[PATCH] Char: istallion, brdnr locking

Kill possible race when getting brdnr by locking.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/char/istallion.c b/drivers/char/istallion.c
index 40c256d787fc8e27a1bef0adab13385b34eb4029..de869241baa040bef7bf18c084f0c40bd8eb6190 100644 (file)
--- a/drivers/char/istallion.c
+++ b/drivers/char/istallion.c
@@ -189,6 +189,7 @@ static struct asystats      stli_cdkstats;
 
 /*****************************************************************************/
 
+static DEFINE_MUTEX(stli_brdslock);
 static struct stlibrd  *stli_brds[STL_MAXBRDS];
 
 static int             stli_shared;
@@ -3677,8 +3678,6 @@ stli_donestartup:
 
 static int __devinit stli_brdinit(struct stlibrd *brdp)
 {
-       stli_brds[brdp->brdnr] = brdp;
-
        switch (brdp->brdtype) {
        case BRD_ECP:
        case BRD_ECPE:
@@ -3896,6 +3895,7 @@ static int stli_findeisabrds(void)
                outb(0x1, (iobase + 0xc84));
                if (stli_eisamemprobe(brdp))
                        outb(0, (iobase + 0xc84));
+               stli_brds[brdp->brdnr] = brdp;
                stli_brdinit(brdp);
        }
 
@@ -3933,14 +3933,18 @@ static int __devinit stli_pciprobe(struct pci_dev *pdev,
                retval = -ENOMEM;
                goto err;
        }
+       mutex_lock(&stli_brdslock);
        brdnr = stli_getbrdnr();
-       if (brdnr < 0) { /* TODO: locking */
+       if (brdnr < 0) {
                printk(KERN_INFO "STALLION: too many boards found, "
                        "maximum supported %d\n", STL_MAXBRDS);
+               mutex_unlock(&stli_brdslock);
                retval = -EIO;
                goto err_fr;
        }
        brdp->brdnr = (unsigned int)brdnr;
+       stli_brds[brdp->brdnr] = brdp;
+       mutex_unlock(&stli_brdslock);
        brdp->brdtype = BRD_ECPPCI;
 /*
  *     We have all resources from the board, so lets setup the actual
@@ -3950,11 +3954,13 @@ static int __devinit stli_pciprobe(struct pci_dev *pdev,
        brdp->memaddr = pci_resource_start(pdev, 2);
        retval = stli_brdinit(brdp);
        if (retval)
-               goto err_fr;
+               goto err_null;
 
        pci_set_drvdata(pdev, brdp);
 
        return 0;
+err_null:
+       stli_brds[brdp->brdnr] = NULL;
 err_fr:
        kfree(brdp);
 err:
@@ -4026,6 +4032,7 @@ static int stli_initbrds(void)
                brdp->brdtype = conf.brdtype;
                brdp->iobase = conf.ioaddr1;
                brdp->memaddr = conf.memaddr;
+               stli_brds[brdp->brdnr] = brdp;
                stli_brdinit(brdp);
        }