[PATCH] Char: stallion, brd struct locking

Since assigning of stl_brds[brdnr] is racy, add locking to this critical
section.

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, 13 insertions, 5 deletions

diff --git a/drivers/char/stallion.c b/drivers/char/stallion.c
index 7612464beeb1..87bda40be61a 100644
--- a/drivers/char/stallion.c
+++ b/drivers/char/stallion.c
@@ -136,6 +136,7 @@ static char		stl_unwanted[SC26198_RXFIFOSIZE];
 
 /*****************************************************************************/
 
+static DEFINE_MUTEX(stl_brdslock);
 static struct stlbrd            *stl_brds[STL_MAXBRDS];
 
 /*
@@ -2303,7 +2304,6 @@ static int __devinit stl_brdinit(struct stlbrd *brdp)
                 goto err;
         }
 
-        stl_brds[brdp->brdnr] = brdp;
         if ((brdp->state & BRD_FOUND) == 0) {
                 printk("STALLION: %s board not found, board=%d io=%x irq=%d\n",
                         stl_brdnames[brdp->brdtype], brdp->brdnr,
@@ -2329,8 +2329,6 @@ err_free:
         release_region(brdp->ioaddr1, brdp->iosize1);
         if (brdp->iosize2 > 0)
                 release_region(brdp->ioaddr2, brdp->iosize2);
-
-        stl_brds[brdp->brdnr] = NULL;
 err:
         return retval;
 }
@@ -2383,12 +2381,17 @@ static int __devinit stl_pciprobe(struct pci_dev *pdev,
                 retval = -ENOMEM;
                 goto err;
         }
+        mutex_lock(&stl_brdslock);
         brdp->brdnr = stl_getbrdnr();
         if (brdp->brdnr < 0) {
                 dev_err(&pdev->dev, "too many boards found, "
                         "maximum supported %d\n", STL_MAXBRDS);
+                mutex_unlock(&stl_brdslock);
                 goto err_fr;
         }
+        stl_brds[brdp->brdnr] = brdp;
+        mutex_unlock(&stl_brdslock);
+
         brdp->brdtype = brdtype;
         brdp->state |= STL_PROBED;
 
@@ -2417,11 +2420,13 @@ static int __devinit stl_pciprobe(struct pci_dev *pdev,
         brdp->irq = pdev->irq;
         retval = stl_brdinit(brdp);
         if (retval)
-                goto err_fr;
+                goto err_null;
 
         pci_set_drvdata(pdev, brdp);
 
         return 0;
+err_null:
+        stl_brds[brdp->brdnr] = NULL;
 err_fr:
         kfree(brdp);
 err:
@@ -4735,10 +4740,13 @@ static int __init stallion_module_init(void)
                 brdp->irqtype = conf.irqtype;
                 if (stl_brdinit(brdp))
                         kfree(brdp);
-                else
+                else {
+                        stl_brds[brdp->brdnr] = brdp;
                         stl_nrbrds = i + 1;
+                }
         }
 
+        /* this has to be _after_ isa finding because of locking */
         retval = pci_register_driver(&stl_pcidriver);
         if (retval && stl_nrbrds == 0)
                 goto err;