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From: "Carlo Marcelo Arenas Belón" <carenas@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Johannes Schindelin <Johannes.Schindelin@gmx.de>,
	git@vger.kernel.org, Michael J Gruber <git@grubix.eu>
Subject: Re: [PATCH] http.c: clear the 'finished' member once we are done with it
Date: Tue, 24 May 2022 13:16:39 -0700	[thread overview]
Message-ID: <20220524201639.2gucdkzponddk5qt@carlos-mbp.lan> (raw)
In-Reply-To: <xmqqleuqj1gy.fsf@gitster.g>

On Tue, May 24, 2022 at 10:15:57AM -0700, Junio C Hamano wrote:
> 
> I _think_ we can even get away by not doing anything to
> slot->finished at the end of run_active_slot(), as we are not
> multi-threaded and the callee only returns to the caller, but if it
> helps pleasing the warning compiler, I'd prefer the simplest
> workaround, perhaps with an unconditional clearing there?

Assuming that some overly clever compiler might optimize that out (either
because it might think it is Undefined Behaviour or for other unknown
reasons) then Ævar's version would be better for clearing the "warning".

But your patch fixed the "bug" that a probably overeager compiler was
"detecting".

> What did I miss?  I must be missing something, as I can explain how
> the current "(*slot->finished) = 1" with "while (finished)"
> correctly works, but I cannot quite explain why the original "while
> (slot->in_use)" would not, which is annoying.

My guess is that there is a curl version somewhere that is patched to use
threads more extensible than upstream and where this code is stil needed.
I think it is also safe to assume (like you did) that this is a 16 year bug
that was already fixed and reverting that code would be an alternative too.

Carlo

  reply	other threads:[~2022-05-24 20:16 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-06 18:04 [PATCH 0/2] quell a few gcc warnings Michael J Gruber
2022-05-06 18:04 ` [PATCH 1/2] dir.c: avoid gcc warning Michael J Gruber
2022-05-06 20:21   ` Junio C Hamano
2022-05-09 15:58     ` Taylor Blau
2022-05-07  6:14   ` Carlo Marcelo Arenas Belón
2022-05-06 18:04 ` [PATCH 2/2] http.c: " Michael J Gruber
2022-05-06 20:22   ` Junio C Hamano
2022-05-06 21:17     ` [PATCH] http.c: clear the 'finished' member once we are done with it Junio C Hamano
2022-05-07  5:40       ` Carlo Marcelo Arenas Belón
2022-05-07 18:42         ` Junio C Hamano
2022-05-07 19:11           ` Carlo Arenas
2022-05-23 21:58       ` Johannes Schindelin
2022-05-23 22:58         ` Junio C Hamano
2022-05-23 23:36           ` Junio C Hamano
2022-05-23 23:41           ` Johannes Schindelin
2022-05-24  0:02             ` Junio C Hamano
2022-05-24  6:31               ` Daniel Stenberg
2022-05-24 10:57                 ` Johannes Schindelin
2022-05-24 17:45                 ` Junio C Hamano
2022-05-26 14:15                   ` Daniel Stenberg
2022-05-24 11:03               ` Johannes Schindelin
2022-05-24 17:15                 ` Junio C Hamano
2022-05-24 20:16                   ` Carlo Marcelo Arenas Belón [this message]
2022-05-24 20:45                     ` Ævar Arnfjörð Bjarmason
2022-05-24 22:34                       ` Junio C Hamano
2022-05-25  9:08                         ` Michael J Gruber
2022-05-25 13:27                         ` Ævar Arnfjörð Bjarmason
2022-05-24 22:16                     ` Junio C Hamano
2022-05-24 23:19                     ` Junio C Hamano
2022-05-25  2:02                       ` Carlo Arenas
2022-05-24 20:38                   ` Ævar Arnfjörð Bjarmason
2022-05-24 22:28                     ` Junio C Hamano
2022-05-25 10:07                       ` Johannes Schindelin
2022-05-25 16:40                         ` Junio C Hamano
2022-05-06 20:41   ` [PATCH 2/2] http.c: avoid gcc warning Carlo Marcelo Arenas Belón
2022-05-09 11:22 ` [PATCH] detect-compiler: make detection independent of locale Michael J Gruber
2022-05-09 15:52   ` Junio C Hamano
2022-05-09 15:59     ` rsbecker

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