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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: <Waldemar.Rymarkiewicz@tieto.com>
Cc: <linux-i2c@vger.kernel.org>, <arnd@arndb.de>,
	<sameo@linux.intel.com>, <linux-kernel@vger.kernel.org>,
	<hthebaud@insidefr.com>, <matti.j.aaltonen@nokia.com>
Subject: Re: [PATCH] NFC: Driver for Inside Secure MicroRead NFC chip
Date: Fri, 18 Mar 2011 15:12:19 +0000	[thread overview]
Message-ID: <20110318151219.7aedc765@lxorguk.ukuu.org.uk> (raw)
In-Reply-To: <99B09243E1A5DA4898CDD8B7001114481085881963@EXMB04.eu.tieto.com>

> >Would it not be lighter to use atomic bit ops ?
> 
> Do you mean  in order to remove rx_mutex? 
> 
> mutex_lock(&info->rx_mutex);
> atomic_set(info->irq_state ,1);
> mutex_unlock(&info->rx_mutex);
> 
> looks a bit strange. I still need the rx_mutex to protect irq_state while reading i2c.
> 
> 	mutex_lock(&info->rx_mutex);
> 	ret = i2c_master_recv(client, info->buf, info->buflen);
> 	info->irq_state = 0;
> 	mutex_unlock(&info->rx_mutex);
> 

I was thinking clear_bit/test_and_set_bit rather than atomic_t operations.

ie in the IRQ

	clear_bit(0, &info->irq_state);


in the main path

	if (test_and_set_bit(0, &info->state))
		i2c_master_recv(...)

but if the mutex is needed anyway it doesn't help make the code saner.

  parent reply	other threads:[~2011-03-18 15:12 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-18 10:40 Waldemar Rymarkiewicz
2011-03-18 10:40 ` Waldemar Rymarkiewicz
2011-03-18 11:03   ` Alan Cox
2011-03-18 15:00     ` Waldemar.Rymarkiewicz
2011-03-18 15:05       ` Arnd Bergmann
2011-03-18 15:12       ` Alan Cox [this message]
2011-03-18 15:15         ` Waldemar.Rymarkiewicz
2011-03-18 11:49   ` Wolfram Sang
2011-03-18 15:08     ` Waldemar.Rymarkiewicz
2011-03-18 15:31       ` Mark Brown
2011-03-18 16:43     ` Waldemar.Rymarkiewicz
2011-03-18 12:19   ` Arnd Bergmann
2011-03-18 12:51     ` Mark Brown
2011-03-18 14:20       ` Arnd Bergmann
2011-03-25 14:26     ` Samuel Ortiz
2011-03-29  8:00       ` Waldemar.Rymarkiewicz
2011-03-29 11:05         ` Arnd Bergmann
2011-03-29 11:59           ` Alan Cox
2011-03-29 12:04             ` Arnd Bergmann
2011-03-29 12:23               ` Alan Cox
2011-03-29 13:22                 ` Arnd Bergmann
2011-03-31 14:16           ` Samuel Ortiz
2011-03-31 14:42             ` Waldemar.Rymarkiewicz
2011-03-31 14:49               ` Arnd Bergmann
2011-03-31 15:09               ` Samuel Ortiz
2011-03-31 15:24                 ` Waldemar.Rymarkiewicz
2011-03-31 15:30                   ` Samuel Ortiz
2011-04-01 18:19                     ` Aloisio Almeida
2011-04-01 19:43                       ` Arnd Bergmann
2011-06-06 20:22                     ` Pavan Savoy
2011-06-06 20:30                       ` Pavan Savoy
2011-06-06 20:46                         ` Aloisio Almeida
2011-06-06 20:50                       ` Samuel Ortiz
2011-03-18 15:50   ` Randy Dunlap
2011-03-18 15:57     ` Waldemar.Rymarkiewicz
  -- strict thread matches above, loose matches on Subject: below --
2011-03-10 14:20 Waldemar Rymarkiewicz
2011-03-10 13:52 ` Arnd Bergmann
2011-03-10 14:45   ` Waldemar.Rymarkiewicz
2011-03-10 16:20     ` Arnd Bergmann
2011-03-14 14:59       ` Waldemar.Rymarkiewicz
2011-03-14 15:34         ` Arnd Bergmann
2011-03-14 15:45           ` Waldemar.Rymarkiewicz
2011-03-14 16:00             ` Arnd Bergmann
2011-03-14 16:15               ` Waldemar.Rymarkiewicz
2011-03-14 17:01                 ` Arnd Bergmann
2011-03-15  8:37                   ` Waldemar.Rymarkiewicz
2011-03-15  9:06                     ` Arnd Bergmann
2011-03-17 12:58       ` Waldemar.Rymarkiewicz
2011-03-17 13:07         ` Arnd Bergmann
2011-03-17 13:38           ` Waldemar.Rymarkiewicz
2011-03-17 13:54             ` Arnd Bergmann
2011-03-17 13:58               ` Waldemar.Rymarkiewicz

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