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[98.183.112.25]) by smtp.gmail.com with ESMTPSA id 46e09a7af769-7271f7c5ba8sm2752929a34.32.2025.02.20.09.32.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 20 Feb 2025 09:32:12 -0800 (PST) Message-ID: <0084eef7-3831-4e62-acf1-6c2dc0e15dd1@baylibre.com> Date: Thu, 20 Feb 2025 11:32:10 -0600 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 05/15] bus: ts-nbus: use bitmap_get_value8() To: Simon Horman Cc: Linus Walleij , Bartosz Golaszewski , Andy Shevchenko , Geert Uytterhoeven , Lars-Peter Clausen , Michael Hennerich , Jonathan Cameron , Ulf Hansson , Peter Rosin , Andrew Lunn , Heiner Kallweit , Russell King , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Vinod Koul , Kishon Vijay Abraham I , =?UTF-8?Q?Nuno_S=C3=A1?= , Liam Girdwood , Mark Brown , Jaroslav Kysela , Takashi Iwai , linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, linux-mmc@vger.kernel.org, netdev@vger.kernel.org, linux-phy@lists.infradead.org, linux-sound@vger.kernel.org, Andy Shevchenko References: <20250210-gpio-set-array-helper-v3-0-d6a673674da8@baylibre.com> <20250210-gpio-set-array-helper-v3-5-d6a673674da8@baylibre.com> <20250220101742.GR1615191@kernel.org> Content-Language: en-US From: David Lechner In-Reply-To: <20250220101742.GR1615191@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 2/20/25 4:17 AM, Simon Horman wrote: > On Mon, Feb 10, 2025 at 04:33:31PM -0600, David Lechner wrote: >> Use bitmap_get_value8() instead of accessing the bitmap directly. >> >> Accessing the bitmap directly is not considered good practice. We now >> have a helper function that can be used instead, so let's use it. >> >> Suggested-by: Andy Shevchenko > u> Signed-off-by: David Lechner >> --- >> drivers/bus/ts-nbus.c | 5 +++-- >> 1 file changed, 3 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/bus/ts-nbus.c b/drivers/bus/ts-nbus.c >> index b4c9308caf0647a3261071d9527fffce77784af2..beac67f3b820377f8bb1fc4f4ee77e15ee240834 100644 >> --- a/drivers/bus/ts-nbus.c >> +++ b/drivers/bus/ts-nbus.c >> @@ -10,6 +10,7 @@ >> * TS-4600 SoM. >> */ >> >> +#include >> #include >> #include >> #include >> @@ -107,7 +108,7 @@ static void ts_nbus_reset_bus(struct ts_nbus *ts_nbus) >> { >> DECLARE_BITMAP(values, 8); >> >> - values[0] = 0; >> + bitmap_set_value8(values, byte, 0); > > Hi David, > > byte doesn't appear to exist in the scope of this function. > > I tried this: > > bitmap_set_value8(values, 0, 8); > > But when compiling with GCC 14.2.0 I see warnings that values > is used uninitialised - bitmap_set_value8() appears to rely on > it being so. Ah yes, I see the problem (I don't think this driver compiles with allmodconfig so the compiler didn't catch it for me). > > CC drivers/bus/ts-nbus.o > In file included from drivers/bus/ts-nbus.c:13: > In function ‘bitmap_write’, > inlined from ‘ts_nbus_reset_bus’ at drivers/bus/ts-nbus.c:111:2: > ./include/linux/bitmap.h:818:12: error: ‘values’ is used uninitialized [-Werror=uninitialized] > 818 | map[index] &= (fit ? (~(mask << offset)) : ~BITMAP_FIRST_WORD_MASK(start)); > | ~~~^~~~~~~ > In file included from ./include/linux/kasan-checks.h:5, > from ./include/asm-generic/rwonce.h:26, > from ./arch/x86/include/generated/asm/rwonce.h:1, > from ./include/linux/compiler.h:344, > from ./include/linux/build_bug.h:5, > from ./include/linux/bits.h:22, > from ./include/linux/bitops.h:6, > from ./include/linux/bitmap.h:8: > drivers/bus/ts-nbus.c: In function ‘ts_nbus_reset_bus’: > drivers/bus/ts-nbus.c:109:24: note: ‘values’ declared here > 109 | DECLARE_BITMAP(values, 8); > | ^~~~~~ > ./include/linux/types.h:11:23: note: in definition of macro ‘DECLARE_BITMAP’ > 11 | unsigned long name[BITS_TO_LONGS(bits)] > | ^~~~ > > >> >> gpiod_multi_set_value_cansleep(ts_nbus->data, values); >> gpiod_set_value_cansleep(ts_nbus->csn, 0); >> @@ -151,7 +152,7 @@ static void ts_nbus_write_byte(struct ts_nbus *ts_nbus, u8 byte) >> { >> DECLARE_BITMAP(values, 8); We can fix by zero-initialing the bitmap. DECLARE_BITMAP(values, 8) = { }; Would you like me to send a new version of the patch? >> >> - values[0] = byte; >> + bitmap_set_value8(values, byte, 8); >> >> gpiod_multi_set_value_cansleep(ts_nbus->data, values); >> } >> >> -- >> 2.43.0 >>