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Date:   Sun, 27 Oct 2019 16:54:14 +0000
From:   Jonathan Cameron <jic23@kernel.org>
To:     Laura Abbott <labbott@redhat.com>
Cc:     Jiri Olsa <jolsa@kernel.org>, Hartmut Knaack <knaack.h@gmx.de>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
        linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org,
        Masahiro Yamada <yamada.masahiro@socionext.com>
Subject: Re: [PATCH] tools: iio: Correctly add make dependency for iio_utils
Message-ID: <20191027165414.3e4c3530@archlinux>
In-Reply-To: <20191018172908.3761-1-labbott@redhat.com>
References: <20191018172908.3761-1-labbott@redhat.com>
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On Fri, 18 Oct 2019 13:29:08 -0400
Laura Abbott <labbott@redhat.com> wrote:

> iio tools fail to build correctly with make parallelization:
> 
> $ make -s -j24
> fixdep: error opening depfile: ./.iio_utils.o.d: No such file or directory
> make[1]: *** [/home/labbott/linux_upstream/tools/build/Makefile.build:96: iio_utils.o] Error 2
> make: *** [Makefile:43: iio_event_monitor-in.o] Error 2
> make: *** Waiting for unfinished jobs....
> 
> This is because iio_utils.o is used across multiple targets.
> Fix this by making iio_utils.o a proper dependency.
> 
> Signed-off-by: Laura Abbott <labbott@redhat.com>
This looks fine to me, but my Makefile foo is decidedly limited. 
Anyone else want to give a view?

It seems sensible to backport this to stable as it seems low
risk and will avoid some odd issues for distros.

Thanks,

Jonathan
> ---
> I realize that we don't really need the parallelization for tools
> because it's so small but when building with the distro we want to use
> the same make command and -j wherever possible.
> 
> This same issue also appears in the gpio tools so if this looks like an
> okay approach I'll fix it there as well.
> ---
>  tools/iio/Build    |  1 +
>  tools/iio/Makefile | 10 +++++++---
>  2 files changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/iio/Build b/tools/iio/Build
> index f74cbda64710..8d0f3af3723f 100644
> --- a/tools/iio/Build
> +++ b/tools/iio/Build
> @@ -1,3 +1,4 @@
> +iio_utils-y += iio_utils.o
>  lsiio-y += lsiio.o iio_utils.o
>  iio_event_monitor-y += iio_event_monitor.o iio_utils.o
>  iio_generic_buffer-y += iio_generic_buffer.o iio_utils.o
> diff --git a/tools/iio/Makefile b/tools/iio/Makefile
> index e22378dba244..3de763d9ab70 100644
> --- a/tools/iio/Makefile
> +++ b/tools/iio/Makefile
> @@ -32,20 +32,24 @@ $(OUTPUT)include/linux/iio: ../../include/uapi/linux/iio
>  
>  prepare: $(OUTPUT)include/linux/iio
>  
> +IIO_UTILS_IN := $(OUTPUT)iio_utils-in.o
> +$(IIO_UTILS_IN): prepare FORCE
> +	$(Q)$(MAKE) $(build)=iio_utils
> +
>  LSIIO_IN := $(OUTPUT)lsiio-in.o
> -$(LSIIO_IN): prepare FORCE
> +$(LSIIO_IN): prepare FORCE $(OUTPUT)iio_utils-in.o
>  	$(Q)$(MAKE) $(build)=lsiio
>  $(OUTPUT)lsiio: $(LSIIO_IN)
>  	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
>  
>  IIO_EVENT_MONITOR_IN := $(OUTPUT)iio_event_monitor-in.o
> -$(IIO_EVENT_MONITOR_IN): prepare FORCE
> +$(IIO_EVENT_MONITOR_IN): prepare FORCE $(OUTPUT)iio_utils-in.o
>  	$(Q)$(MAKE) $(build)=iio_event_monitor
>  $(OUTPUT)iio_event_monitor: $(IIO_EVENT_MONITOR_IN)
>  	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
>  
>  IIO_GENERIC_BUFFER_IN := $(OUTPUT)iio_generic_buffer-in.o
> -$(IIO_GENERIC_BUFFER_IN): prepare FORCE
> +$(IIO_GENERIC_BUFFER_IN): prepare FORCE $(OUTPUT)iio_utils-in.o
>  	$(Q)$(MAKE) $(build)=iio_generic_buffer
>  $(OUTPUT)iio_generic_buffer: $(IIO_GENERIC_BUFFER_IN)
>  	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@