firewire: replace static ROM cache by allocated cache

read_bus_info_block() is repeatedly called by workqueue jobs.
These will step on each others toes eventually if there are multiple
workqueue threads, and we end up with corrupt config ROM images.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

diff --git a/drivers/firewire/fw-device.c b/drivers/firewire/fw-device.c
index 870125a..20ac9a5 100644 (file)
--- a/drivers/firewire/fw-device.c
+++ b/drivers/firewire/fw-device.c
@@ -400,6 +400,9 @@ read_rom(struct fw_device *device, int generation, int index, u32 *data)
        return callback_data.rcode;
 }
 
+#define READ_BIB_ROM_SIZE      256
+#define READ_BIB_STACK_SIZE    16
+
 /*
  * Read the bus info block, perform a speed probe, and read all of the rest of
  * the config ROM.  We do all this with a cached bus generation.  If the bus
@@ -409,16 +412,23 @@ read_rom(struct fw_device *device, int generation, int index, u32 *data)
  */
 static int read_bus_info_block(struct fw_device *device, int generation)
 {
-       static u32 rom[256];
-       u32 stack[16], sp, key;
-       int i, end, length;
+       u32 *rom, *stack;
+       u32 sp, key;
+       int i, end, length, ret = -1;
+
+       rom = kmalloc(sizeof(*rom) * READ_BIB_ROM_SIZE +
+                     sizeof(*stack) * READ_BIB_STACK_SIZE, GFP_KERNEL);
+       if (rom == NULL)
+               return -ENOMEM;
+
+       stack = &rom[READ_BIB_ROM_SIZE];
 
        device->max_speed = SCODE_100;
 
        /* First read the bus info block. */
        for (i = 0; i < 5; i++) {
                if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
-                       return -1;
+                       goto out;
                /*
                 * As per IEEE1212 7.2, during power-up, devices can
                 * reply with a 0 for the first quadlet of the config
@@ -428,7 +438,7 @@ static int read_bus_info_block(struct fw_device *device, int generation)
                 * retry mechanism will try again later.
                 */
                if (i == 0 && rom[i] == 0)
-                       return -1;
+                       goto out;
        }
 
        device->max_speed = device->node->max_speed;
@@ -478,26 +488,26 @@ static int read_bus_info_block(struct fw_device *device, int generation)
                 */
                key = stack[--sp];
                i = key & 0xffffff;
-               if (i >= ARRAY_SIZE(rom))
+               if (i >= READ_BIB_ROM_SIZE)
                        /*
                         * The reference points outside the standard
                         * config rom area, something's fishy.
                         */
-                       return -1;
+                       goto out;
 
                /* Read header quadlet for the block to get the length. */
                if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
-                       return -1;
+                       goto out;
                end = i + (rom[i] >> 16) + 1;
                i++;
-               if (end > ARRAY_SIZE(rom))
+               if (end > READ_BIB_ROM_SIZE)
                        /*
                         * This block extends outside standard config
                         * area (and the array we're reading it
                         * into).  That's broken, so ignore this
                         * device.
                         */
-                       return -1;
+                       goto out;
 
                /*
                 * Now read in the block.  If this is a directory
@@ -507,9 +517,9 @@ static int read_bus_info_block(struct fw_device *device, int generation)
                while (i < end) {
                        if (read_rom(device, generation, i, &rom[i]) !=
                            RCODE_COMPLETE)
-                               return -1;
+                               goto out;
                        if ((key >> 30) == 3 && (rom[i] >> 30) > 1 &&
-                           sp < ARRAY_SIZE(stack))
+                           sp < READ_BIB_STACK_SIZE)
                                stack[sp++] = i + rom[i];
                        i++;
                }
@@ -519,11 +529,14 @@ static int read_bus_info_block(struct fw_device *device, int generation)
 
        device->config_rom = kmalloc(length * 4, GFP_KERNEL);
        if (device->config_rom == NULL)
-               return -1;
+               goto out;
        memcpy(device->config_rom, rom, length * 4);
        device->config_rom_length = length;
+       ret = 0;
+ out:
+       kfree(rom);
 
-       return 0;
+       return ret;
 }
 
 static void fw_unit_release(struct device *dev)