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diff --git a/share/man/man4/dtrace_cam.4 b/share/man/man4/dtrace_cam.4
--- a/share/man/man4/dtrace_cam.4
+++ b/share/man/man4/dtrace_cam.4
@@ -2,22 +2,38 @@
.\"
.\" SPDX-License-Identifier: BSD-2-Clause
.\"
-.Dd May 7, 2026
+.Dd July 29, 2026
.Dt DTRACE_CAM 4
.Os
.Sh NAME
.Nm dtrace_cam
.Nd a DTrace provider for tracing events related to CAM
.Sh SYNOPSIS
-.Fn cam::xpt:action "union ccb *ccn"
+.Fn cam::xpt:action "union ccb *ccb"
.Fn cam::xpt:done "union ccb *ccb"
-.Fn cam::xpt:async-cb "void *cbarg" "uint32_t async_code" "struct cam_path *path" "void *async_Arg"
+a.Fn cam::xpt:async-cb "void *cbarg" "uint32_t async_code" "struct cam_path *path" "void *async_arg"
+.Fn cam::periph:error "union ccb *ccb" "cam_flags camflags" "uint32_t sense_flags"
+.Fn cam::da:error "union ccb *ccb" "uint32_t cam_flags" "uint32_t sense_flags"
+.Fn cam::ada:error "union ccb *ccb" "uint32_t cam_flags" "uint32_t sense_flags"
+.Fn cam::nda:error "union ccb *ccb" "uint32_t cam_flags" "uint32_t sense_flags"
+.Fn cam::sdda:error "union ccb *ccb" "uint32_t cam_flags" "uint32_t sense_flags"
+.Fn cam::periph:recovery "union ccb *ccb" "int error"
+.Fn cam::da:recovery "union ccb *ccb" "int error"
+.Fn cam::ada:recovery "union ccb *ccb" "int error"
+.Fn cam::nda:recovery "union ccb *ccb" "int error"
+.Fn cam::sdda:recovery "union ccb *ccb" "int error"
+.Fn cam::periph:invalidate "struct cam_periph *periph"
+.Fn cam::periph:hold-boot "struct cam_periph *periph"
+.Fn cam::periph:release-boot "struct cam_periph *periph"
+.Fn cam::xpt:bus-register "struct cam_sim *sim" "path_id_t path_id"
+.Fn cam::xpt:hold-boot "int buses_to_config"
+.Fn cam::xpt:release-boot "int buses_to_config"
.Sh DESCRIPTION
The
.Nm cam
provider allows the tracing of CAM events.
The
-.Fn cam::xpt_action
+.Fn cam::xpt::action
probe fires when a CAM Control Block (ccb) is submitted to a CAM SIM driver.
The
.Fn cam::xpt:done
@@ -25,6 +41,122 @@
The
.Fn cam::xpt:async-cb
probe fires just before an async callback is called.
+The
+.Fn cam::periph:error
+probe fires on entry to
+.Fn cam_periph_error ,
+the generic CAM peripheral driver error handler, before any error
+recovery or retry decisions are made.
+The
+.Fn cam::da:error ,
+.Fn cam::ada:error ,
+.Fn cam::nda:error ,
+and
+.Fn cam::sdda:error
+probes fire on entry to the
+.Xr da 4 ,
+.Xr ada 4 ,
+.Xr nda 4 ,
+and sdda
+.Pq Xr mmc 4
+peripheral drivers' own error handlers, before they call
+.Fn cam_periph_error
+or otherwise process the failing ccb.
+.Pp
+The
+.Fn cam::periph:recovery
+probe fires once
+.Fn cam_periph_error
+has decided how to dispose of the failing ccb, reporting that decision
+as
+.Fa error :
+0 means the ccb is being treated as successful,
+.Dv ERESTART
+means the request is being retried, and any other value is the
+.Xr errno 2
+the request is failing with.
+Of those,
+.Er EIO
+means only this request is being failed,
+while
+.Er ENXIO
+means the device itself is now being treated as gone
+(a selection timeout, or an error seen after the peripheral was
+already invalidated).
+Other errno values can appear as well: CAM_SCSI_STATUS_ERROR handling
+maps specific SCSI sense key/ASC/ASCQ combinations to whatever errno
+is most appropriate
+.Pq Er EBUSY , Er ENOSPC , Er EINVAL , No and others
+via the table in
+.Pa sys/cam/scsi/scsi_all.c .
+The
+.Fn cam::da:recovery ,
+.Fn cam::ada:recovery ,
+.Fn cam::nda:recovery ,
+and
+.Fn cam::sdda:recovery
+probes report the same
+.Fa error
+decision from the corresponding peripheral driver's own error handler,
+which may resolve the error itself (for example
+.Xr da 4 Ns 's
+automatic READ/WRITE(6)-to-(10) upgrade) before ever calling
+.Fn cam_periph_error .
+The
+.Fn cam::periph:invalidate
+probe fires from
+.Fn cam_periph_invalidate
+when a peripheral is actually torn down as a result of an
+unrecoverable error, regardless of which peripheral driver or code
+path triggered it.
+.Pp
+The
+.Fn cam::periph:hold-boot
+and
+.Fn cam::periph:release-boot
+probes fire from
+.Fn cam_periph_hold_boot
+and
+.Fn cam_periph_release_boot ,
+reporting the
+.Vt cam_periph
+taking or releasing its own, per-peripheral root-mount hold, which is
+keyed by
+.Fa periph->periph_name
+(for example
+.Sq da
+or
+.Sq ada ) .
+Since the probe itself is necessarily generic
+.Pq SDT probe names are fixed at compile time, not runtime ,
+a consumer wanting to filter by peripheral type should match on
+.Fa periph->periph_name
+in the enabling's predicate, for example
+.Li stringof(args[0]->periph_name) == \(dqda\(dq .
+.Pp
+The
+.Fn cam::xpt:bus-register
+probe fires from
+.Fn xpt_bus_register
+once a new bus has been assigned a
+.Fa path_id
+and linked into the list of known busses, reporting the
+.Vt cam_sim
+being registered and that
+.Fa path_id .
+The
+.Fn cam::xpt:hold-boot
+and
+.Fn cam::xpt:release-boot
+probes report the CAM subsystem's shared boot-hold refcount
+.Pq Va xsoftc.buses_to_config
+immediately after it is incremented or decremented, respectively.
+This one refcount is shared by every bus's initial scan
+.Pq via Fn xpt_rescan
+as well as by peripheral drivers' own startup bookkeeping, so root
+mount can remain blocked on it long after any one contributor has
+finished; tracing both probes together shows exactly which holds are
+still outstanding and for how long.
.Sh SEE ALSO
.Xr dtrace 1 ,
.Xr cam 4 ,
diff --git a/sys/cam/ata/ata_da.c b/sys/cam/ata/ata_da.c
--- a/sys/cam/ata/ata_da.c
+++ b/sys/cam/ata/ata_da.c
@@ -68,6 +68,10 @@
#include <cam/ata/ata_all.h>
+/* SDT Probes */
+SDT_PROBE_DEFINE3(cam, , ada, error, "union ccb *", "uint32_t", "uint32_t");
+SDT_PROBE_DEFINE2(cam, , ada, recovery, "union ccb *", "int");
+
#ifdef _KERNEL
#define ATA_MAX_28BIT_LBA 268435455UL
@@ -3479,6 +3483,10 @@
static int
adaerror(union ccb *ccb, uint32_t cam_flags, uint32_t sense_flags)
{
+ int error;
+
+ CAM_PROBE3(ada, error, ccb, cam_flags, sense_flags);
+
#ifdef CAM_IO_STATS
struct ada_softc *softc;
struct cam_periph *periph;
@@ -3503,7 +3511,9 @@
}
#endif
- return(cam_periph_error(ccb, cam_flags, sense_flags));
+ error = cam_periph_error(ccb, cam_flags, sense_flags);
+ CAM_PROBE2(ada, recovery, ccb, error);
+ return (error);
}
static void
diff --git a/sys/cam/cam.h b/sys/cam/cam.h
--- a/sys/cam/cam.h
+++ b/sys/cam/cam.h
@@ -388,6 +388,11 @@
SDT_PROBE3(cam, , group, probe, arg0, arg1, arg2)
#define CAM_PROBE4(group, probe, arg0, arg1, arg2, arg3) \
SDT_PROBE4(cam, , group, probe, arg0, arg1, arg2, arg3)
+#else
+#define CAM_PROBE1(group, probe, arg0)
+#define CAM_PROBE2(group, probe, arg0, arg1)
+#define CAM_PROBE3(group, probe, arg0, arg1, arg2)
+#define CAM_PROBE4(group, probe, arg0, arg1, arg2, arg3)
#endif
union ccb;
struct sbuf;
diff --git a/sys/cam/cam_periph.c b/sys/cam/cam_periph.c
--- a/sys/cam/cam_periph.c
+++ b/sys/cam/cam_periph.c
@@ -61,6 +61,14 @@
#include <cam/scsi/scsi_message.h>
#include <cam/scsi/scsi_pass.h>
+/* SDT Probes */
+SDT_PROBE_DEFINE3(cam, , periph, error, "union ccb *", "cam_flags",
+ "uint32_t");
+SDT_PROBE_DEFINE2(cam, , periph, recovery, "union ccb *", "int");
+SDT_PROBE_DEFINE1(cam, , periph, invalidate, "struct cam_periph *");
+SDT_PROBE_DEFINE1(cam, , periph, hold__boot, "struct cam_periph *");
+SDT_PROBE_DEFINE1(cam, , periph, release__boot, "struct cam_periph *");
+
static u_int camperiphnextunit(struct periph_driver *p_drv,
u_int newunit, bool wired,
path_id_t pathid, target_id_t target,
@@ -536,6 +544,7 @@
cam_periph_hold_boot(struct cam_periph *periph)
{
+ CAM_PROBE1(periph, hold__boot, periph);
root_mount_hold_token(periph->periph_name, &periph->periph_rootmount);
}
@@ -543,6 +552,7 @@
cam_periph_release_boot(struct cam_periph *periph)
{
+ CAM_PROBE1(periph, release__boot, periph);
root_mount_rel(&periph->periph_rootmount);
}
@@ -690,6 +700,7 @@
if ((periph->flags & CAM_PERIPH_INVALID) != 0)
return;
+ CAM_PROBE1(periph, invalidate, periph);
CAM_DEBUG(periph->path, CAM_DEBUG_INFO, ("Periph invalidated\n"));
if (!rebooting)
cam_periph_invalidate_devctl(periph);
@@ -1893,6 +1904,8 @@
int error, openings, devctl_err;
uint32_t action, relsim_flags, timeout;
+ CAM_PROBE3(periph, error, ccb, camflags, sense_flags);
+
action = SSQ_PRINT_SENSE;
periph = xpt_path_periph(ccb->ccb_h.path);
action_string = NULL;
@@ -2122,6 +2135,7 @@
/*getcount_only*/0);
}
+ CAM_PROBE2(periph, recovery, ccb, error);
return (error);
}
diff --git a/sys/cam/cam_xpt.c b/sys/cam/cam_xpt.c
--- a/sys/cam/cam_xpt.c
+++ b/sys/cam/cam_xpt.c
@@ -75,6 +75,9 @@
SDT_PROBE_DEFINE1(cam, , xpt, done, "union ccb *");
SDT_PROBE_DEFINE4(cam, , xpt, async__cb, "void *", "uint32_t",
"struct cam_path *", "void *");
+SDT_PROBE_DEFINE2(cam, , xpt, bus__register, "struct cam_sim *", "path_id_t");
+SDT_PROBE_DEFINE1(cam, , xpt, hold__boot, "int");
+SDT_PROBE_DEFINE1(cam, , xpt, release__boot, "int");
/* Wild guess based on not wanting to grow the stack too much */
#define XPT_PRINT_MAXLEN 512
@@ -3941,6 +3944,8 @@
xsoftc.bus_generation++;
xpt_unlock_buses();
+ CAM_PROBE2(xpt, bus__register, sim, new_bus->path_id);
+
/*
* Set a default transport so that a PATH_INQ can be issued to
* the SIM. This will then allow for probing and attaching of
@@ -5092,6 +5097,7 @@
if (xsoftc.buses_to_config++ == 0)
root_mount_hold_token("CAM", &xsoftc.xpt_rootmount);
+ CAM_PROBE1(xpt, hold__boot, xsoftc.buses_to_config);
}
void
@@ -5108,10 +5114,13 @@
{
xpt_lock_buses();
- if (--xsoftc.buses_to_config == 0) {
+ --xsoftc.buses_to_config;
+ CAM_PROBE1(xpt, release__boot, xsoftc.buses_to_config);
+ if (xsoftc.buses_to_config == 0) {
if (xsoftc.buses_config_done == 0) {
xsoftc.buses_config_done = 1;
xsoftc.buses_to_config++;
+ CAM_PROBE1(xpt, hold__boot, xsoftc.buses_to_config);
TASK_INIT(&xsoftc.boot_task, 0, xpt_finishconfig_task,
NULL);
taskqueue_enqueue(taskqueue_thread, &xsoftc.boot_task);
diff --git a/sys/cam/mmc/mmc_da.c b/sys/cam/mmc/mmc_da.c
--- a/sys/cam/mmc/mmc_da.c
+++ b/sys/cam/mmc/mmc_da.c
@@ -74,6 +74,10 @@
#include <cam/mmc/mmc_all.h>
+/* SDT Probes */
+SDT_PROBE_DEFINE3(cam, , sdda, error, "union ccb *", "uint32_t", "uint32_t");
+SDT_PROBE_DEFINE2(cam, , sdda, recovery, "union ccb *", "int");
+
#ifdef _KERNEL
typedef enum {
@@ -1983,7 +1987,13 @@
static int
sddaerror(union ccb *ccb, uint32_t cam_flags, uint32_t sense_flags)
{
- return(cam_periph_error(ccb, cam_flags, sense_flags));
+ int error;
+
+ CAM_PROBE3(sdda, error, ccb, cam_flags, sense_flags);
+
+ error = cam_periph_error(ccb, cam_flags, sense_flags);
+ CAM_PROBE2(sdda, recovery, ccb, error);
+ return (error);
}
static int
diff --git a/sys/cam/nvme/nvme_da.c b/sys/cam/nvme/nvme_da.c
--- a/sys/cam/nvme/nvme_da.c
+++ b/sys/cam/nvme/nvme_da.c
@@ -65,6 +65,10 @@
#include <cam/nvme/nvme_all.h>
+/* SDT Probes */
+SDT_PROBE_DEFINE3(cam, , nda, error, "union ccb *", "uint32_t", "uint32_t");
+SDT_PROBE_DEFINE2(cam, , nda, recovery, "union ccb *", "int");
+
typedef enum {
NDA_STATE_NORMAL
} nda_state;
@@ -1371,6 +1375,10 @@
static int
ndaerror(union ccb *ccb, uint32_t cam_flags, uint32_t sense_flags)
{
+ int error;
+
+ CAM_PROBE3(nda, error, ccb, cam_flags, sense_flags);
+
#ifdef CAM_IO_STATS
struct nda_softc *softc;
struct cam_periph *periph;
@@ -1395,7 +1403,9 @@
break;
}
- return(cam_periph_error(ccb, cam_flags, sense_flags));
+ error = cam_periph_error(ccb, cam_flags, sense_flags);
+ CAM_PROBE2(nda, recovery, ccb, error);
+ return (error);
}
/*
diff --git a/sys/cam/scsi/scsi_da.c b/sys/cam/scsi/scsi_da.c
--- a/sys/cam/scsi/scsi_da.c
+++ b/sys/cam/scsi/scsi_da.c
@@ -72,6 +72,10 @@
#include <cam/scsi/scsi_da.h>
#ifdef _KERNEL
+/* SDT Probes */
+SDT_PROBE_DEFINE3(cam, , da, error, "union ccb *", "uint32_t", "uint32_t");
+SDT_PROBE_DEFINE2(cam, , da, recovery, "union ccb *", "int");
+
/*
* Note that there are probe ordering dependencies here. The order isn't
* controlled by this enumeration, but by explicit state transitions in
@@ -6255,6 +6259,8 @@
struct cam_periph *periph;
int error, error_code, sense_key, asc, ascq;
+ CAM_PROBE3(da, error, ccb, cam_flags, sense_flags);
+
#if defined(BUF_TRACKING) || defined(FULL_BUF_TRACKING)
if (ccb->csio.bio != NULL)
biotrack(ccb->csio.bio, __func__);
@@ -6320,8 +6326,10 @@
disk_media_gone(softc->disk, M_NOWAIT);
}
}
- if (error == ERESTART)
+ if (error == ERESTART) {
+ CAM_PROBE2(da, recovery, ccb, error);
return (ERESTART);
+ }
#ifdef CAM_IO_STATS
switch (ccb->ccb_h.status & CAM_STATUS_MASK) {
@@ -6351,7 +6359,9 @@
if (softc->quirks & DA_Q_RETRY_BUSY)
sense_flags |= SF_RETRY_BUSY;
- return(cam_periph_error(ccb, cam_flags, sense_flags));
+ error = cam_periph_error(ccb, cam_flags, sense_flags);
+ CAM_PROBE2(da, recovery, ccb, error);
+ return (error);
}
static void

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