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>

diff --git a/drivers/net/wireless/iwlwifi/iwl-trans.h b/drivers/net/wireless/iwlwifi/iwl-trans.h
index f75ea6d..76c5237 100644 (file)
--- 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 6ce58f0..ae0f87e 100644 (file)
--- 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 137af4c..3f03f6e 100644 (file)
--- 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 a6a5181..b8a155a 100644 (file)
--- 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 5db0314..9cb30ae 100644 (file)
--- 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;
 }