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>

1 files changed, 27 insertions, 14 deletions

diff --git a/drivers/firewire/fw-device.c b/drivers/firewire/fw-device.c
index 870125a3638e..20ac9a5afc37 100644
--- 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)