dma_addr_t dma_addr;
> >> dma_cookie_t cookie;
> >> uint32_t reg;
> >> - int ret;
> >> + int ret = 1;
> > Does not look right. I know this function returns > 0 on positive
> > outcomes but this does not make any sense in the first place.
>
> Yes, I made a mistake, Now I realize that in v2, it will return 1 in error path
>
> when DMA submit failed.
Not 1, but a proper error code please (-ETIMEDOUT, -EINVAL, whatever)
>
> And for patch v1, it will return 0 if calls wait_for_completion_timeout succeeds.
>
> > This function is static and only called twice, please turn it into
> > something like:
> >
> > if (dma_fifo_transfer())
> > error
> > else
> > ok
>
> So I want to keep ret>0 means success.
>
> Or could I set ret > 0 after in wait_for_completion_timeout() success path?
>
> like:
>
> if(time_left == 0)
>
> ret = -ETIMEDOUT;
>
> else
>
> ret = 1;
You can initialize ret to zero at to top. So that anything != 0 is an
error (like a lot of functions in the kernel). And use:
if (dma_fifo_transfer())
error();
>
> What do you think?
>
>
> Thanks,
>
> >> + unsigned long time_left;
> >>
> >> if (dir == DMA_FROM_DEVICE) {
> >> chan = flctl->chan_fifo0_rx;
> >> @@ -425,13 +426,14 @@ static int flctl_dma_fifo0_transfer(struct sh_flctl *flctl, unsigned long *buf,
> >> goto out;
> >> }
> >>
> >> - ret =
> >> + time_left =
> >> wait_for_completion_timeout(&flctl->dma_complete,
> >> msecs_to_jiffies(3000));
> >>
> >> - if (ret <= 0) {
> >> + if (time_left == 0) {
> >> dmaengine_terminate_all(chan);
> >> dev_err(&flctl->pdev->dev, "wait_for_completion_timeout\n");
> >> + ret = -ETIMEDOUT;
> >> }
> >>
> >> out:
> >
> > Thanks,
> > Miquèl
Thanks,
Miquèl