Date: Wed, 2 Oct 2002 11:16:26 +0100
From: Russell King <rmk@arm.linux.org.uk>
To: linux-kernel@vger.kernel.org
Subject: Dereferencing semaphores and atomic_t's
Message-ID: <20021002111625.B24770@flint.arm.linux.org.uk>
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drivers/scsi/scsi_error.c:

        SCSI_LOG_ERROR_RECOVERY(3, printk("Wake up parent %d\n",
                                          shost->eh_notify->count.counter));

        up(shost->eh_notify);

drivers/scsi/hosts.c:

                up(shost->eh_wait);
                SCSI_LOG_ERROR_RECOVERY(5, printk("Waking error handler"
                                          "thread (%d)\n",
                                          atomic_read(&shost->eh_wait->count)));


                up(shost->eh_wait);
                SCSI_LOG_ERROR_RECOVERY(5, printk("Waking error handler"
                                          "thread (%d)\n",
                                          atomic_read(&shost->eh_wait->count)));

Do we really allow this type of layering violation?

(There appear to be some circumstances when obtaining the semaphore count is
useful, but shouldn't we provide an architecture helper function to do that
since a semaphore structure _is_ an architecture-defined opaque structure.)

-- 
Russell King (rmk@arm.linux.org.uk)                The developer of ARM Linux
             http://www.arm.linux.org.uk/personal/aboutme.html

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