iwlwifi: support host command with copied data

In addition to the NOCOPY flag, add a DUP flag that
tells the transport to kmemdup() the buffer and free
it after the command completes.

Currently this is only supported for a single buffer
in a given command, but that could be extended if it
should be needed.

Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

5 files changed, 59 insertions, 10 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-trans.h b/drivers/net/wireless/iwlwifi/iwl-trans.h
index f75ea6d73ffc..76c52378f8f7 100644
--- a/drivers/net/wireless/iwlwifi/iwl-trans.h
+++ b/drivers/net/wireless/iwlwifi/iwl-trans.h
@@ -221,14 +221,18 @@ struct iwl_device_cmd {
 /**
  * struct iwl_hcmd_dataflag - flag for each one of the chunks of the command
  *
- * IWL_HCMD_DFL_NOCOPY: By default, the command is copied to the host command's
+ * @IWL_HCMD_DFL_NOCOPY: By default, the command is copied to the host command's
  *      ring. The transport layer doesn't map the command's buffer to DMA, but
  *      rather copies it to an previously allocated DMA buffer. This flag tells
  *      the transport layer not to copy the command, but to map the existing
  *      buffer. This can save memcpy and is worth with very big comamnds.
+ * @IWL_HCMD_DFL_DUP: Only valid without NOCOPY, duplicate the memory for this
+ *      chunk internally and free it again after the command completes. This
+ *      can (currently) be used only once per command.
  */
 enum iwl_hcmd_dataflag {
         IWL_HCMD_DFL_NOCOPY     = BIT(0),
+        IWL_HCMD_DFL_DUP        = BIT(1),
 };
 
 /**
diff --git a/drivers/net/wireless/iwlwifi/pcie/internal.h b/drivers/net/wireless/iwlwifi/pcie/internal.h
index 6ce58f03bc53..ae0f87e0e585 100644
--- a/drivers/net/wireless/iwlwifi/pcie/internal.h
+++ b/drivers/net/wireless/iwlwifi/pcie/internal.h
@@ -186,6 +186,8 @@ struct iwl_pcie_tx_queue_entry {
         struct iwl_device_cmd *cmd;
         struct iwl_device_cmd *copy_cmd;
         struct sk_buff *skb;
+        /* buffer to free after command completes */
+        const void *free_buf;
         struct iwl_cmd_meta meta;
 };
 
diff --git a/drivers/net/wireless/iwlwifi/pcie/rx.c b/drivers/net/wireless/iwlwifi/pcie/rx.c
index 137af4c46a6c..3f03f6e322c3 100644
--- a/drivers/net/wireless/iwlwifi/pcie/rx.c
+++ b/drivers/net/wireless/iwlwifi/pcie/rx.c
@@ -452,6 +452,9 @@ static void iwl_rx_handle_rxbuf(struct iwl_trans *trans,
                         /* The original command isn't needed any more */
                         kfree(txq->entries[cmd_index].copy_cmd);
                         txq->entries[cmd_index].copy_cmd = NULL;
+                        /* nor is the duplicated part of the command */
+                        kfree(txq->entries[cmd_index].free_buf);
+                        txq->entries[cmd_index].free_buf = NULL;
                 }
 
                 /*
diff --git a/drivers/net/wireless/iwlwifi/pcie/trans.c b/drivers/net/wireless/iwlwifi/pcie/trans.c
index a6a518116c7f..b8a155af12cc 100644
--- a/drivers/net/wireless/iwlwifi/pcie/trans.c
+++ b/drivers/net/wireless/iwlwifi/pcie/trans.c
@@ -496,6 +496,7 @@ static void iwl_tx_queue_free(struct iwl_trans *trans, int txq_id)
                 for (i = 0; i < txq->q.n_window; i++) {
                         kfree(txq->entries[i].cmd);
                         kfree(txq->entries[i].copy_cmd);
+                        kfree(txq->entries[i].free_buf);
                 }
 
         /* De-alloc circular buffer of TFDs */
diff --git a/drivers/net/wireless/iwlwifi/pcie/tx.c b/drivers/net/wireless/iwlwifi/pcie/tx.c
index 5db03145186c..9cb30ae5e9a1 100644
--- a/drivers/net/wireless/iwlwifi/pcie/tx.c
+++ b/drivers/net/wireless/iwlwifi/pcie/tx.c
@@ -517,8 +517,9 @@ static int iwl_enqueue_hcmd(struct iwl_trans *trans, struct iwl_host_cmd *cmd)
         struct iwl_queue *q = &txq->q;
         struct iwl_device_cmd *out_cmd;
         struct iwl_cmd_meta *out_meta;
+        void *dup_buf = NULL;
         dma_addr_t phys_addr;
-        u32 idx;
+        int idx;
         u16 copy_size, cmd_size;
         bool had_nocopy = false;
         int i;
@@ -535,10 +536,33 @@ static int iwl_enqueue_hcmd(struct iwl_trans *trans, struct iwl_host_cmd *cmd)
                         continue;
                 if (cmd->dataflags[i] & IWL_HCMD_DFL_NOCOPY) {
                         had_nocopy = true;
+                        if (WARN_ON(cmd->dataflags[i] & IWL_HCMD_DFL_DUP)) {
+                                idx = -EINVAL;
+                                goto free_dup_buf;
+                        }
+                } else if (cmd->dataflags[i] & IWL_HCMD_DFL_DUP) {
+                        /*
+                         * This is also a chunk that isn't copied
+                         * to the static buffer so set had_nocopy.
+                         */
+                        had_nocopy = true;
+
+                        /* only allowed once */
+                        if (WARN_ON(dup_buf)) {
+                                idx = -EINVAL;
+                                goto free_dup_buf;
+                        }
+
+                        dup_buf = kmemdup(cmd->data[i], cmd->len[i],
+                                          GFP_ATOMIC);
+                        if (!dup_buf)
+                                return -ENOMEM;
                 } else {
                         /* NOCOPY must not be followed by normal! */
-                        if (WARN_ON(had_nocopy))
-                                return -EINVAL;
+                        if (WARN_ON(had_nocopy)) {
+                                idx = -EINVAL;
+                                goto free_dup_buf;
+                        }
                         copy_size += cmd->len[i];
                 }
                 cmd_size += cmd->len[i];
@@ -553,8 +577,10 @@ static int iwl_enqueue_hcmd(struct iwl_trans *trans, struct iwl_host_cmd *cmd)
         if (WARN(copy_size > TFD_MAX_PAYLOAD_SIZE,
                  "Command %s (%#x) is too large (%d bytes)\n",
                  trans_pcie_get_cmd_string(trans_pcie, cmd->id),
-                 cmd->id, copy_size))
-                return -EINVAL;
+                 cmd->id, copy_size)) {
+                idx = -EINVAL;
+                goto free_dup_buf;
+        }
 
         spin_lock_bh(&txq->lock);
 
@@ -563,7 +589,8 @@ static int iwl_enqueue_hcmd(struct iwl_trans *trans, struct iwl_host_cmd *cmd)
 
                 IWL_ERR(trans, "No space in command queue\n");
                 iwl_op_mode_cmd_queue_full(trans->op_mode);
-                return -ENOSPC;
+                idx = -ENOSPC;
+                goto free_dup_buf;
         }
 
         idx = get_cmd_index(q, q->write_ptr);
@@ -587,7 +614,8 @@ static int iwl_enqueue_hcmd(struct iwl_trans *trans, struct iwl_host_cmd *cmd)
         for (i = 0; i < IWL_MAX_CMD_TFDS; i++) {
                 if (!cmd->len[i])
                         continue;
-                if (cmd->dataflags[i] & IWL_HCMD_DFL_NOCOPY)
+                if (cmd->dataflags[i] & (IWL_HCMD_DFL_NOCOPY |
+                                         IWL_HCMD_DFL_DUP))
                         break;
                 memcpy((u8 *)out_cmd + cmd_pos, cmd->data[i], cmd->len[i]);
                 cmd_pos += cmd->len[i];
@@ -629,11 +657,16 @@ static int iwl_enqueue_hcmd(struct iwl_trans *trans, struct iwl_host_cmd *cmd)
         iwlagn_txq_attach_buf_to_tfd(trans, txq, phys_addr, copy_size, 1);
 
         for (i = 0; i < IWL_MAX_CMD_TFDS; i++) {
+                const void *data = cmd->data[i];
+
                 if (!cmd->len[i])
                         continue;
-                if (!(cmd->dataflags[i] & IWL_HCMD_DFL_NOCOPY))
+                if (!(cmd->dataflags[i] & (IWL_HCMD_DFL_NOCOPY |
+                                           IWL_HCMD_DFL_DUP)))
                         continue;
-                phys_addr = dma_map_single(trans->dev, (void *)cmd->data[i],
+                if (cmd->dataflags[i] & IWL_HCMD_DFL_DUP)
+                        data = dup_buf;
+                phys_addr = dma_map_single(trans->dev, (void *)data,
                                            cmd->len[i], DMA_BIDIRECTIONAL);
                 if (dma_mapping_error(trans->dev, phys_addr)) {
                         iwl_unmap_tfd(trans, out_meta,
@@ -648,6 +681,9 @@ static int iwl_enqueue_hcmd(struct iwl_trans *trans, struct iwl_host_cmd *cmd)
         }
 
         out_meta->flags = cmd->flags;
+        if (WARN_ON_ONCE(txq->entries[idx].free_buf))
+                kfree(txq->entries[idx].free_buf);
+        txq->entries[idx].free_buf = dup_buf;
 
         txq->need_update = 1;
 
@@ -664,6 +700,9 @@ static int iwl_enqueue_hcmd(struct iwl_trans *trans, struct iwl_host_cmd *cmd)
 
  out:
         spin_unlock_bh(&txq->lock);
+ free_dup_buf:
+        if (idx < 0)
+                kfree(dup_buf);
         return idx;
 }