From: Dmitry Osipenko <digetx@gmail.com>
To: Thierry Reding <thierry.reding@gmail.com>,
Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: "Jonathan Hunter" <jonathanh@nvidia.com>,
"Laxman Dewangan" <ldewangan@nvidia.com>,
"Wolfram Sang" <wsa@the-dreams.de>,
"Michał Mirosław" <mirq-linux@rere.qmqm.pl>,
linux-i2c <linux-i2c@vger.kernel.org>,
linux-tegra@vger.kernel.org,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v7 27/34] i2c: tegra: Check errors for both positive and negative values
Date: Mon, 21 Sep 2020 17:13:34 +0300 [thread overview]
Message-ID: <0d18c64c-8765-a840-f963-ba6a205f0e6a@gmail.com> (raw)
In-Reply-To: <20200921112425.GK3950626@ulmo>
21.09.2020 14:24, Thierry Reding пишет:
> On Thu, Sep 17, 2020 at 04:50:06PM +0300, Andy Shevchenko wrote:
>> On Thu, Sep 17, 2020 at 3:09 PM Thierry Reding <thierry.reding@gmail.com> wrote:
>>> On Wed, Sep 09, 2020 at 01:39:59AM +0300, Dmitry Osipenko wrote:
>>
>>> Why? All of these functions "return 0 on success or a negative error
>>> code on failure", don't they?
>>
>> And what is the point of having ' < 0' in all those cases?
>
> It's explicitly checking for the documented error cases. And you'll
> occasionally have a function that can return non-zero on success.
> Testing for < 0 is the safest way to check for failure in the majority
> of cases.
If you're testing only for negative errors, then it means that you will
miss wrong positive errors, potentially setting machine on fire :) This
is not an often problem for kernel, but this is a problem that I
experienced with userspace more than one time.
Anyways, this patch also makes the errors checking consistent across the
whole driver and it makes the code look cleaner, so I'll prefer to keep
this patch as-is.
next prev parent reply other threads:[~2020-09-21 14:13 UTC|newest]
Thread overview: 146+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-08 22:39 [PATCH v7 00/34] Improvements for Tegra I2C driver Dmitry Osipenko
2020-09-08 22:39 ` [PATCH v7 01/34] i2c: tegra: Make tegra_i2c_flush_fifos() usable in atomic transfer Dmitry Osipenko
2020-09-17 11:10 ` Thierry Reding
2020-09-17 14:57 ` Dmitry Osipenko
2020-09-21 10:18 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 02/34] i2c: tegra: Add missing pm_runtime_put() Dmitry Osipenko
2020-09-17 11:12 ` Thierry Reding
2020-09-21 10:18 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 03/34] i2c: tegra: Handle potential error of tegra_i2c_flush_fifos() Dmitry Osipenko
2020-09-17 11:13 ` Thierry Reding
2020-09-21 10:18 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 04/34] i2c: tegra: Mask interrupt in tegra_i2c_issue_bus_clear() Dmitry Osipenko
2020-09-17 11:18 ` Thierry Reding
2020-09-21 10:18 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 05/34] i2c: tegra: Initialize div-clk rate unconditionally Dmitry Osipenko
2020-09-17 11:20 ` Thierry Reding
2020-09-21 10:18 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 06/34] i2c: tegra: Remove i2c_dev.clk_divisor_non_hs_mode member Dmitry Osipenko
2020-09-17 11:25 ` Thierry Reding
2020-09-17 15:27 ` Dmitry Osipenko
2020-09-21 10:49 ` Thierry Reding
2020-09-21 10:18 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 07/34] i2c: tegra: Runtime PM always available on Tegra Dmitry Osipenko
2020-09-17 11:26 ` Thierry Reding
2020-09-21 10:18 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 08/34] i2c: tegra: Remove error message used for devm_request_irq() failure Dmitry Osipenko
2020-09-17 11:28 ` Thierry Reding
2020-09-17 14:59 ` Dmitry Osipenko
2020-09-21 10:57 ` Thierry Reding
2020-09-21 10:18 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 09/34] i2c: tegra: Use reset_control_reset() Dmitry Osipenko
2020-09-17 12:36 ` Thierry Reding
2020-09-21 10:19 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 10/34] i2c: tegra: Use devm_platform_get_and_ioremap_resource() Dmitry Osipenko
2020-09-17 11:31 ` Thierry Reding
2020-09-21 10:19 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 11/34] i2c: tegra: Use platform_get_irq() Dmitry Osipenko
2020-09-17 11:31 ` Thierry Reding
2020-09-21 10:19 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 12/34] i2c: tegra: Use clk-bulk helpers Dmitry Osipenko
2020-09-17 11:38 ` Thierry Reding
2020-09-17 13:54 ` Andy Shevchenko
2020-09-21 11:01 ` Thierry Reding
2020-09-21 11:15 ` Andy Shevchenko
2020-09-21 11:53 ` Thierry Reding
2020-09-17 15:01 ` Dmitry Osipenko
2020-09-21 11:08 ` Thierry Reding
2020-09-21 11:12 ` Thierry Reding
2020-09-21 14:44 ` Dmitry Osipenko
2020-09-21 10:19 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 13/34] i2c: tegra: Move out all device-tree parsing into tegra_i2c_parse_dt() Dmitry Osipenko
2020-09-17 11:35 ` Thierry Reding
2020-09-21 10:19 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 14/34] i2c: tegra: Clean up probe function Dmitry Osipenko
2020-09-17 12:37 ` Thierry Reding
2020-09-17 13:46 ` Andy Shevchenko
2020-09-21 11:15 ` Thierry Reding
2020-09-17 15:02 ` Dmitry Osipenko
2020-09-21 11:17 ` Thierry Reding
2020-09-21 10:19 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 15/34] i2c: tegra: Reorder location of functions in the code Dmitry Osipenko
2020-09-17 12:38 ` Thierry Reding
2020-09-21 10:19 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 16/34] i2c: tegra: Clean up variable types Dmitry Osipenko
2020-09-17 12:39 ` Thierry Reding
2020-09-21 10:19 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 17/34] i2c: tegra: Remove outdated barrier() Dmitry Osipenko
2020-09-17 12:39 ` Thierry Reding
2020-09-21 10:19 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 18/34] i2c: tegra: Remove likely/unlikely from the code Dmitry Osipenko
2020-09-17 12:41 ` Thierry Reding
2020-09-21 10:19 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 19/34] i2c: tegra: Remove redundant check in tegra_i2c_issue_bus_clear() Dmitry Osipenko
2020-09-17 12:42 ` Thierry Reding
2020-09-21 10:19 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 20/34] i2c: tegra: Remove "dma" variable from tegra_i2c_xfer_msg() Dmitry Osipenko
2020-09-17 11:44 ` Thierry Reding
2020-09-21 10:19 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 21/34] i2c: tegra: Don't fall back to PIO mode if DMA configuration fails Dmitry Osipenko
2020-09-17 11:47 ` Thierry Reding
2020-09-17 15:03 ` Dmitry Osipenko
2020-09-21 11:21 ` Thierry Reding
2020-09-21 10:19 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 22/34] i2c: tegra: Rename wait/poll functions Dmitry Osipenko
2020-09-17 11:48 ` Thierry Reding
2020-09-21 10:19 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 23/34] i2c: tegra: Factor out error recovery from tegra_i2c_xfer_msg() Dmitry Osipenko
2020-09-17 11:49 ` Thierry Reding
2020-09-21 10:20 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 24/34] i2c: tegra: Factor out packet header setup " Dmitry Osipenko
2020-09-17 11:51 ` Thierry Reding
2020-09-21 10:20 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 25/34] i2c: tegra: Factor out register polling into separate function Dmitry Osipenko
2020-09-17 11:58 ` Thierry Reding
2020-09-17 15:05 ` Dmitry Osipenko
2020-09-21 11:22 ` Thierry Reding
2020-09-21 10:20 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 26/34] i2c: tegra: Factor out hardware initialization " Dmitry Osipenko
2020-09-17 12:06 ` Thierry Reding
2020-09-21 10:20 ` Thierry Reding
2020-09-08 22:39 ` [PATCH v7 27/34] i2c: tegra: Check errors for both positive and negative values Dmitry Osipenko
2020-09-17 12:09 ` Thierry Reding
2020-09-17 13:50 ` Andy Shevchenko
2020-09-21 11:24 ` Thierry Reding
2020-09-21 14:13 ` Dmitry Osipenko [this message]
2020-09-21 10:20 ` Thierry Reding
2020-09-08 22:40 ` [PATCH v7 28/34] i2c: tegra: Consolidate error handling in tegra_i2c_xfer_msg() Dmitry Osipenko
2020-09-17 12:12 ` Thierry Reding
2020-09-21 10:20 ` Thierry Reding
2020-09-08 22:40 ` [PATCH v7 29/34] i2c: tegra: Improve formatting of variables Dmitry Osipenko
2020-09-17 12:16 ` Thierry Reding
2020-09-17 15:13 ` Dmitry Osipenko
2020-09-21 11:28 ` Thierry Reding
2020-09-21 10:20 ` Thierry Reding
2020-09-08 22:40 ` [PATCH v7 30/34] i2c: tegra: Clean up variable names Dmitry Osipenko
2020-09-17 12:21 ` Thierry Reding
2020-09-17 15:43 ` Dmitry Osipenko
2020-09-21 11:40 ` Thierry Reding
2020-09-21 15:18 ` Dmitry Osipenko
2020-09-21 15:50 ` Thierry Reding
2020-09-21 16:05 ` Dmitry Osipenko
2020-09-21 10:20 ` Thierry Reding
2020-09-08 22:40 ` [PATCH v7 31/34] i2c: tegra: Clean up printk messages Dmitry Osipenko
2020-09-17 12:22 ` Thierry Reding
2020-09-21 10:20 ` Thierry Reding
2020-09-08 22:40 ` [PATCH v7 32/34] i2c: tegra: Clean up and improve comments Dmitry Osipenko
2020-09-17 12:32 ` Thierry Reding
2020-09-17 15:02 ` Dmitry Osipenko
2020-09-17 15:17 ` Dmitry Osipenko
2020-09-21 11:43 ` Thierry Reding
2020-09-21 11:44 ` Thierry Reding
2020-09-21 10:20 ` Thierry Reding
2020-09-08 22:40 ` [PATCH v7 33/34] i2c: tegra: Clean up whitespaces, newlines and indentation Dmitry Osipenko
2020-09-17 12:35 ` Thierry Reding
2020-09-21 10:20 ` Thierry Reding
2020-09-08 22:40 ` [PATCH v7 34/34] i2c: tegra: Improve driver module description Dmitry Osipenko
2020-09-17 12:35 ` Thierry Reding
2020-09-21 10:20 ` Thierry Reding
2020-09-09 9:11 ` [PATCH v7 00/34] Improvements for Tegra I2C driver Andy Shevchenko
2020-09-09 15:36 ` Dmitry Osipenko
2020-09-09 15:49 ` Wolfram Sang
2020-09-09 17:39 ` Dmitry Osipenko
2020-09-17 12:44 ` Thierry Reding
2020-09-21 9:12 ` Wolfram Sang
2020-09-21 10:18 ` Thierry Reding
2020-09-21 10:42 ` Thierry Reding
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