tile-srom: avoid krealloc(... __GFP_ZERO) pattern

Joe Perches points out [1] that this pattern isn't currently safe.
This driver doesn't really need the zeroing semantic anyway;
by restructuring the code slightly we can initialize all the
fields of the structure up front instead.

[1] https://lkml.kernel.org/r/1469729491.3998.58.camel@perches.com

Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/char/tile-srom.c b/drivers/char/tile-srom.c
index 69f6b4a..398800e 100644 (file)
--- a/drivers/char/tile-srom.c
+++ b/drivers/char/tile-srom.c
@@ -331,13 +331,11 @@ static const struct file_operations srom_fops = {
 /**
  * srom_setup_minor() - Initialize per-minor information.
  * @srom: Per-device SROM state.
- * @index: Device to set up.
+ * @devhdl: Partition device handle.
  */
-static int srom_setup_minor(struct srom_dev *srom, int index)
+static int srom_setup_minor(struct srom_dev *srom, int devhdl)
 {
-       struct device *dev;
-       int devhdl = srom->hv_devhdl;
-
+       srom->hv_devhdl = devhdl;
        mutex_init(&srom->lock);
 
        if (_srom_read(devhdl, &srom->total_size,
@@ -350,9 +348,7 @@ static int srom_setup_minor(struct srom_dev *srom, int index)
                       SROM_PAGE_SIZE_OFF, sizeof(srom->page_size)) < 0)
                return -EIO;
 
-       dev = device_create(srom_class, &srom_parent->dev,
-                           MKDEV(srom_major, index), srom, "%d", index);
-       return PTR_ERR_OR_ZERO(dev);
+       return 0;
 }
 
 /** srom_init() - Initialize the driver's module. */
@@ -365,7 +361,7 @@ static int srom_init(void)
         * Start with a plausible number of partitions; the krealloc() call
         * below will yield about log(srom_devs) additional allocations.
         */
-       srom_devices = kzalloc(4 * sizeof(struct srom_dev), GFP_KERNEL);
+       srom_devices = kmalloc(4 * sizeof(struct srom_dev), GFP_KERNEL);
 
        /* Discover the number of srom partitions. */
        for (i = 0; ; i++) {
@@ -373,7 +369,7 @@ static int srom_init(void)
                char buf[20];
                struct srom_dev *new_srom_devices =
                        krealloc(srom_devices, (i+1) * sizeof(struct srom_dev),
-                                GFP_KERNEL | __GFP_ZERO);
+                                GFP_KERNEL);
                if (!new_srom_devices) {
                        result = -ENOMEM;
                        goto fail_mem;
@@ -387,7 +383,9 @@ static int srom_init(void)
                                          i, devhdl);
                        break;
                }
-               srom_devices[i].hv_devhdl = devhdl;
+               result = srom_setup_minor(&srom_devices[i], devhdl);
+               if (result != 0)
+                       goto fail_mem;
        }
        srom_devs = i;
 
@@ -431,9 +429,13 @@ static int srom_init(void)
        srom_class->dev_groups = srom_dev_groups;
        srom_class->devnode = srom_devnode;
 
-       /* Do per-partition initialization */
+       /* Create per-partition devices */
        for (i = 0; i < srom_devs; i++) {
-               result = srom_setup_minor(srom_devices + i, i);
+               struct device *dev =
+                       device_create(srom_class, &srom_parent->dev,
+                                     MKDEV(srom_major, i), srom_devices + i,
+                                     "%d", i);
+               result = PTR_ERR_OR_ZERO(dev);
                if (result < 0)
                        goto fail_class;
        }