netdev - Re: [PATCH v2] bpf: silence warnings when building kernel/bpf/core.c with W=1

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Message-ID: <20160801150955.GA99277@ast-mbp.thefacebook.com>
Date:	Mon, 1 Aug 2016 08:09:57 -0700
From:	Alexei Starovoitov <alexei.starovoitov@...il.com>
To:	Valdis.Kletnieks@...edu
Cc:	Alexei Starovoitov <ast@...nel.org>, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>
Subject: Re: [PATCH v2] bpf: silence warnings when building kernel/bpf/core.c
 with W=1

On Mon, Aug 01, 2016 at 01:18:43AM -0400, Valdis.Kletnieks@...edu wrote:
> On Sun, 31 Jul 2016 21:42:22 -0700, Alexei Starovoitov said:
> 
> > and at least 2 other such patches for other files...
> > Is there a single warning where -Woverride-init was useful?
> > May be worth disabling this warning for the whole build?
> 
> There's a few other cases that *aren't* the "define the array to zero
> and then build the entries from a list" form.
> 
> In particular, there's still 3 odd complaints:
> 
> drivers/ata/ahci.c:
> drivers/ata/ahci.h:393:16: warning: initialized field overwritten [-Woverride-in
> it]
>   .can_queue  = AHCI_MAX_CMDS - 1,
> 
> drivers/block/drbd/drbd_main.c:
> drivers/block/drbd/drbd_main.c:3767:22: warning: initialized field overwritten [
> -Woverride-init]
>    [P_RETRY_WRITE]  = "retry_write",
> 
> arch/x86/kernel/cpu/common.c:
> ./arch/x86/include/asm/page_64_types.h:22:21: warning: initialized field overwri
> tten [-Woverride-init]
>  #define DEBUG_STKSZ (PAGE_SIZE << DEBUG_STACK_ORDER)
> 
> The point of these patches is to make -Woverride-init *useful* - you'll never
> spot 3 warnings in a flood of over 9,000 understood-and-ignored warnings.
> 
> Get rid of the 9,000 understood-and-ignored warnings, and then things that
> probably *should* be looked at can be noticed.

I don't think it makes sense to play kernel whack-a-warning in a hope that
particular warning will find something useful.
Please show few cases where it actually found a real issue, otherwise
just disable it for all.