Messages in this thread | | | Date | Fri, 18 May 2007 23:25:52 +0200 | From | "Jiri Slaby" <> | Subject | Re: [PATCH 1/1] Misc: phantom, move to unlocked_ioctl |
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On 5/18/07, Andrew Morton <akpm@linux-foundation.org> wrote: > On Fri, 18 May 2007 22:34:53 +0200 (CEST) > Jiri Slaby <jirislaby@gmail.com> wrote: > > > @@ -118,7 +125,9 @@ static int phantom_ioctl(struct inode *inode, struct file *file, u_int cmd, > > if (r.reg > 7) > > return -EINVAL; > > > > + spin_lock(&dev->ioctl_lock); > > r.value = ioread32(dev->iaddr + r.reg); > > + spin_unlock(&dev->ioctl_lock); > > What is that locking protecting in here?
Well, what led me to do it is that I didn't know how much atomic are ioread and iowrite. If concurrent process writes something to the place in that space while the other one is reading it, doesn't matter, correct?
thanks, -- http://www.fi.muni.cz/~xslaby/ Jiri Slaby faculty of informatics, masaryk university, brno, cz e-mail: jirislaby gmail com, gpg pubkey fingerprint: B674 9967 0407 CE62 ACC8 22A0 32CC 55C3 39D4 7A7E - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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