virtio_blk: set the zone write granularitygrafted

virtblk_read_zoned_limits() reads the write granularity that the device
reports in virtio_blk_zoned_characteristics and assigns it to the
physical block size and to io_min, but never to the limit that is named
after it. queue_limits.zone_write_granularity is left at zero, so
blk_validate_zoned_limits() raises it to the logical block size:

	if (lim->zone_write_granularity < lim->logical_block_size)
		lim->zone_write_granularity = lim->logical_block_size;

A device that reports a granularity coarser than its logical block size,
which is what the field exists to express, therefore has it silently
reduced. A 512e host managed disk passed through to a guest reports a
logical block size of 512 and a write granularity of 4096, and the guest
ends up with a zone write granularity of 512.

bio_split_alignment() returns lim->zone_write_granularity if it is non-zero
and bio_split_io_at() may split a bio with as per bio_split_alignment().
This can real to the write getting rejected by the host drive, as the write
is not aligned to the physical block size.

zonefs also takes its block size from bdev_zone_write_granularity(), so it
would incorrectly use 512 on a disk that requires 4096.

sd_zbc_read_zones() sets the limit from the physical block size for the
same reason. NVMe ZNS and null_blk leave it unset, but the fallback
gives the right answer for them, as their write granularity is the
logical block size. virtio carries a separate value that may exceed it.

Set the zone write granularity from the value that the device reports.

Fixes: 95bfec41bd3d ("virtio-blk: add support for zoned block devices")
Signed-off-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Link: https://patch.msgid.link/20260918140641.2031075-2-cassel@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 304 insertions, 0 deletions

diff --git a/drivers/usb/serial/console.c b/drivers/usb/serial/console.c
new file mode 100644
index 000000000..29f091908
--- /dev/null
+++ b/drivers/usb/serial/console.c
@@ -0,0 +1,304 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * USB Serial Console driver
+ *
+ * Copyright (C) 2001 - 2002 Greg Kroah-Hartman (greg@kroah.com)
+ *
+ * Thanks to Randy Dunlap for the original version of this code.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/console.h>
+#include <linux/serial.h>
+#include <linux/usb.h>
+#include <linux/usb/serial.h>
+
+struct usbcons_info {
+	int			magic;
+	int			break_flag;
+	struct usb_serial_port	*port;
+};
+
+static struct usbcons_info usbcons_info;
+static struct console usbcons;
+
+/*
+ * ------------------------------------------------------------
+ * USB Serial console driver
+ *
+ * Much of the code here is copied from drivers/char/serial.c
+ * and implements a phony serial console in the same way that
+ * serial.c does so that in case some software queries it,
+ * it will get the same results.
+ *
+ * Things that are different from the way the serial port code
+ * does things, is that we call the lower level usb-serial
+ * driver code to initialize the device, and we set the initial
+ * console speeds based on the command line arguments.
+ * ------------------------------------------------------------
+ */
+
+static const struct tty_operations usb_console_fake_tty_ops = {
+};
+
+/*
+ * The parsing of the command line works exactly like the
+ * serial.c code, except that the specifier is "ttyUSB" instead
+ * of "ttyS".
+ */
+static int usb_console_setup(struct console *co, char *options)
+{
+	struct usbcons_info *info = &usbcons_info;
+	int baud = 9600;
+	int bits = 8;
+	int parity = 'n';
+	int doflow = 0;
+	int cflag = CREAD | HUPCL | CLOCAL;
+	char *s;
+	struct usb_serial *serial;
+	struct usb_serial_port *port;
+	int retval;
+	struct tty_struct *tty = NULL;
+	struct ktermios dummy;
+
+	if (options) {
+		baud = simple_strtoul(options, NULL, 10);
+		s = options;
+		while (*s >= '0' && *s <= '9')
+			s++;
+		if (*s)
+			parity = *s++;
+		if (*s)
+			bits   = *s++ - '0';
+		if (*s)
+			doflow = (*s++ == 'r');
+	}
+
+	/* Sane default */
+	if (baud == 0)
+		baud = 9600;
+
+	switch (bits) {
+	case 7:
+		cflag |= CS7;
+		break;
+	default:
+	case 8:
+		cflag |= CS8;
+		break;
+	}
+	switch (parity) {
+	case 'o': case 'O':
+		cflag |= PARODD;
+		break;
+	case 'e': case 'E':
+		cflag |= PARENB;
+		break;
+	}
+
+	if (doflow)
+		cflag |= CRTSCTS;
+
+	/*
+	 * no need to check the index here: if the index is wrong, console
+	 * code won't call us
+	 */
+	port = usb_serial_port_get_by_minor(co->index);
+	if (port == NULL) {
+		/* no device is connected yet, sorry :( */
+		pr_err("No USB device connected to ttyUSB%i\n", co->index);
+		return -ENODEV;
+	}
+	serial = port->serial;
+
+	retval = usb_autopm_get_interface(serial->interface);
+	if (retval)
+		goto error_get_interface;
+
+	tty_port_tty_set(&port->port, NULL);
+
+	info->port = port;
+
+	++port->port.count;
+	if (!tty_port_initialized(&port->port)) {
+		if (serial->type->set_termios) {
+			/*
+			 * allocate a fake tty so the driver can initialize
+			 * the termios structure, then later call set_termios to
+			 * configure according to command line arguments
+			 */
+			tty = kzalloc_obj(*tty);
+			if (!tty) {
+				retval = -ENOMEM;
+				goto reset_open_count;
+			}
+			kref_init(&tty->kref);
+			tty->driver = usb_serial_tty_driver;
+			tty->index = co->index;
+			init_ldsem(&tty->ldisc_sem);
+			spin_lock_init(&tty->files_lock);
+			INIT_LIST_HEAD(&tty->tty_files);
+			kref_get(&tty->driver->kref);
+			__module_get(tty->driver->owner);
+			tty->ops = &usb_console_fake_tty_ops;
+			tty_init_termios(tty);
+			tty_port_tty_set(&port->port, tty);
+		}
+
+		/* only call the device specific open if this
+		 * is the first time the port is opened */
+		retval = serial->type->open(NULL, port);
+		if (retval) {
+			dev_err(&port->dev, "could not open USB console port\n");
+			goto fail;
+		}
+
+		if (serial->type->set_termios) {
+			tty->termios.c_cflag = cflag;
+			tty_termios_encode_baud_rate(&tty->termios, baud, baud);
+			memset(&dummy, 0, sizeof(struct ktermios));
+			serial->type->set_termios(tty, port, &dummy);
+
+			tty_port_tty_set(&port->port, NULL);
+			tty_save_termios(tty);
+			tty_kref_put(tty);
+		}
+		tty_port_set_initialized(&port->port, true);
+	}
+	/* Now that any required fake tty operations are completed restore
+	 * the tty port count */
+	--port->port.count;
+	/* The console is special in terms of closing the device so
+	 * indicate this port is now acting as a system console. */
+	port->port.console = 1;
+
+	mutex_unlock(&serial->disc_mutex);
+	return retval;
+
+ fail:
+	tty_port_tty_set(&port->port, NULL);
+	tty_kref_put(tty);
+ reset_open_count:
+	port->port.count = 0;
+	info->port = NULL;
+	usb_autopm_put_interface(serial->interface);
+ error_get_interface:
+	mutex_unlock(&serial->disc_mutex);
+	usb_serial_put(serial);
+	return retval;
+}
+
+static void usb_console_write(struct console *co,
+					const char *buf, unsigned count)
+{
+	static struct usbcons_info *info = &usbcons_info;
+	struct usb_serial_port *port = info->port;
+	struct usb_serial *serial;
+	int retval = -ENODEV;
+
+	if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED)
+		return;
+	serial = port->serial;
+
+	if (count == 0)
+		return;
+
+	dev_dbg(&port->dev, "%s - %d byte(s)\n", __func__, count);
+
+	if (!port->port.console) {
+		dev_dbg(&port->dev, "%s - port not opened\n", __func__);
+		return;
+	}
+
+	while (count) {
+		unsigned int i;
+		unsigned int lf;
+		/* search for LF so we can insert CR if necessary */
+		for (i = 0, lf = 0 ; i < count ; i++) {
+			if (*(buf + i) == 10) {
+				lf = 1;
+				i++;
+				break;
+			}
+		}
+		/* pass on to the driver specific version of this function if
+		   it is available */
+		retval = serial->type->write(NULL, port, buf, i);
+		dev_dbg(&port->dev, "%s - write: %d\n", __func__, retval);
+		if (lf) {
+			/* append CR after LF */
+			unsigned char cr = 13;
+			retval = serial->type->write(NULL, port, &cr, 1);
+			dev_dbg(&port->dev, "%s - write cr: %d\n",
+							__func__, retval);
+		}
+		buf += i;
+		count -= i;
+	}
+}
+
+static struct tty_driver *usb_console_device(struct console *co, int *index)
+{
+	struct tty_driver **p = (struct tty_driver **)co->data;
+
+	if (!*p)
+		return NULL;
+
+	*index = co->index;
+	return *p;
+}
+
+static struct console usbcons = {
+	.name =		"ttyUSB",
+	.write =	usb_console_write,
+	.device =	usb_console_device,
+	.setup =	usb_console_setup,
+	.flags =	CON_PRINTBUFFER,
+	.index =	-1,
+	.data = 	&usb_serial_tty_driver,
+};
+
+void usb_serial_console_disconnect(struct usb_serial *serial)
+{
+	if (serial->port[0] && serial->port[0] == usbcons_info.port) {
+		usb_serial_console_exit();
+		usb_serial_put(serial);
+	}
+}
+
+void usb_serial_console_init(int minor)
+{
+	if (minor == 0) {
+		/*
+		 * Call register_console() if this is the first device plugged
+		 * in.  If we call it earlier, then the callback to
+		 * console_setup() will fail, as there is not a device seen by
+		 * the USB subsystem yet.
+		 */
+		/*
+		 * Register console.
+		 * NOTES:
+		 * console_setup() is called (back) immediately (from
+		 * register_console). console_write() is called immediately
+		 * from register_console iff CON_PRINTBUFFER is set in flags.
+		 */
+		pr_debug("registering the USB serial console.\n");
+		register_console(&usbcons);
+	}
+}
+
+void usb_serial_console_exit(void)
+{
+	if (usbcons_info.port) {
+		unregister_console(&usbcons);
+		usbcons_info.port->port.console = 0;
+		usbcons_info.port = NULL;
+	}
+}
+