param: lock myri10ge_fw_name against sysfs changes.

Since it can be changed via sysfs, we need to make a copy.  This most
generic way of doing this is to keep a flag so we know when to free it.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Cc: Andrew Gallatin <gallatin@myri.com>
Cc: Brice Goglin <brice@myri.com>
Cc: netdev@vger.kernel.org

1 files changed, 41 insertions, 13 deletions

diff --git a/drivers/net/myri10ge/myri10ge.c b/drivers/net/myri10ge/myri10ge.c
index d771d1650d60..fb2c0927d3cc 100644
--- a/drivers/net/myri10ge/myri10ge.c
+++ b/drivers/net/myri10ge/myri10ge.c
@@ -239,6 +239,7 @@ struct myri10ge_priv {
         int watchdog_resets;
         int watchdog_pause;
         int pause;
+        bool fw_name_allocated;
         char *fw_name;
         char eeprom_strings[MYRI10GE_EEPROM_STRINGS_SIZE];
         char *product_code_string;
@@ -271,6 +272,7 @@ MODULE_FIRMWARE("myri10ge_eth_z8e.dat");
 MODULE_FIRMWARE("myri10ge_rss_ethp_z8e.dat");
 MODULE_FIRMWARE("myri10ge_rss_eth_z8e.dat");
 
+/* Careful: must be accessed under kparam_block_sysfs_write */
 static char *myri10ge_fw_name = NULL;
 module_param(myri10ge_fw_name, charp, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(myri10ge_fw_name, "Firmware image name");
@@ -376,6 +378,14 @@ static inline void put_be32(__be32 val, __be32 __iomem * p)
 
 static struct net_device_stats *myri10ge_get_stats(struct net_device *dev);
 
+static void set_fw_name(struct myri10ge_priv *mgp, char *name, bool allocated)
+{
+        if (mgp->fw_name_allocated)
+                kfree(mgp->fw_name);
+        mgp->fw_name = name;
+        mgp->fw_name_allocated = allocated;
+}
+
 static int
 myri10ge_send_cmd(struct myri10ge_priv *mgp, u32 cmd,
                   struct myri10ge_cmd *data, int atomic)
@@ -747,7 +757,7 @@ static int myri10ge_load_firmware(struct myri10ge_priv *mgp, int adopt)
                         dev_warn(&mgp->pdev->dev, "via hotplug\n");
                 }
 
-                mgp->fw_name = "adopted";
+                set_fw_name(mgp, "adopted", false);
                 mgp->tx_boundary = 2048;
                 myri10ge_dummy_rdma(mgp, 1);
                 status = myri10ge_get_firmware_capabilities(mgp);
@@ -3233,7 +3243,7 @@ static void myri10ge_firmware_probe(struct myri10ge_priv *mgp)
          * load the optimized firmware (which assumes aligned PCIe
          * completions) in order to see if it works on this host.
          */
-        mgp->fw_name = myri10ge_fw_aligned;
+        set_fw_name(mgp, myri10ge_fw_aligned, false);
         status = myri10ge_load_firmware(mgp, 1);
         if (status != 0) {
                 goto abort;
@@ -3261,7 +3271,7 @@ static void myri10ge_firmware_probe(struct myri10ge_priv *mgp)
 abort:
         /* fall back to using the unaligned firmware */
         mgp->tx_boundary = 2048;
-        mgp->fw_name = myri10ge_fw_unaligned;
+        set_fw_name(mgp, myri10ge_fw_unaligned, false);
 
 }
 
@@ -3284,7 +3294,7 @@ static void myri10ge_select_firmware(struct myri10ge_priv *mgp)
                         dev_info(&mgp->pdev->dev, "PCIE x%d Link\n",
                                  link_width);
                         mgp->tx_boundary = 4096;
-                        mgp->fw_name = myri10ge_fw_aligned;
+                        set_fw_name(mgp, myri10ge_fw_aligned, false);
                 } else {
                         myri10ge_firmware_probe(mgp);
                 }
@@ -3293,22 +3303,29 @@ static void myri10ge_select_firmware(struct myri10ge_priv *mgp)
                         dev_info(&mgp->pdev->dev,
                                  "Assuming aligned completions (forced)\n");
                         mgp->tx_boundary = 4096;
-                        mgp->fw_name = myri10ge_fw_aligned;
+                        set_fw_name(mgp, myri10ge_fw_aligned, false);
                 } else {
                         dev_info(&mgp->pdev->dev,
                                  "Assuming unaligned completions (forced)\n");
                         mgp->tx_boundary = 2048;
-                        mgp->fw_name = myri10ge_fw_unaligned;
+                        set_fw_name(mgp, myri10ge_fw_unaligned, false);
                 }
         }
+
+        kparam_block_sysfs_write(myri10ge_fw_name);
         if (myri10ge_fw_name != NULL) {
-                overridden = 1;
-                mgp->fw_name = myri10ge_fw_name;
+                char *fw_name = kstrdup(myri10ge_fw_name, GFP_KERNEL);
+                if (fw_name) {
+                        overridden = 1;
+                        set_fw_name(mgp, fw_name, true);
+                }
         }
+        kparam_unblock_sysfs_write(myri10ge_fw_name);
+
         if (mgp->board_number < MYRI10GE_MAX_BOARDS &&
             myri10ge_fw_names[mgp->board_number] != NULL &&
             strlen(myri10ge_fw_names[mgp->board_number])) {
-                mgp->fw_name = myri10ge_fw_names[mgp->board_number];
+                set_fw_name(mgp, myri10ge_fw_names[mgp->board_number], false);
                 overridden = 1;
         }
         if (overridden)
@@ -3660,6 +3677,7 @@ static void myri10ge_probe_slices(struct myri10ge_priv *mgp)
         struct myri10ge_cmd cmd;
         struct pci_dev *pdev = mgp->pdev;
         char *old_fw;
+        bool old_allocated;
         int i, status, ncpus, msix_cap;
 
         mgp->num_slices = 1;
@@ -3672,17 +3690,23 @@ static void myri10ge_probe_slices(struct myri10ge_priv *mgp)
 
         /* try to load the slice aware rss firmware */
         old_fw = mgp->fw_name;
+        old_allocated = mgp->fw_name_allocated;
+        /* don't free old_fw if we override it. */
+        mgp->fw_name_allocated = false;
+
         if (myri10ge_fw_name != NULL) {
                 dev_info(&mgp->pdev->dev, "overriding rss firmware to %s\n",
                          myri10ge_fw_name);
-                mgp->fw_name = myri10ge_fw_name;
+                set_fw_name(mgp, myri10ge_fw_name, false);
         } else if (old_fw == myri10ge_fw_aligned)
-                mgp->fw_name = myri10ge_fw_rss_aligned;
+                set_fw_name(mgp, myri10ge_fw_rss_aligned, false);
         else
-                mgp->fw_name = myri10ge_fw_rss_unaligned;
+                set_fw_name(mgp, myri10ge_fw_rss_unaligned, false);
         status = myri10ge_load_firmware(mgp, 0);
         if (status != 0) {
                 dev_info(&pdev->dev, "Rss firmware not found\n");
+                if (old_allocated)
+                        kfree(old_fw);
                 return;
         }
 
@@ -3747,6 +3771,8 @@ static void myri10ge_probe_slices(struct myri10ge_priv *mgp)
                                          mgp->num_slices);
                 if (status == 0) {
                         pci_disable_msix(pdev);
+                        if (old_allocated)
+                                kfree(old_fw);
                         return;
                 }
                 if (status > 0)
@@ -3763,7 +3789,7 @@ disable_msix:
 
 abort_with_fw:
         mgp->num_slices = 1;
-        mgp->fw_name = old_fw;
+        set_fw_name(mgp, old_fw, old_allocated);
         myri10ge_load_firmware(mgp, 0);
 }
 
@@ -3993,6 +4019,7 @@ abort_with_enabled:
         pci_disable_device(pdev);
 
 abort_with_netdev:
+        set_fw_name(mgp, NULL, false);
         free_netdev(netdev);
         return status;
 }
@@ -4037,6 +4064,7 @@ static void myri10ge_remove(struct pci_dev *pdev)
         dma_free_coherent(&pdev->dev, sizeof(*mgp->cmd),
                           mgp->cmd, mgp->cmd_bus);
 
+        set_fw_name(mgp, NULL, false);
         free_netdev(netdev);
         pci_disable_device(pdev);
         pci_set_drvdata(pdev, NULL);