wifi: iwlwifi: return a new allocation for hdr page space

Instead of returning the pointer to the structure describing the header
page, return the pointer to the newly allocated area. This disentangles
the user from the allocation within the page as it does not need to
advance the position itself.
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Link: https://patch.msgid.link/20240703125541.044f2cb373f1.I52a807ac6f311b89530e18deacc7452638a6f5d8@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/intel/iwlwifi/pcie/internal.h

@@ -623,8 +623,8 @@ void iwl_trans_pcie_tx_reset(struct iwl_trans *trans);
 int iwl_pcie_txq_alloc(struct iwl_trans *trans, struct iwl_txq *txq,
 		       int slots_num, bool cmd_queue);
 
-struct iwl_tso_hdr_page *iwl_pcie_get_page_hdr(struct iwl_trans *trans,
-					       size_t len, struct sk_buff *skb);
+void *iwl_pcie_get_page_hdr(struct iwl_trans *trans, size_t len,
+			    struct sk_buff *skb);
 void iwl_pcie_free_tso_page(struct iwl_trans *trans, struct sk_buff *skb);
 
 static inline dma_addr_t

drivers/net/wireless/intel/iwlwifi/pcie/tx-gen2.c

@@ -130,7 +130,6 @@ static int iwl_txq_gen2_build_amsdu(struct iwl_trans *trans,
 	unsigned int mss = skb_shinfo(skb)->gso_size;
 	u16 length, amsdu_pad;
 	u8 *start_hdr;
-	struct iwl_tso_hdr_page *hdr_page;
 	struct tso_t tso;
 
 	trace_iwlwifi_dev_tx(trans->dev, skb, tfd, sizeof(*tfd),
@@ -146,12 +145,10 @@ static int iwl_txq_gen2_build_amsdu(struct iwl_trans *trans,
 		(3 + snap_ip_tcp_hdrlen + sizeof(struct ethhdr));
 
 	/* Our device supports 9 segments at most, it will fit in 1 page */
-	hdr_page = iwl_pcie_get_page_hdr(trans, hdr_room, skb);
-	if (!hdr_page)
+	start_hdr = iwl_pcie_get_page_hdr(trans, hdr_room, skb);
+	if (!start_hdr)
 		return -ENOMEM;
 
-	start_hdr = hdr_page->pos;
-
 	/*
 	 * Pull the ieee80211 header to be able to use TSO core,
 	 * we will restore it for the tx_status flow.
@@ -172,32 +169,32 @@ static int iwl_txq_gen2_build_amsdu(struct iwl_trans *trans,
 		unsigned int data_left = min_t(unsigned int, mss, total_len);
 		unsigned int tb_len;
 		dma_addr_t tb_phys;
-		u8 *subf_hdrs_start = hdr_page->pos;
+		u8 *pos_hdr = start_hdr;
 
 		total_len -= data_left;
 
-		memset(hdr_page->pos, 0, amsdu_pad);
-		hdr_page->pos += amsdu_pad;
+		memset(pos_hdr, 0, amsdu_pad);
+		pos_hdr += amsdu_pad;
 		amsdu_pad = (4 - (sizeof(struct ethhdr) + snap_ip_tcp_hdrlen +
 				  data_left)) & 0x3;
-		ether_addr_copy(hdr_page->pos, ieee80211_get_DA(hdr));
-		hdr_page->pos += ETH_ALEN;
-		ether_addr_copy(hdr_page->pos, ieee80211_get_SA(hdr));
-		hdr_page->pos += ETH_ALEN;
+		ether_addr_copy(pos_hdr, ieee80211_get_DA(hdr));
+		pos_hdr += ETH_ALEN;
+		ether_addr_copy(pos_hdr, ieee80211_get_SA(hdr));
+		pos_hdr += ETH_ALEN;
 
 		length = snap_ip_tcp_hdrlen + data_left;
-		*((__be16 *)hdr_page->pos) = cpu_to_be16(length);
-		hdr_page->pos += sizeof(length);
+		*((__be16 *)pos_hdr) = cpu_to_be16(length);
+		pos_hdr += sizeof(length);
 
 		/*
 		 * This will copy the SNAP as well which will be considered
 		 * as MAC header.
 		 */
-		tso_build_hdr(skb, hdr_page->pos, &tso, data_left, !total_len);
+		tso_build_hdr(skb, pos_hdr, &tso, data_left, !total_len);
 
-		hdr_page->pos += snap_ip_tcp_hdrlen;
+		pos_hdr += snap_ip_tcp_hdrlen;
 
-		tb_len = hdr_page->pos - start_hdr;
+		tb_len = pos_hdr - start_hdr;
 		tb_phys = dma_map_single(trans->dev, start_hdr,
 					 tb_len, DMA_TO_DEVICE);
 		if (unlikely(dma_mapping_error(trans->dev, tb_phys)))
@@ -211,10 +208,10 @@ static int iwl_txq_gen2_build_amsdu(struct iwl_trans *trans,
 		trace_iwlwifi_dev_tx_tb(trans->dev, skb, start_hdr,
 					tb_phys, tb_len);
 		/* add this subframe's headers' length to the tx_cmd */
-		le16_add_cpu(&tx_cmd->len, hdr_page->pos - subf_hdrs_start);
+		le16_add_cpu(&tx_cmd->len, tb_len);
 
 		/* prepare the start_hdr for the next subframe */
-		start_hdr = hdr_page->pos;
+		start_hdr = pos_hdr;
 
 		/* put the payload */
 		while (data_left) {

drivers/net/wireless/intel/iwlwifi/pcie/tx.c

@@ -1702,12 +1702,13 @@ static int iwl_fill_data_tbs(struct iwl_trans *trans, struct sk_buff *skb,
 }
 
 #ifdef CONFIG_INET
-struct iwl_tso_hdr_page *iwl_pcie_get_page_hdr(struct iwl_trans *trans,
-					       size_t len, struct sk_buff *skb)
+void *iwl_pcie_get_page_hdr(struct iwl_trans *trans,
+			    size_t len, struct sk_buff *skb)
 {
 	struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
 	struct iwl_tso_hdr_page *p = this_cpu_ptr(trans_pcie->txqs.tso_hdr_page);
 	struct page **page_ptr;
+	void *ret;
 
 	page_ptr = (void *)((u8 *)skb->cb + trans_pcie->txqs.page_offs);
 
@@ -1744,7 +1745,10 @@ struct iwl_tso_hdr_page *iwl_pcie_get_page_hdr(struct iwl_trans *trans,
 out:
 	*page_ptr = p->page;
 	get_page(p->page);
-	return p;
+	ret = p->pos;
+	p->pos += len;
+
+	return ret;
 }
 
 static int iwl_fill_data_tbs_amsdu(struct iwl_trans *trans, struct sk_buff *skb,
@@ -1759,8 +1763,7 @@ static int iwl_fill_data_tbs_amsdu(struct iwl_trans *trans, struct sk_buff *skb,
 	unsigned int snap_ip_tcp_hdrlen, ip_hdrlen, total_len, hdr_room;
 	unsigned int mss = skb_shinfo(skb)->gso_size;
 	u16 length, iv_len, amsdu_pad;
-	u8 *start_hdr;
-	struct iwl_tso_hdr_page *hdr_page;
+	u8 *start_hdr, *pos_hdr;
 	struct tso_t tso;
 
 	/* if the packet is protected, then it must be CCMP or GCMP */
@@ -1783,13 +1786,12 @@ static int iwl_fill_data_tbs_amsdu(struct iwl_trans *trans, struct sk_buff *skb,
 		(3 + snap_ip_tcp_hdrlen + sizeof(struct ethhdr)) + iv_len;
 
 	/* Our device supports 9 segments at most, it will fit in 1 page */
-	hdr_page = iwl_pcie_get_page_hdr(trans, hdr_room, skb);
-	if (!hdr_page)
+	pos_hdr = start_hdr = iwl_pcie_get_page_hdr(trans, hdr_room, skb);
+	if (!start_hdr)
 		return -ENOMEM;
 
-	start_hdr = hdr_page->pos;
-	memcpy(hdr_page->pos, skb->data + hdr_len, iv_len);
-	hdr_page->pos += iv_len;
+	memcpy(pos_hdr, skb->data + hdr_len, iv_len);
+	pos_hdr += iv_len;
 
 	/*
 	 * Pull the ieee80211 header + IV to be able to use TSO core,
@@ -1812,32 +1814,32 @@ static int iwl_fill_data_tbs_amsdu(struct iwl_trans *trans, struct sk_buff *skb,
 			min_t(unsigned int, mss, total_len);
 		unsigned int hdr_tb_len;
 		dma_addr_t hdr_tb_phys;
-		u8 *subf_hdrs_start = hdr_page->pos;
+		u8 *subf_hdrs_start = pos_hdr;
 
 		total_len -= data_left;
 
-		memset(hdr_page->pos, 0, amsdu_pad);
-		hdr_page->pos += amsdu_pad;
+		memset(pos_hdr, 0, amsdu_pad);
+		pos_hdr += amsdu_pad;
 		amsdu_pad = (4 - (sizeof(struct ethhdr) + snap_ip_tcp_hdrlen +
 				  data_left)) & 0x3;
-		ether_addr_copy(hdr_page->pos, ieee80211_get_DA(hdr));
-		hdr_page->pos += ETH_ALEN;
-		ether_addr_copy(hdr_page->pos, ieee80211_get_SA(hdr));
-		hdr_page->pos += ETH_ALEN;
+		ether_addr_copy(pos_hdr, ieee80211_get_DA(hdr));
+		pos_hdr += ETH_ALEN;
+		ether_addr_copy(pos_hdr, ieee80211_get_SA(hdr));
+		pos_hdr += ETH_ALEN;
 
 		length = snap_ip_tcp_hdrlen + data_left;
-		*((__be16 *)hdr_page->pos) = cpu_to_be16(length);
-		hdr_page->pos += sizeof(length);
+		*((__be16 *)pos_hdr) = cpu_to_be16(length);
+		pos_hdr += sizeof(length);
 
 		/*
 		 * This will copy the SNAP as well which will be considered
 		 * as MAC header.
 		 */
-		tso_build_hdr(skb, hdr_page->pos, &tso, data_left, !total_len);
+		tso_build_hdr(skb, pos_hdr, &tso, data_left, !total_len);
 
-		hdr_page->pos += snap_ip_tcp_hdrlen;
+		pos_hdr += snap_ip_tcp_hdrlen;
 
-		hdr_tb_len = hdr_page->pos - start_hdr;
+		hdr_tb_len = pos_hdr - start_hdr;
 		hdr_tb_phys = dma_map_single(trans->dev, start_hdr,
 					     hdr_tb_len, DMA_TO_DEVICE);
 		if (unlikely(dma_mapping_error(trans->dev, hdr_tb_phys)))
@@ -1847,10 +1849,10 @@ static int iwl_fill_data_tbs_amsdu(struct iwl_trans *trans, struct sk_buff *skb,
 		trace_iwlwifi_dev_tx_tb(trans->dev, skb, start_hdr,
 					hdr_tb_phys, hdr_tb_len);
 		/* add this subframe's headers' length to the tx_cmd */
-		le16_add_cpu(&tx_cmd->len, hdr_page->pos - subf_hdrs_start);
+		le16_add_cpu(&tx_cmd->len, pos_hdr - subf_hdrs_start);
 
 		/* prepare the start_hdr for the next subframe */
-		start_hdr = hdr_page->pos;
+		start_hdr = pos_hdr;
 
 		/* put the payload */
 		while (data_left) {