[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>

1 files changed, 11 insertions, 4 deletions

diff --git a/drivers/char/istallion.c b/drivers/char/istallion.c
index 40c256d787fc..de869241baa0 100644
--- 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);
         }