firewire: core: add flags member for isochronous context structure

This is minor code refactoring to add a flag member to the isochronous
context structure. At present, it is used only for the option to drop
packets when the context header overflows.

Link: https://lore.kernel.org/r/20260117142823.440811-6-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

drivers/firewire/core-cdev.c

@@ -1064,7 +1064,7 @@ static int ioctl_create_iso_context(struct client *client, union ioctl_arg *arg)
 	if (IS_ERR(context))
 		return PTR_ERR(context);
 	if (client->version < FW_CDEV_VERSION_AUTO_FLUSH_ISO_OVERFLOW)
-		context->drop_overflow_headers = true;
+		context->flags |= FW_ISO_CONTEXT_FLAG_DROP_OVERFLOW_HEADERS;
 
 	// We only support one context at this time.
 	scoped_guard(mutex, &client->iso_context_mutex) {

drivers/firewire/core-iso.c

@@ -151,6 +151,7 @@ struct fw_iso_context *__fw_iso_context_create(struct fw_card *card, int type, i
 	ctx->type = type;
 	ctx->channel = channel;
 	ctx->speed = speed;
+	ctx->flags = 0;
 	ctx->header_size = header_size;
 	ctx->callback = callback;
 	ctx->callback_data = callback_data;

drivers/firewire/ohci.c

@@ -2756,7 +2756,7 @@ static void copy_iso_headers(struct iso_context *ctx, const u32 *dma_hdr)
 	u32 *ctx_hdr;
 
 	if (ctx->sc.header_length + ctx->base.header_size > PAGE_SIZE) {
-		if (ctx->base.drop_overflow_headers)
+		if (ctx->base.flags & FW_ISO_CONTEXT_FLAG_DROP_OVERFLOW_HEADERS)
 			return;
 		flush_iso_completions(ctx, FW_ISO_CONTEXT_COMPLETIONS_CAUSE_HEADER_OVERFLOW);
 	}
@@ -2925,7 +2925,7 @@ static int handle_it_packet(struct context *context,
 	sync_it_packet_for_cpu(context, d);
 
 	if (ctx->sc.header_length + 4 > PAGE_SIZE) {
-		if (ctx->base.drop_overflow_headers)
+		if (ctx->base.flags & FW_ISO_CONTEXT_FLAG_DROP_OVERFLOW_HEADERS)
 			return 1;
 		flush_iso_completions(ctx, FW_ISO_CONTEXT_COMPLETIONS_CAUSE_HEADER_OVERFLOW);
 	}

include/linux/firewire.h

@@ -546,13 +546,17 @@ union fw_iso_callback {
 	fw_iso_mc_callback_t mc;
 };
 
+enum fw_iso_context_flag {
+	FW_ISO_CONTEXT_FLAG_DROP_OVERFLOW_HEADERS = BIT(0),
+};
+
 struct fw_iso_context {
 	struct fw_card *card;
 	struct work_struct work;
 	int type;
 	int channel;
 	int speed;
-	bool drop_overflow_headers;
+	int flags;
 	size_t header_size;
 	union fw_iso_callback callback;
 	void *callback_data;