Re: [PATCH v5 13/13] tty: gunyah: Add tty console driver for RM Console Services

From: Jiri Slaby
Date: Tue Oct 11 2022 - 02:02:49 EST


On 11. 10. 22, 2:08, Elliot Berman wrote:
Gunyah provides a console for each VM using the VM console resource
manager APIs. This driver allows console data from other
VMs to be accessed via a TTY device and exports a console device to dump
Linux's own logs to our console.
...
+struct rm_cons_drv_data {
+ struct tty_driver *tty_driver;
+ struct device *dev;
+
+ spinlock_t ports_lock;
+ struct rm_cons_port *ports[RM_CONS_TTY_ADAPATERS];
+
+ struct notifier_block rm_cons_notif;
+ struct console console;
+
+ /* below are for printk console.
+ * gh_rm_console_* calls will sleep and console_write can be called from
+ * atomic ctx. Two xmit buffers are used. The active buffer is tracked with
+ * co_xmit_idx. Writes go into the co_xmit_buf[co_xmit_idx] buffer.
+ * A work is scheduled to flush the bytes. The work will swap the active buffer
+ * and write out the other buffer.
+ */

Ugh, why? This is too ugly and unnecessary. What about passing the kfifo to gh_rm_console_write() instead? You do memcpy() there anyway.

+ char *co_xmit_buf[2];
+ int co_xmit_idx;
+ unsigned int co_xmit_count;
+ spinlock_t co_xmit_lock;
+ struct work_struct co_flush_work;
+};
+
+static int rm_cons_notif_handler(struct notifier_block *nb, unsigned long cmd, void *data)
+{
+ int count, i;
+ struct rm_cons_port *rm_port = NULL;
+ struct tty_port *tty_port = NULL;
+ struct rm_cons_drv_data *cons_data =
+ container_of(nb, struct rm_cons_drv_data, rm_cons_notif);
+ const struct gh_rm_notification *notif = data;
+ struct gh_rm_notif_vm_console_chars const * const msg = notif->buff;

So you did not comment on/address all my notes?

--
js