Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756021AbcCXOqh (ORCPT ); Thu, 24 Mar 2016 10:46:37 -0400 Received: from mail-wm0-f44.google.com ([74.125.82.44]:32817 "EHLO mail-wm0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752041AbcCXOqQ (ORCPT ); Thu, 24 Mar 2016 10:46:16 -0400 From: Bartosz Golaszewski To: Wolfram Sang , linux-i2c , LKML Cc: Andrew Lunn , Bartosz Golaszewski Subject: [PATCH 04/13] eeprom: at24: make locking more fine-grained Date: Thu, 24 Mar 2016 15:45:58 +0100 Message-Id: <1458830767-23816-5-git-send-email-bgolaszewski@baylibre.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1458830767-23816-1-git-send-email-bgolaszewski@baylibre.com> References: <1458830767-23816-1-git-send-email-bgolaszewski@baylibre.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2730 Lines: 102 The only field in struct at24_data that needs locking in the module code is u8 *writebuf. Other data is already protected by i2c core. Rename the lock in at24_data to wrbuf_lock and only use it where writebuf is accessed. Signed-off-by: Bartosz Golaszewski --- drivers/misc/eeprom/at24.c | 28 +++++----------------------- 1 file changed, 5 insertions(+), 23 deletions(-) diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c index 744c526..9e01428 100644 --- a/drivers/misc/eeprom/at24.c +++ b/drivers/misc/eeprom/at24.c @@ -59,13 +59,8 @@ struct at24_data { int use_smbus; int use_smbus_write; - /* - * Lock protects against activities from other Linux tasks, - * but not from changes by other I2C masters. - */ - struct mutex lock; - u8 *writebuf; + struct mutex wrbuf_lock; unsigned write_max; unsigned num_addresses; @@ -260,12 +255,6 @@ static ssize_t at24_read(struct at24_data *at24, if (unlikely(!count)) return count; - /* - * Read data from chip, protecting against concurrent updates - * from this host, but not from other I2C masters. - */ - mutex_lock(&at24->lock); - while (count) { ssize_t status; @@ -281,8 +270,6 @@ static ssize_t at24_read(struct at24_data *at24, retval += status; } - mutex_unlock(&at24->lock); - return retval; } @@ -322,6 +309,8 @@ static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf, msg.addr = client->addr; msg.flags = 0; + mutex_lock(&at24->wrbuf_lock); + /* msg.buf is u8 and casts will mask the values */ msg.buf = at24->writebuf; if (at24->chip.flags & AT24_FLAG_ADDR16) @@ -356,6 +345,7 @@ static ssize_t at24_eeprom_write(struct at24_data *at24, const char *buf, status = count; } else { status = i2c_transfer(client->adapter, &msg, 1); + mutex_unlock(&at24->wrbuf_lock); if (status == 1) status = count; } @@ -380,12 +370,6 @@ static ssize_t at24_write(struct at24_data *at24, const char *buf, loff_t off, if (unlikely(!count)) return count; - /* - * Write data to chip, protecting against concurrent updates - * from this host, but not from other I2C masters. - */ - mutex_lock(&at24->lock); - while (count) { ssize_t status; @@ -401,8 +385,6 @@ static ssize_t at24_write(struct at24_data *at24, const char *buf, loff_t off, retval += status; } - mutex_unlock(&at24->lock); - return retval; } @@ -566,7 +548,7 @@ static int at24_probe(struct i2c_client *client, const struct i2c_device_id *id) if (!at24) return -ENOMEM; - mutex_init(&at24->lock); + mutex_init(&at24->wrbuf_lock); at24->use_smbus = use_smbus; at24->use_smbus_write = use_smbus_write; at24->chip = chip; -- 2.7.4