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, 162 insertions, 0 deletions

diff --git a/include/net/lapb.h b/include/net/lapb.h
new file mode 100644
index 000000000..6c0742064
--- /dev/null
+++ b/include/net/lapb.h
@@ -0,0 +1,162 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LAPB_H
+#define _LAPB_H 
+#include <linux/lapb.h>
+#include <linux/refcount.h>
+
+#define	LAPB_HEADER_LEN MAX_HEADER		/* LAPB over Ethernet + a bit more */
+
+#define	LAPB_ACK_PENDING_CONDITION	0x01
+#define	LAPB_REJECT_CONDITION		0x02
+#define	LAPB_PEER_RX_BUSY_CONDITION	0x04
+
+/* Control field templates */
+#define	LAPB_I		0x00	/* Information frames */
+#define	LAPB_S		0x01	/* Supervisory frames */
+#define	LAPB_U		0x03	/* Unnumbered frames */
+
+#define	LAPB_RR		0x01	/* Receiver ready */
+#define	LAPB_RNR	0x05	/* Receiver not ready */
+#define	LAPB_REJ	0x09	/* Reject */
+
+#define	LAPB_SABM	0x2F	/* Set Asynchronous Balanced Mode */
+#define	LAPB_SABME	0x6F	/* Set Asynchronous Balanced Mode Extended */
+#define	LAPB_DISC	0x43	/* Disconnect */
+#define	LAPB_DM		0x0F	/* Disconnected mode */
+#define	LAPB_UA		0x63	/* Unnumbered acknowledge */
+#define	LAPB_FRMR	0x87	/* Frame reject */
+
+#define LAPB_ILLEGAL	0x100	/* Impossible to be a real frame type */
+
+#define	LAPB_SPF	0x10	/* Poll/final bit for standard LAPB */
+#define	LAPB_EPF	0x01	/* Poll/final bit for extended LAPB */
+
+#define	LAPB_FRMR_W	0x01	/* Control field invalid	*/
+#define	LAPB_FRMR_X	0x02	/* I field invalid		*/
+#define	LAPB_FRMR_Y	0x04	/* I field too long		*/
+#define	LAPB_FRMR_Z	0x08	/* Invalid N(R)			*/
+
+#define	LAPB_POLLOFF	0
+#define	LAPB_POLLON	1
+
+/* LAPB C-bit */
+#define LAPB_COMMAND	1
+#define LAPB_RESPONSE	2
+
+#define	LAPB_ADDR_A	0x03
+#define	LAPB_ADDR_B	0x01
+#define	LAPB_ADDR_C	0x0F
+#define	LAPB_ADDR_D	0x07
+
+/* Define Link State constants. */
+enum {
+	LAPB_STATE_0,	/* Disconnected State		*/
+	LAPB_STATE_1,	/* Awaiting Connection State	*/
+	LAPB_STATE_2,	/* Awaiting Disconnection State	*/
+	LAPB_STATE_3,	/* Data Transfer State		*/
+	LAPB_STATE_4	/* Frame Reject State		*/
+};
+
+#define	LAPB_DEFAULT_MODE		(LAPB_STANDARD | LAPB_SLP | LAPB_DTE)
+#define	LAPB_DEFAULT_WINDOW		7		/* Window=7 */
+#define	LAPB_DEFAULT_T1			(5 * HZ)	/* T1=5s    */
+#define	LAPB_DEFAULT_T2			(1 * HZ)	/* T2=1s    */
+#define	LAPB_DEFAULT_N2			20		/* N2=20    */
+
+#define	LAPB_SMODULUS	8
+#define	LAPB_EMODULUS	128
+
+/*
+ *	Information about the current frame.
+ */
+struct lapb_frame {
+	unsigned short		type;		/* Parsed type		*/
+	unsigned short		nr, ns;		/* N(R), N(S)		*/
+	unsigned char		cr;		/* Command/Response	*/
+	unsigned char		pf;		/* Poll/Final		*/
+	unsigned char		control[2];	/* Original control data*/
+};
+
+/*
+ *	The per LAPB connection control structure.
+ */
+struct lapb_cb {
+	struct list_head	node;
+	struct net_device	*dev;
+
+	/* Link status fields */
+	unsigned int		mode;
+	unsigned char		state;
+	unsigned short		vs, vr, va;
+	unsigned char		condition;
+	unsigned short		n2, n2count;
+	unsigned short		t1, t2;
+	struct timer_list	t1timer, t2timer;
+	bool			t1timer_running, t2timer_running;
+
+	/* Internal control information */
+	struct sk_buff_head	write_queue;
+	struct sk_buff_head	ack_queue;
+	unsigned char		window;
+	const struct lapb_register_struct *callbacks;
+
+	/* FRMR control information */
+	struct lapb_frame	frmr_data;
+	unsigned char		frmr_type;
+
+	spinlock_t		lock;
+	refcount_t		refcnt;
+};
+
+/* lapb_iface.c */
+void lapb_connect_confirmation(struct lapb_cb *lapb, int);
+void lapb_connect_indication(struct lapb_cb *lapb, int);
+void lapb_disconnect_confirmation(struct lapb_cb *lapb, int);
+void lapb_disconnect_indication(struct lapb_cb *lapb, int);
+int lapb_data_indication(struct lapb_cb *lapb, struct sk_buff *);
+int lapb_data_transmit(struct lapb_cb *lapb, struct sk_buff *);
+
+/* lapb_in.c */
+void lapb_data_input(struct lapb_cb *lapb, struct sk_buff *);
+
+/* lapb_out.c */
+void lapb_kick(struct lapb_cb *lapb);
+void lapb_transmit_buffer(struct lapb_cb *lapb, struct sk_buff *, int);
+void lapb_establish_data_link(struct lapb_cb *lapb);
+void lapb_enquiry_response(struct lapb_cb *lapb);
+void lapb_timeout_response(struct lapb_cb *lapb);
+void lapb_check_iframes_acked(struct lapb_cb *lapb, unsigned short);
+void lapb_check_need_response(struct lapb_cb *lapb, int, int);
+
+/* lapb_subr.c */
+void lapb_clear_queues(struct lapb_cb *lapb);
+void lapb_frames_acked(struct lapb_cb *lapb, unsigned short);
+void lapb_requeue_frames(struct lapb_cb *lapb);
+int lapb_validate_nr(struct lapb_cb *lapb, unsigned short);
+int lapb_decode(struct lapb_cb *lapb, struct sk_buff *, struct lapb_frame *);
+void lapb_send_control(struct lapb_cb *lapb, int, int, int);
+void lapb_transmit_frmr(struct lapb_cb *lapb);
+
+/* lapb_timer.c */
+void lapb_start_t1timer(struct lapb_cb *lapb);
+void lapb_start_t2timer(struct lapb_cb *lapb);
+void lapb_stop_t1timer(struct lapb_cb *lapb);
+void lapb_stop_t2timer(struct lapb_cb *lapb);
+int lapb_t1timer_running(struct lapb_cb *lapb);
+
+/*
+ * Debug levels.
+ *	0 = Off
+ *	1 = State Changes
+ *	2 = Packets I/O and State Changes
+ *	3 = Hex dumps, Packets I/O and State Changes.
+ */
+#define	LAPB_DEBUG	0
+
+#define lapb_dbg(level, fmt, ...)			\
+do {							\
+	if (level < LAPB_DEBUG)				\
+		pr_debug(fmt, ##__VA_ARGS__);		\
+} while (0)
+
+#endif