Messages in this thread Patch in this message | | | Date | Mon, 26 Dec 2022 17:02:35 +0100 (CET) | From | Julia Lawall <> | Subject | Re: coccinelle: How to remove a return at the end of a void function? |
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On Sun, 25 Dec 2022, Uwe Kleine-König wrote:
> Hello Julia, > > first of all thanks for your quick answer. > > On Sat, Dec 24, 2022 at 01:28:04PM +0100, Julia Lawall wrote: > > On Sat, 24 Dec 2022, Uwe Kleine-König wrote: > > > A simplified spatch looks as follows: > > > > > > -------->8-------- > > > virtual patch > > > > > > @p1@ > > > identifier pdev; > > > @@ > > > -int > > > +void > > > rtsx_usb_sdmmc_drv_remove(struct platform_device *pdev) { > > > <... > > > -return 0; > > > +return; > > > ...> > > > } > > > -------->8-------- > > > > > > This results in: > > > > > > -------->8-------- > > > diff -u -p a/drivers/mmc/host/rtsx_usb_sdmmc.c b/drivers/mmc/host/rtsx_usb_sdmmc.c > > > --- a/drivers/mmc/host/rtsx_usb_sdmmc.c > > > +++ b/drivers/mmc/host/rtsx_usb_sdmmc.c > > > @@ -1379,13 +1379,13 @@ static int rtsx_usb_sdmmc_drv_probe(stru > > > return 0; > > > } > > > > > > -static int rtsx_usb_sdmmc_drv_remove(struct platform_device *pdev) > > > +static void rtsx_usb_sdmmc_drv_remove(struct platform_device *pdev) > > > { > > > struct rtsx_usb_sdmmc *host = platform_get_drvdata(pdev); > > > struct mmc_host *mmc; > > > > > > if (!host) > > > - return 0; > > > + return; > > > > > > mmc = host->mmc; > > > host->host_removal = true; > > > @@ -1416,7 +1416,7 @@ static int rtsx_usb_sdmmc_drv_remove(str > > > dev_dbg(&(pdev->dev), > > > ": Realtek USB SD/MMC module has been removed\n"); > > > > > > - return 0; > > > + return; > > > } > > > > > > #ifdef CONFIG_PM > > > -------->8-------- > > > > > > which is as intended. Now I want to remove the useless "return;" at the > > > end of the function, however adding > > > > > > -------->8-------- > > > @p2 depends on p1@ > > > identifier pdev; > > > @@ > > > void rtsx_usb_sdmmc_drv_remove(struct platform_device *pdev) { > > > ... > > > -return; > > > } > > > -------->8-------- > > > > > > to the spatch doesn't (only) do the intended: > > > > The problem is that Coccinelle is following the control-flow through the > > function, and all of the returns are at the end of a control.flow path. > > The simple, hacky solution is to change the return;s into some function > > call Return();, then do like the above for Return(); and then change the > > Return();s back to return;s > > OK, I tried, but somehow coccinelle refuse to work after I introduced > Return(), even replacing them by return; doesn't work: > > -------->8-------- > virtual patch > > @p1@ > identifier pdev; > @@ > -int > +void > rtsx_usb_sdmmc_drv_remove(struct platform_device *pdev) { > ... > -return 0; > +Return(); > ... > } > > @p2@ > identifier pdev; > @@ > void rtsx_usb_sdmmc_drv_remove(struct platform_device *pdev) { > ... > -Return(); > +return; > ... > }
The problem is that a control-flow path at this point can have multiple calls to Return(); You pattern only matches when every control-flow path through the code has exactly one Return().
You should have one rule that removes the final Return();
@p2@ identifier pdev; @@ void rtsx_usb_sdmmc_drv_remove(struct platform_device *pdev) { ... -Return(); }
Then another rule to remove the others:
@p2@ identifier pdev; @@ void rtsx_usb_sdmmc_drv_remove(struct platform_device *pdev) { <... -Return(); +return; ...> }
julia
> -------->8-------- > > results in > > -------->8-------- > $ /usr/bin/spatch --debug -D patch --very-quiet --cocci-file scripts/coccinelle/api/test.cocci --patch . --dir drivers/mmc/host/rtsx_usb_sdmmc.c -I ./arch/x86/include -I ./arch/x86/include/generated -I ./include -I ./arch/x86/include/uapi -I ./arch/x86/include/generated/uapi -I ./include/uapi -I ./include/generated/uapi --include ./include/linux/compiler-version.h --include ./include/linux/kconfig.h --jobs 4 --chunksize 1 > diff -u -p a/drivers/mmc/host/rtsx_usb_sdmmc.c b/drivers/mmc/host/rtsx_usb_sdmmc.c > --- a/drivers/mmc/host/rtsx_usb_sdmmc.c > +++ b/drivers/mmc/host/rtsx_usb_sdmmc.c > @@ -1385,7 +1385,7 @@ static int rtsx_usb_sdmmc_drv_remove(str > struct mmc_host *mmc; > > if (!host) > - return 0; > + Return(); > > mmc = host->mmc; > host->host_removal = true; > @@ -1416,7 +1416,7 @@ static int rtsx_usb_sdmmc_drv_remove(str > dev_dbg(&(pdev->dev), > ": Realtek USB SD/MMC module has been removed\n"); > > - return 0; > + Return(); > } > > #ifdef CONFIG_PM > -------->8-------- > > Adding --debug doesn't give any hints. > > (And if I add another hunk inbeetween removing Return at the end of the > function there is no effect either.) > > Do I need to split that in two spatches to make coccinelle cooperate? > > (If it matters, this is coccinelle as shipped by Debian, Version > 1.1.1.deb-2) > > Best regards > Uwe > > -- > Pengutronix e.K. | Uwe Kleine-König | > Industrial Linux Solutions | https://www.pengutronix.de/ | >
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