linux-kernel - [PATCH v2 09/10] mfd: 88pm860x-i2c: switch to i2c_lock_bus(..., I2C_LOCK

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20180620051803.12206-10-peda@axentia.se>
Date:   Wed, 20 Jun 2018 07:18:02 +0200
From:   Peter Rosin <peda@...ntia.se>
To:     linux-kernel@...r.kernel.org
Cc:     Peter Rosin <peda@...ntia.se>, Peter Huewe <peterhuewe@....de>,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        Jason Gunthorpe <jgg@...pe.ca>, Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Brian Norris <computersforpeace@...il.com>,
        Gregory Fong <gregory.0xf0@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        bcm-kernel-feedback-list@...adcom.com,
        Sekhar Nori <nsekhar@...com>,
        Kevin Hilman <khilman@...nel.org>,
        Haavard Skinnemoen <hskinnemoen@...il.com>,
        Kukjin Kim <kgene@...nel.org>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Orson Zhai <orsonzhai@...il.com>,
        Baolin Wang <baolin.wang@...aro.org>,
        Chunyan Zhang <zhang.lyra@...il.com>,
        Wolfram Sang <wsa@...-dreams.de>,
        Guenter Roeck <linux@...ck-us.net>, Crt Mori <cmo@...exis.com>,
        Jonathan Cameron <jic23@...nel.org>,
        Hartmut Knaack <knaack.h@....de>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Peter Meerwald-Stadler <pmeerw@...erw.net>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Antti Palosaari <crope@....fi>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Michael Krufky <mkrufky@...uxtv.org>,
        Lee Jones <lee.jones@...aro.org>,
        linux-integrity@...r.kernel.org, linux-i2c@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, linux-iio@...r.kernel.org,
        linux-input@...r.kernel.org, linux-media@...r.kernel.org
Subject: [PATCH v2 09/10] mfd: 88pm860x-i2c: switch to i2c_lock_bus(..., I2C_LOCK_SEGMENT)

Locking the root adapter for __i2c_transfer will deadlock if the
device sits behind a mux-locked I2C mux. Switch to the finer-grained
i2c_lock_bus with the I2C_LOCK_SEGMENT flag. If the device does not
sit behind a mux-locked mux, the two locking variants are equivalent.

Signed-off-by: Peter Rosin <peda@...ntia.se>
---
 drivers/mfd/88pm860x-i2c.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/mfd/88pm860x-i2c.c b/drivers/mfd/88pm860x-i2c.c
index 84e313107233..7b9052ea7413 100644
--- a/drivers/mfd/88pm860x-i2c.c
+++ b/drivers/mfd/88pm860x-i2c.c
@@ -146,14 +146,14 @@ int pm860x_page_reg_write(struct i2c_client *i2c, int reg,
 	unsigned char zero;
 	int ret;
 
-	i2c_lock_adapter(i2c->adapter);
+	i2c_lock_bus(i2c->adapter, I2C_LOCK_SEGMENT);
 	read_device(i2c, 0xFA, 0, &zero);
 	read_device(i2c, 0xFB, 0, &zero);
 	read_device(i2c, 0xFF, 0, &zero);
 	ret = write_device(i2c, reg, 1, &data);
 	read_device(i2c, 0xFE, 0, &zero);
 	read_device(i2c, 0xFC, 0, &zero);
-	i2c_unlock_adapter(i2c->adapter);
+	i2c_unlock_bus(i2c->adapter, I2C_LOCK_SEGMENT);
 	return ret;
 }
 EXPORT_SYMBOL(pm860x_page_reg_write);
@@ -164,14 +164,14 @@ int pm860x_page_bulk_read(struct i2c_client *i2c, int reg,
 	unsigned char zero = 0;
 	int ret;
 
-	i2c_lock_adapter(i2c->adapter);
+	i2c_lock_bus(i2c->adapter, I2C_LOCK_SEGMENT);
 	read_device(i2c, 0xfa, 0, &zero);
 	read_device(i2c, 0xfb, 0, &zero);
 	read_device(i2c, 0xff, 0, &zero);
 	ret = read_device(i2c, reg, count, buf);
 	read_device(i2c, 0xFE, 0, &zero);
 	read_device(i2c, 0xFC, 0, &zero);
-	i2c_unlock_adapter(i2c->adapter);
+	i2c_unlock_bus(i2c->adapter, I2C_LOCK_SEGMENT);
 	return ret;
 }
 EXPORT_SYMBOL(pm860x_page_bulk_read);
-- 
2.11.0