From df67a1bea0378488a0454f2be2609349fda86727 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Fri, 17 Apr 2020 13:21:38 +0300 Subject: [PATCH] iwlwifi: pcie: use seq_file for tx_queue debugfs file On newer hardware, the tx_queue debugfs file would need to allocate 37.5kib data since there are 512 queues, which is too much. Rather than resorting to kludges like kvmalloc(), use the seq_file API to print out the data. While at it, also fix a NULL pointer dereference here, the txq pointer from trans_pcie->txqs[] may be NULL if that queue hasn't been allocated. Signed-off-by: Johannes Berg Signed-off-by: Luca Coelho Link: https://lore.kernel.org/r/iwlwifi.20200417131727.491cf8224c49.I7f154d81e5becef3b5ff22d7c6e36170bde0d7d5@changeid --- drivers/net/wireless/intel/iwlwifi/pcie/trans.c | 121 +++++++++++++++++------- 1 file changed, 89 insertions(+), 32 deletions(-) diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c index e4cbd8d..3c33c01 100644 --- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c +++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c @@ -70,6 +70,7 @@ #include #include #include +#include #include "iwl-drv.h" #include "iwl-trans.h" @@ -2544,44 +2545,94 @@ static const struct file_operations iwl_dbgfs_##name##_ops = { \ .llseek = generic_file_llseek, \ }; -static ssize_t iwl_dbgfs_tx_queue_read(struct file *file, - char __user *user_buf, - size_t count, loff_t *ppos) +struct iwl_dbgfs_tx_queue_priv { + struct iwl_trans *trans; +}; + +struct iwl_dbgfs_tx_queue_state { + loff_t pos; +}; + +static void *iwl_dbgfs_tx_queue_seq_start(struct seq_file *seq, loff_t *pos) { - struct iwl_trans *trans = file->private_data; + struct iwl_dbgfs_tx_queue_priv *priv = seq->private; + struct iwl_dbgfs_tx_queue_state *state; + + if (*pos >= priv->trans->trans_cfg->base_params->num_of_queues) + return NULL; + + state = kmalloc(sizeof(*state), GFP_KERNEL); + if (!state) + return NULL; + state->pos = *pos; + return state; +} + +static void *iwl_dbgfs_tx_queue_seq_next(struct seq_file *seq, + void *v, loff_t *pos) +{ + struct iwl_dbgfs_tx_queue_priv *priv = seq->private; + struct iwl_dbgfs_tx_queue_state *state = v; + + *pos = ++state->pos; + + if (*pos >= priv->trans->trans_cfg->base_params->num_of_queues) + return NULL; + + return state; +} + +static void iwl_dbgfs_tx_queue_seq_stop(struct seq_file *seq, void *v) +{ + kfree(v); +} + +static int iwl_dbgfs_tx_queue_seq_show(struct seq_file *seq, void *v) +{ + struct iwl_dbgfs_tx_queue_priv *priv = seq->private; + struct iwl_dbgfs_tx_queue_state *state = v; + struct iwl_trans *trans = priv->trans; struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans); - struct iwl_txq *txq; - char *buf; - int pos = 0; - int cnt; - int ret; - size_t bufsz; + struct iwl_txq *txq = trans_pcie->txq[state->pos]; + + seq_printf(seq, "hwq %.3u: used=%d stopped=%d ", + (unsigned int)state->pos, + !!test_bit(state->pos, trans_pcie->queue_used), + !!test_bit(state->pos, trans_pcie->queue_stopped)); + if (txq) + seq_printf(seq, + "read=%u write=%u need_update=%d frozen=%d", + txq->read_ptr, txq->write_ptr, + txq->need_update, txq->frozen); + else + seq_puts(seq, "(unallocated)"); - bufsz = sizeof(char) * 75 * - trans->trans_cfg->base_params->num_of_queues; + if (state->pos == trans_pcie->cmd_queue) + seq_puts(seq, " (HCMD)"); + seq_puts(seq, "\n"); - if (!trans_pcie->txq_memory) - return -EAGAIN; + return 0; +} - buf = kzalloc(bufsz, GFP_KERNEL); - if (!buf) +static const struct seq_operations iwl_dbgfs_tx_queue_seq_ops = { + .start = iwl_dbgfs_tx_queue_seq_start, + .next = iwl_dbgfs_tx_queue_seq_next, + .stop = iwl_dbgfs_tx_queue_seq_stop, + .show = iwl_dbgfs_tx_queue_seq_show, +}; + +static int iwl_dbgfs_tx_queue_open(struct inode *inode, struct file *filp) +{ + struct iwl_dbgfs_tx_queue_priv *priv; + + priv = __seq_open_private(filp, &iwl_dbgfs_tx_queue_seq_ops, + sizeof(*priv)); + + if (!priv) return -ENOMEM; - for (cnt = 0; - cnt < trans->trans_cfg->base_params->num_of_queues; - cnt++) { - txq = trans_pcie->txq[cnt]; - pos += scnprintf(buf + pos, bufsz - pos, - "hwq %.2d: read=%u write=%u use=%d stop=%d need_update=%d frozen=%d%s\n", - cnt, txq->read_ptr, txq->write_ptr, - !!test_bit(cnt, trans_pcie->queue_used), - !!test_bit(cnt, trans_pcie->queue_stopped), - txq->need_update, txq->frozen, - (cnt == trans_pcie->cmd_queue ? " HCMD" : "")); - } - ret = simple_read_from_buffer(user_buf, count, ppos, buf, pos); - kfree(buf); - return ret; + priv->trans = inode->i_private; + return 0; } static ssize_t iwl_dbgfs_rx_queue_read(struct file *file, @@ -2914,9 +2965,15 @@ static ssize_t iwl_dbgfs_monitor_data_read(struct file *file, DEBUGFS_READ_WRITE_FILE_OPS(interrupt); DEBUGFS_READ_FILE_OPS(fh_reg); DEBUGFS_READ_FILE_OPS(rx_queue); -DEBUGFS_READ_FILE_OPS(tx_queue); DEBUGFS_WRITE_FILE_OPS(csr); DEBUGFS_READ_WRITE_FILE_OPS(rfkill); +static const struct file_operations iwl_dbgfs_tx_queue_ops = { + .owner = THIS_MODULE, + .open = iwl_dbgfs_tx_queue_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release_private, +}; static const struct file_operations iwl_dbgfs_monitor_data_ops = { .read = iwl_dbgfs_monitor_data_read, -- 2.7.4