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dk(4): Add locking notes.

This commit is contained in:
riastradh 2023-05-22 15:00:17 +00:00
parent f135754f8b
commit 2e4b9f2ad5
1 changed files with 51 additions and 15 deletions
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66
sys/dev/dkwedge/dk.c
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@ -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 *);