drivercore: revert addition of of_match to struct device

Commit b826291c, "drivercore/dt: add a match table pointer to struct
device" added an of_match pointer to struct device to cache the
of_match_table entry discovered at driver match time.  This was unsafe
because matching is not an atomic operation with probing a driver.  If
two or more drivers are attempted to be matched to a driver at the
same time, then the cached matching entry pointer could get
overwritten.

This patch reverts the of_match cache pointer and reworks all users to
call of_match_device() directly instead.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

3 files changed, 19 insertions, 9 deletions

diff --git a/drivers/char/hw_random/n2-drv.c b/drivers/char/hw_random/n2-drv.c
index 43ac61978d8b..ac6739e085e3 100644
--- a/drivers/char/hw_random/n2-drv.c
+++ b/drivers/char/hw_random/n2-drv.c
@@ -619,15 +619,18 @@ static void __devinit n2rng_driver_version(void)
                 pr_info("%s", version);
 }
 
+static const struct of_device_id n2rng_match[];
 static int __devinit n2rng_probe(struct platform_device *op)
 {
+        const struct of_device_id *match;
         int victoria_falls;
         int err = -ENOMEM;
         struct n2rng *np;
 
-        if (!op->dev.of_match)
+        match = of_match_device(n2rng_match, &op->dev);
+        if (!match)
                 return -EINVAL;
-        victoria_falls = (op->dev.of_match->data != NULL);
+        victoria_falls = (match->data != NULL);
 
         n2rng_driver_version();
         np = kzalloc(sizeof(*np), GFP_KERNEL);
diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
index cc6c9b2546a3..64c6b8530615 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -2554,9 +2554,11 @@ static struct pci_driver ipmi_pci_driver = {
 };
 #endif /* CONFIG_PCI */
 
+static struct of_device_id ipmi_match[];
 static int __devinit ipmi_probe(struct platform_device *dev)
 {
 #ifdef CONFIG_OF
+        const struct of_device_id *match;
         struct smi_info *info;
         struct resource resource;
         const __be32 *regsize, *regspacing, *regshift;
@@ -2566,7 +2568,8 @@ static int __devinit ipmi_probe(struct platform_device *dev)
 
         dev_info(&dev->dev, "probing via device tree\n");
 
-        if (!dev->dev.of_match)
+        match = of_match_device(ipmi_match, &dev->dev);
+        if (!match)
                 return -EINVAL;
 
         ret = of_address_to_resource(np, 0, &resource);
@@ -2601,7 +2604,7 @@ static int __devinit ipmi_probe(struct platform_device *dev)
                 return -ENOMEM;
         }
 
-        info->si_type           = (enum si_type) dev->dev.of_match->data;
+        info->si_type           = (enum si_type) match->data;
         info->addr_source       = SI_DEVICETREE;
         info->irq_setup         = std_irq_setup;
 
diff --git a/drivers/char/xilinx_hwicap/xilinx_hwicap.c b/drivers/char/xilinx_hwicap/xilinx_hwicap.c
index d6412c16385f..39ccdeada791 100644
--- a/drivers/char/xilinx_hwicap/xilinx_hwicap.c
+++ b/drivers/char/xilinx_hwicap/xilinx_hwicap.c
@@ -715,13 +715,13 @@ static int __devexit hwicap_remove(struct device *dev)
 }
 
 #ifdef CONFIG_OF
-static int __devinit hwicap_of_probe(struct platform_device *op)
+static int __devinit hwicap_of_probe(struct platform_device *op,
+                                     const struct hwicap_driver_config *config)
 {
         struct resource res;
         const unsigned int *id;
         const char *family;
         int rc;
-        const struct hwicap_driver_config *config = op->dev.of_match->data;
         const struct config_registers *regs;
 
 
@@ -751,20 +751,24 @@ static int __devinit hwicap_of_probe(struct platform_device *op)
                         regs);
 }
 #else
-static inline int hwicap_of_probe(struct platform_device *op)
+static inline int hwicap_of_probe(struct platform_device *op,
+                                  const struct hwicap_driver_config *config)
 {
         return -EINVAL;
 }
 #endif /* CONFIG_OF */
 
+static const struct of_device_id __devinitconst hwicap_of_match[];
 static int __devinit hwicap_drv_probe(struct platform_device *pdev)
 {
+        const struct of_device_id *match;
         struct resource *res;
         const struct config_registers *regs;
         const char *family;
 
-        if (pdev->dev.of_match)
-                return hwicap_of_probe(pdev);
+        match = of_match_device(hwicap_of_match, &pdev->dev);
+        if (match)
+                return hwicap_of_probe(pdev, match->data);
 
         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
         if (!res)