Hello Mark,
On Mon, 29 Nov 2004, Mark M. Hoffman wrote:
> I.e. the way I wrote it was correct but non-optimal? How about this?
> It compiles & runs at least, and it looks correct to me.
Yes, the datum being protected can be accessed atomically without
spinlocks.
> + return xchg(&algo_data->status,0);
> }
>
> static int i801_transaction(struct i2c_adapter *adap, int smbcmd)
> @@ -246,11 +237,8 @@ static irqreturn_t i801_isr(int irq, voi
> if (likely(status & I801_HST_STS_MASK_NORM)) {
> struct i2c_adapter *adap = dev_id;
> struct i2c_i801_algo_data *algo_data = adap->algo_data;
> - unsigned long flags;
>
> - spin_lock_irqsave(&algo_data->lock, flags);
> algo_data->status = status;
> - spin_unlock_irqrestore(&algo_data->lock, flags);
> wake_up_interruptible(&algo_data->waitq);
This needs to be done atomically via xchg too.
Thanks,
Zwane
