Module Name: src
Committed By: riastradh
Date: Mon May 22 15:00:17 UTC 2023
Modified Files:
src/sys/dev/dkwedge: dk.c
Log Message:
dk(4): Add locking notes.
To generate a diff of this commit:
cvs rdiff -u -r1.170 -r1.171 src/sys/dev/dkwedge/dk.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/dev/dkwedge/dk.c
diff -u src/sys/dev/dkwedge/dk.c:1.170 src/sys/dev/dkwedge/dk.c:1.171
--- src/sys/dev/dkwedge/dk.c:1.170 Mon May 22 15:00:06 2023
+++ src/sys/dev/dkwedge/dk.c Mon May 22 15:00:17 2023
@@ -1,4 +1,4 @@
-/* $NetBSD: dk.c,v 1.170 2023/05/22 15:00:06 riastradh Exp $ */
+/* $NetBSD: dk.c,v 1.171 2023/05/22 15:00:17 riastradh Exp $ */
/*-
* Copyright (c) 2004, 2005, 2006, 2007 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: dk.c,v 1.170 2023/05/22 15:00:06 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: dk.c,v 1.171 2023/05/22 15:00:17 riastradh Exp $");
#ifdef _KERNEL_OPT
#include "opt_dkwedge.h"
@@ -70,29 +70,65 @@ typedef enum {
DKW_STATE_DEAD = 666
} dkwedge_state_t;
+/*
+ * Lock order:
+ *
+ * sc->sc_dk.dk_openlock
+ * => sc->sc_parent->dk_rawlock
+ * => sc->sc_parent->dk_openlock
+ * => dkwedges_lock
+ * => sc->sc_sizelock
+ *
+ * Locking notes:
+ *
+ * W dkwedges_lock
+ * D device reference
+ * O sc->sc_dk.dk_openlock
+ * P sc->sc_parent->dk_openlock
+ * R sc->sc_parent->dk_rawlock
+ * S sc->sc_sizelock
+ * I sc->sc_iolock
+ * $ stable after initialization
+ * 1 used only by a single thread
+ *
+ * x&y means both x and y must be held to write (with a write lock if
+ * one is rwlock), and either x or y must be held to read.
+ */
+
struct dkwedge_softc {
- device_t sc_dev; /* pointer to our pseudo-device */
- struct cfdata sc_cfdata; /* our cfdata structure */
- uint8_t sc_wname[128]; /* wedge name (Unicode, UTF-8) */
+ device_t sc_dev; /* P&W: pointer to our pseudo-device */
+ /* sc_dev is also stable while device is referenced */
+ struct cfdata sc_cfdata; /* 1: our cfdata structure */
+ uint8_t sc_wname[128]; /* $: wedge name (Unicode, UTF-8) */
dkwedge_state_t sc_state; /* state this wedge is in */
+ /* stable while device is referenced */
+ /* used only in assertions when stable, and in dump in ddb */
- struct disk *sc_parent; /* parent disk */
- daddr_t sc_offset; /* LBA offset of wedge in parent */
+ struct disk *sc_parent; /* $: parent disk */
+ /* P: sc_parent->dk_openmask */
+ /* P: sc_parent->dk_nwedges */
+ /* P: sc_parent->dk_wedges */
+ /* R: sc_parent->dk_rawopens */
+ /* R: sc_parent->dk_rawvp (also stable while wedge is open) */
+ daddr_t sc_offset; /* $: LBA offset of wedge in parent */
krwlock_t sc_sizelock;
- uint64_t sc_size; /* size of wedge in blocks */
- char sc_ptype[32]; /* partition type */
- dev_t sc_pdev; /* cached parent's dev_t */
- /* link on parent's wedge list */
+ uint64_t sc_size; /* S: size of wedge in blocks */
+ char sc_ptype[32]; /* $: partition type */
+ dev_t sc_pdev; /* $: cached parent's dev_t */
+ /* P: link on parent's wedge list */
LIST_ENTRY(dkwedge_softc) sc_plink;
struct disk sc_dk; /* our own disk structure */
- struct bufq_state *sc_bufq; /* buffer queue */
- struct callout sc_restart_ch; /* callout to restart I/O */
+ /* O&R: sc_dk.dk_bopenmask */
+ /* O&R: sc_dk.dk_copenmask */
+ /* O&R: sc_dk.dk_openmask */
+ struct bufq_state *sc_bufq; /* $: buffer queue */
+ struct callout sc_restart_ch; /* I: callout to restart I/O */
kmutex_t sc_iolock;
- bool sc_iostop; /* don't schedule restart */
- int sc_mode; /* parent open mode */
+ bool sc_iostop; /* I: don't schedule restart */
+ int sc_mode; /* O&R: parent open mode */
};
static int dkwedge_match(device_t, cfdata_t, void *);
