From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: George Hilliard <thirtythreeforty@gmail.com>
Cc: linux-mips@linux-mips.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 06/11] staging: mt7621-mmc: Initialize completions a single time during probe
Date: Wed, 20 Mar 2019 08:22:06 +0100 [thread overview]
Message-ID: <20190320072206.GB1914@kroah.com> (raw)
In-Reply-To: <20190319022012.11051-7-thirtythreeforty@gmail.com>
On Mon, Mar 18, 2019 at 08:20:07PM -0600, George Hilliard wrote:
> The module was initializing completions whenever it was going to wait on
> them, and not when the completion was allocated. This is incorrect
> according to the completion docs:
>
> Calling init_completion() on the same completion object twice is
> most likely a bug [...]
>
> Re-initialization is also unnecessary because the module never uses
> complete_all(). Fix this by only ever initializing the completion a
> single time.
>
> Signed-off-by: George Hilliard <thirtythreeforty@gmail.com>
> ---
> drivers/staging/mt7621-mmc/sd.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/staging/mt7621-mmc/sd.c b/drivers/staging/mt7621-mmc/sd.c
> index 89fbc0a1dec7..c272aa780719 100644
> --- a/drivers/staging/mt7621-mmc/sd.c
> +++ b/drivers/staging/mt7621-mmc/sd.c
> @@ -467,7 +467,9 @@ static unsigned int msdc_command_start(struct msdc_host *host,
> host->cmd = cmd;
> host->cmd_rsp = resp;
>
> - init_completion(&host->cmd_done);
> + // The completion should have been consumed by the previous command
> + // response handler, because the mmc requests should be serialized
> + BUG_ON(completion_done(&host->cmd_done));
Adding new BUG_ON() calls is not ok. That crashes the machine and will
break everyone. If this really is a potential error that could happen,
then handle it. If not, then do not even put this there, it's not
needed.
All of the BUG_ON() entries need to be removed in the end from this code
anyway.
thanks,
greg k-h
next prev parent reply other threads:[~2019-03-20 7:22 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190319022012.11051-1-thirtythreeforty@gmail.com>
2019-03-19 2:20 ` [PATCH v2 01/11] staging: mt7621-mmc: fix unused variable compiler warning George Hilliard
2019-03-19 2:20 ` [PATCH v2 02/11] staging: mt7621-mmc: Remove obsolete comments and variables George Hilliard
2019-03-19 2:20 ` [PATCH v2 03/11] staging: mt7621-mmc: Fix warning when reloading module with debug msgs enabled George Hilliard
2019-03-20 7:19 ` Greg Kroah-Hartman
2019-03-19 2:20 ` [PATCH v2 04/11] staging: mt7621-mmc: Use pinctrl subsystem to select SDXC pin mode George Hilliard
2019-03-19 2:20 ` [PATCH v2 05/11] staging: mt7621-mmc: Bill the caller for I/O time George Hilliard
2019-03-19 2:20 ` [PATCH v2 06/11] staging: mt7621-mmc: Initialize completions a single time during probe George Hilliard
2019-03-20 7:22 ` Greg Kroah-Hartman [this message]
2019-03-19 2:20 ` [PATCH v2 07/11] staging: mt7621-mmc: Check for nonzero number of scatterlist entries George Hilliard
2019-03-20 7:22 ` Greg Kroah-Hartman
2019-03-19 2:20 ` [PATCH v2 08/11] staging: mt7621-mmc: Remove redundant host->mmc->f_max write George Hilliard
2019-03-19 2:20 ` [PATCH v2 09/11] staging: mt7621-mmc: Immediately notify mmc layer of card change detection George Hilliard
2019-03-19 2:20 ` [PATCH v2 10/11] staging: mt7621-mmc: Fix BRUST -> BURST typo George Hilliard
2019-03-19 2:20 ` [PATCH v2 11/11] staging: mt7621-mmc: Only unmap_sg if mapped George Hilliard
2019-03-20 7:26 ` your mail Greg Kroah-Hartman
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