iwlwifi: fix flow handler debug code

iwl_dbgfs_fh_reg_read() can cause crashes and/or
BUG_ON in slub because the ifdefs are wrong, the
code in iwl_dump_fh() should use DEBUGFS, not
DEBUG to protect the buffer writing code.

Also, while at it, clean up the arguments to the
function, some code and make it generally safer.

Cc: stable@vger.kernel.org
Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/iwlwifi/pcie/internal.h b/drivers/net/wireless/iwlwifi/pcie/internal.h
index d9694c5..4ffc18d 100644 (file)
--- a/drivers/net/wireless/iwlwifi/pcie/internal.h
+++ b/drivers/net/wireless/iwlwifi/pcie/internal.h
@@ -350,7 +350,7 @@ int iwl_queue_space(const struct iwl_queue *q);
 /*****************************************************
 * Error handling
 ******************************************************/
-int iwl_dump_fh(struct iwl_trans *trans, char **buf, bool display);
+int iwl_dump_fh(struct iwl_trans *trans, char **buf);
 void iwl_dump_csr(struct iwl_trans *trans);
 
 /*****************************************************

diff --git a/drivers/net/wireless/iwlwifi/pcie/rx.c b/drivers/net/wireless/iwlwifi/pcie/rx.c
index 39a6ca1..d1a61ba 100644 (file)
--- a/drivers/net/wireless/iwlwifi/pcie/rx.c
+++ b/drivers/net/wireless/iwlwifi/pcie/rx.c
@@ -555,7 +555,7 @@ static void iwl_irq_handle_error(struct iwl_trans *trans)
        }
 
        iwl_dump_csr(trans);
-       iwl_dump_fh(trans, NULL, false);
+       iwl_dump_fh(trans, NULL);
 
        iwl_op_mode_nic_error(trans->op_mode);
 }

diff --git a/drivers/net/wireless/iwlwifi/pcie/trans.c b/drivers/net/wireless/iwlwifi/pcie/trans.c
index 939c2f7..1e86ea2 100644 (file)
--- a/drivers/net/wireless/iwlwifi/pcie/trans.c
+++ b/drivers/net/wireless/iwlwifi/pcie/trans.c
@@ -1649,13 +1649,9 @@ static const char *get_fh_string(int cmd)
 #undef IWL_CMD
 }
 
-int iwl_dump_fh(struct iwl_trans *trans, char **buf, bool display)
+int iwl_dump_fh(struct iwl_trans *trans, char **buf)
 {
        int i;
-#ifdef CONFIG_IWLWIFI_DEBUG
-       int pos = 0;
-       size_t bufsz = 0;
-#endif
        static const u32 fh_tbl[] = {
                FH_RSCSR_CHNL0_STTS_WPTR_REG,
                FH_RSCSR_CHNL0_RBDCB_BASE_REG,
@@ -1667,29 +1663,35 @@ int iwl_dump_fh(struct iwl_trans *trans, char **buf, bool display)
                FH_TSSR_TX_STATUS_REG,
                FH_TSSR_TX_ERROR_REG
        };
-#ifdef CONFIG_IWLWIFI_DEBUG
-       if (display) {
-               bufsz = ARRAY_SIZE(fh_tbl) * 48 + 40;
+
+#ifdef CONFIG_IWLWIFI_DEBUGFS
+       if (buf) {
+               int pos = 0;
+               size_t bufsz = ARRAY_SIZE(fh_tbl) * 48 + 40;
+
                *buf = kmalloc(bufsz, GFP_KERNEL);
                if (!*buf)
                        return -ENOMEM;
+
                pos += scnprintf(*buf + pos, bufsz - pos,
                                "FH register values:\n");
-               for (i = 0; i < ARRAY_SIZE(fh_tbl); i++) {
+
+               for (i = 0; i < ARRAY_SIZE(fh_tbl); i++)
                        pos += scnprintf(*buf + pos, bufsz - pos,
                                "  %34s: 0X%08x\n",
                                get_fh_string(fh_tbl[i]),
                                iwl_read_direct32(trans, fh_tbl[i]));
-               }
+
                return pos;
        }
 #endif
+
        IWL_ERR(trans, "FH register values:\n");
-       for (i = 0; i <  ARRAY_SIZE(fh_tbl); i++) {
+       for (i = 0; i <  ARRAY_SIZE(fh_tbl); i++)
                IWL_ERR(trans, "  %34s: 0X%08x\n",
                        get_fh_string(fh_tbl[i]),
                        iwl_read_direct32(trans, fh_tbl[i]));
-       }
+
        return 0;
 }
 
@@ -1982,11 +1984,11 @@ static ssize_t iwl_dbgfs_fh_reg_read(struct file *file,
                                     size_t count, loff_t *ppos)
 {
        struct iwl_trans *trans = file->private_data;
-       char *buf;
+       char *buf = NULL;
        int pos = 0;
        ssize_t ret = -EFAULT;
 
-       ret = pos = iwl_dump_fh(trans, &buf, true);
+       ret = pos = iwl_dump_fh(trans, &buf);
        if (buf) {
                ret = simple_read_from_buffer(user_buf,
                                              count, ppos, buf, pos);