mlx5: Remove checksum on command interface commands

Checksum calculations consume CPU resources and can be significant to
the rate of resource creation/destruction.

Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/net/ethernet/mellanox/mlx5/core/cmd.c

@@ -180,28 +180,32 @@ static int verify_block_sig(struct mlx5_cmd_prot_block *block)
 	return 0;
 }
 
-static void calc_block_sig(struct mlx5_cmd_prot_block *block, u8 token)
+static void calc_block_sig(struct mlx5_cmd_prot_block *block, u8 token,
+			   int csum)
 {
 	block->token = token;
-	block->ctrl_sig = ~xor8_buf(block->rsvd0, sizeof(*block) - sizeof(block->data) - 2);
-	block->sig = ~xor8_buf(block, sizeof(*block) - 1);
+	if (csum) {
+		block->ctrl_sig = ~xor8_buf(block->rsvd0, sizeof(*block) -
+					    sizeof(block->data) - 2);
+		block->sig = ~xor8_buf(block, sizeof(*block) - 1);
+	}
 }
 
-static void calc_chain_sig(struct mlx5_cmd_msg *msg, u8 token)
+static void calc_chain_sig(struct mlx5_cmd_msg *msg, u8 token, int csum)
 {
 	struct mlx5_cmd_mailbox *next = msg->next;
 
 	while (next) {
-		calc_block_sig(next->buf, token);
+		calc_block_sig(next->buf, token, csum);
 		next = next->next;
 	}
 }
 
-static void set_signature(struct mlx5_cmd_work_ent *ent)
+static void set_signature(struct mlx5_cmd_work_ent *ent, int csum)
 {
 	ent->lay->sig = ~xor8_buf(ent->lay, sizeof(*ent->lay));
-	calc_chain_sig(ent->in, ent->token);
-	calc_chain_sig(ent->out, ent->token);
+	calc_chain_sig(ent->in, ent->token, csum);
+	calc_chain_sig(ent->out, ent->token, csum);
 }
 
 static void poll_timeout(struct mlx5_cmd_work_ent *ent)
@@ -539,8 +543,7 @@ static void cmd_work_handler(struct work_struct *work)
 	lay->type = MLX5_PCI_CMD_XPORT;
 	lay->token = ent->token;
 	lay->status_own = CMD_OWNER_HW;
-	if (!cmd->checksum_disabled)
-		set_signature(ent);
+	set_signature(ent, !cmd->checksum_disabled);
 	dump_command(dev, ent, 1);
 	ktime_get_ts(&ent->ts1);
 
@@ -773,8 +776,6 @@ static int mlx5_copy_from_msg(void *to, struct mlx5_cmd_msg *from, int size)
 
 		copy = min_t(int, size, MLX5_CMD_DATA_BLOCK_SIZE);
 		block = next->buf;
-		if (xor8_buf(block, sizeof(*block)) != 0xff)
-			return -EINVAL;
 
 		memcpy(to, block->data, copy);
 		to += copy;
@@ -1361,6 +1362,7 @@ int mlx5_cmd_init(struct mlx5_core_dev *dev)
 		goto err_map;
 	}
 
+	cmd->checksum_disabled = 1;
 	cmd->max_reg_cmds = (1 << cmd->log_sz) - 1;
 	cmd->bitmask = (1 << cmd->max_reg_cmds) - 1;
 

drivers/net/ethernet/mellanox/mlx5/core/main.c

@@ -165,9 +165,7 @@ static int handle_hca_cap(struct mlx5_core_dev *dev)
 	struct mlx5_cmd_set_hca_cap_mbox_in *set_ctx = NULL;
 	struct mlx5_cmd_query_hca_cap_mbox_in query_ctx;
 	struct mlx5_cmd_set_hca_cap_mbox_out set_out;
-	struct mlx5_profile *prof = dev->profile;
 	u64 flags;
-	int csum = 1;
 	int err;
 
 	memset(&query_ctx, 0, sizeof(query_ctx));
@@ -197,20 +195,14 @@ static int handle_hca_cap(struct mlx5_core_dev *dev)
 	memcpy(&set_ctx->hca_cap, &query_out->hca_cap,
 	       sizeof(set_ctx->hca_cap));
 
-	if (prof->mask & MLX5_PROF_MASK_CMDIF_CSUM) {
-		csum = !!prof->cmdif_csum;
-		flags = be64_to_cpu(set_ctx->hca_cap.flags);
-		if (csum)
-			flags |= MLX5_DEV_CAP_FLAG_CMDIF_CSUM;
-		else
-			flags &= ~MLX5_DEV_CAP_FLAG_CMDIF_CSUM;
-
-		set_ctx->hca_cap.flags = cpu_to_be64(flags);
-	}
-
 	if (dev->profile->mask & MLX5_PROF_MASK_QP_SIZE)
 		set_ctx->hca_cap.log_max_qp = dev->profile->log_max_qp;
 
+	flags = be64_to_cpu(query_out->hca_cap.flags);
+	/* disable checksum */
+	flags &= ~MLX5_DEV_CAP_FLAG_CMDIF_CSUM;
+
+	set_ctx->hca_cap.flags = cpu_to_be64(flags);
 	memset(&set_out, 0, sizeof(set_out));
 	set_ctx->hca_cap.log_uar_page_sz = cpu_to_be16(PAGE_SHIFT - 12);
 	set_ctx->hdr.opcode = cpu_to_be16(MLX5_CMD_OP_SET_HCA_CAP);
@@ -225,9 +217,6 @@ static int handle_hca_cap(struct mlx5_core_dev *dev)
 	if (err)
 		goto query_ex;
 
-	if (!csum)
-		dev->cmd.checksum_disabled = 1;
-
 query_ex:
 	kfree(query_out);
 	kfree(set_ctx);

include/linux/mlx5/device.h

@@ -181,7 +181,7 @@ enum {
 	MLX5_DEV_CAP_FLAG_TLP_HINTS	= 1LL << 39,
 	MLX5_DEV_CAP_FLAG_SIG_HAND_OVER	= 1LL << 40,
 	MLX5_DEV_CAP_FLAG_DCT		= 1LL << 41,
-	MLX5_DEV_CAP_FLAG_CMDIF_CSUM	= 1LL << 46,
+	MLX5_DEV_CAP_FLAG_CMDIF_CSUM	= 3LL << 46,
 };
 
 enum {

include/linux/mlx5/driver.h

@@ -747,8 +747,7 @@ static inline u32 mlx5_idx_to_mkey(u32 mkey_idx)
 
 enum {
 	MLX5_PROF_MASK_QP_SIZE		= (u64)1 << 0,
-	MLX5_PROF_MASK_CMDIF_CSUM	= (u64)1 << 1,
-	MLX5_PROF_MASK_MR_CACHE		= (u64)1 << 2,
+	MLX5_PROF_MASK_MR_CACHE		= (u64)1 << 1,
 };
 
 enum {
@@ -758,7 +757,6 @@ enum {
 struct mlx5_profile {
 	u64	mask;
 	u32	log_max_qp;
-	int	cmdif_csum;
 	struct {
 		int	size;
 		int	limit;