Track Ref / DeRef and Hold / Unhold that da is doing to track down
leaks. We assume each source can be taken / dropped only once and don't recurse. These are only enabled via DA_TRACK_REFS or INVARIANTS. There appreas to be a reference leak under extreme load, and these should help us colaberatively work it out. It also documents better the reference / holding protocol better. Reviewed by: ken@, scottl@ Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D14040
This commit is contained in:
parent
de64cba2c7
commit
d047fd281d
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=328415
@ -34,6 +34,7 @@ __FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#ifdef _KERNEL
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#include "opt_da.h"
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/bio.h>
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@ -51,6 +52,7 @@ __FBSDID("$FreeBSD$");
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#include <sys/sbuf.h>
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#include <geom/geom.h>
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#include <geom/geom_disk.h>
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#include <machine/atomic.h>
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#endif /* _KERNEL */
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#ifndef _KERNEL
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@ -291,6 +293,18 @@ struct disk_params {
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#define DA_WORK_TUR (1 << 16)
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typedef enum {
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DA_REF_OPEN = 1,
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DA_REF_OPEN_HOLD,
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DA_REF_CLOSE_HOLD,
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DA_REF_PROBE_HOLD,
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DA_REF_TUR,
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DA_REF_GEOM,
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DA_REF_SYSCTL,
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DA_REF_REPROBE,
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DA_REF_MAX /* KEEP LAST */
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} da_ref_token;
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struct da_softc {
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struct cam_iosched_softc *cam_iosched;
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struct bio_queue_head delete_run_queue;
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@ -335,6 +349,7 @@ struct da_softc {
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uint8_t unmap_buf[UNMAP_BUF_SIZE];
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struct scsi_read_capacity_data_long rcaplong;
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struct callout mediapoll_c;
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int ref_flags[DA_REF_MAX];
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#ifdef CAM_IO_STATS
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struct sysctl_ctx_list sysctl_stats_ctx;
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struct sysctl_oid *sysctl_stats_tree;
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@ -1469,6 +1484,143 @@ PERIPHDRIVER_DECLARE(da, dadriver);
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static MALLOC_DEFINE(M_SCSIDA, "scsi_da", "scsi_da buffers");
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/*
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* This driver takes out references / holds in well defined pairs, never
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* recursively. These macros / inline functions enforce those rules. They
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* are only enabled with DA_TRACK_REFS or INVARIANTS. If DA_TRACK_REFS is
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* defined to be 2 or larger, the tracking also includes debug printfs.
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*/
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#if defined(DA_TRACK_REFS) || defined(INVARIANTS)
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#ifndef DA_TRACK_REFS
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#define DA_TRACK_REFS 1
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#endif
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#if DA_TRACK_REFS > 1
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#define CAM_PERIPH_PRINT(p, msg, args...) \
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printf("%s%d:" msg, (periph)->periph_name, (periph)->unit_number, ##args)
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static const char *da_ref_text[] = {
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"bogus",
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"open",
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"open hold",
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"close hold",
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"reprobe hold",
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"Test Unit Ready",
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"Geom",
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"sysctl",
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"reprobe",
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"max -- also bogus"
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};
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#else
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#define CAM_PERIPH_PRINT(p, msg, args...)
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#endif
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static inline void
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token_sanity(da_ref_token token)
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{
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if ((unsigned)token >= DA_REF_MAX)
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panic("Bad token value passed in %d\n", token);
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}
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static inline int
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da_periph_hold(struct cam_periph *periph, int priority, da_ref_token token)
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{
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int err = cam_periph_hold(periph, priority);
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token_sanity(token);
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CAM_PERIPH_PRINT(periph, "Holding device %s (%d): %d\n",
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da_ref_text[token], token, err);
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if (err == 0) {
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int cnt;
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struct da_softc *softc = periph->softc;
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cnt = atomic_fetchadd_int(&softc->ref_flags[token], 1);
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if (cnt != 0)
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panic("Re-holding for reason %d, cnt = %d", token, cnt);
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}
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return (err);
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}
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static inline void
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da_periph_unhold(struct cam_periph *periph, da_ref_token token)
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{
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int cnt;
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struct da_softc *softc = periph->softc;
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token_sanity(token);
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cam_periph_unhold(periph);
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CAM_PERIPH_PRINT(periph, "Unholding device %s (%d)\n",
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da_ref_text[token], token);
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cnt = atomic_fetchadd_int(&softc->ref_flags[token], -1);
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if (cnt != 1)
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panic("Unholding %d with cnt = %d", token, cnt);
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}
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static inline int
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da_periph_acquire(struct cam_periph *periph, da_ref_token token)
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{
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int err = cam_periph_acquire(periph);
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token_sanity(token);
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CAM_PERIPH_PRINT(periph, "acquiring device %s (%d): %d\n",
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da_ref_text[token], token, err);
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if (err == CAM_REQ_CMP) {
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int cnt;
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struct da_softc *softc = periph->softc;
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cnt = atomic_fetchadd_int(&softc->ref_flags[token], 1);
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if (cnt != 0)
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panic("Re-refing for reason %d, cnt = %d", token, cnt);
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}
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return (err);
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}
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static inline void
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da_periph_release(struct cam_periph *periph, da_ref_token token)
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{
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int cnt;
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struct da_softc *softc = periph->softc;
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token_sanity(token);
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cam_periph_release(periph);
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CAM_PERIPH_PRINT(periph, "releasing device %s (%d)\n",
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da_ref_text[token], token);
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cnt = atomic_fetchadd_int(&softc->ref_flags[token], -1);
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if (cnt != 1)
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panic("Unholding %d with cnt = %d", token, cnt);
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}
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static inline void
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da_periph_release_locked(struct cam_periph *periph, da_ref_token token)
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{
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int cnt;
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struct da_softc *softc = periph->softc;
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token_sanity(token);
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cam_periph_release_locked(periph);
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CAM_PERIPH_PRINT(periph, "releasing device (locked) %s (%d)\n",
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da_ref_text[token], token);
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cnt = atomic_fetchadd_int(&softc->ref_flags[token], -1);
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if (cnt != 1)
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panic("Unholding %d with cnt = %d", token, cnt);
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}
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#define cam_periph_hold POISON
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#define cam_periph_unhold POISON
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#define cam_periph_acquire POISON
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#define cam_periph_release POISON
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#define cam_periph_release_locked POISON
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#else
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#define da_periph_hold(periph, prio, token) cam_periph_hold((periph), (prio))
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#define da_periph_unhold(periph, token) cam_periph_unhold((periph))
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#define da_periph_acquire(periph, token) cam_periph_acquire((periph))
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#define da_periph_release(periph, token) cam_periph_release((periph))
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#define da_periph_release_locked(periph, token) cam_periph_release_locked((periph))
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#endif
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static int
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daopen(struct disk *dp)
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{
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@ -1477,14 +1629,14 @@ daopen(struct disk *dp)
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int error;
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periph = (struct cam_periph *)dp->d_drv1;
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if (cam_periph_acquire(periph) != CAM_REQ_CMP) {
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if (da_periph_acquire(periph, DA_REF_OPEN) != CAM_REQ_CMP) {
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return (ENXIO);
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}
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cam_periph_lock(periph);
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if ((error = cam_periph_hold(periph, PRIBIO|PCATCH)) != 0) {
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if ((error = da_periph_hold(periph, PRIBIO|PCATCH, DA_REF_OPEN_HOLD)) != 0) {
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cam_periph_unlock(periph);
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cam_periph_release(periph);
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da_periph_release(periph, DA_REF_OPEN);
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return (error);
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}
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@ -1512,11 +1664,11 @@ daopen(struct disk *dp)
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softc->flags |= DA_FLAG_OPEN;
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}
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cam_periph_unhold(periph);
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da_periph_unhold(periph, DA_REF_OPEN_HOLD);
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cam_periph_unlock(periph);
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if (error != 0)
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cam_periph_release(periph);
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da_periph_release(periph, DA_REF_OPEN);
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return (error);
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}
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@ -1534,7 +1686,7 @@ daclose(struct disk *dp)
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CAM_DEBUG(periph->path, CAM_DEBUG_TRACE | CAM_DEBUG_PERIPH,
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("daclose\n"));
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if (cam_periph_hold(periph, PRIBIO) == 0) {
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if (da_periph_hold(periph, PRIBIO, DA_REF_CLOSE_HOLD) == 0) {
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/* Flush disk cache. */
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if ((softc->flags & DA_FLAG_DIRTY) != 0 &&
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@ -1557,7 +1709,7 @@ daclose(struct disk *dp)
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(softc->quirks & DA_Q_NO_PREVENT) == 0)
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daprevent(periph, PR_ALLOW);
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cam_periph_unhold(periph);
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da_periph_unhold(periph, DA_REF_CLOSE_HOLD);
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}
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/*
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@ -1572,7 +1724,7 @@ daclose(struct disk *dp)
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while (softc->refcount != 0)
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cam_periph_sleep(periph, &softc->refcount, PRIBIO, "daclose", 1);
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cam_periph_unlock(periph);
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cam_periph_release(periph);
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da_periph_release(periph, DA_REF_OPEN);
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return (0);
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}
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@ -1750,7 +1902,7 @@ dadiskgonecb(struct disk *dp)
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struct cam_periph *periph;
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periph = (struct cam_periph *)dp->d_drv1;
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cam_periph_release(periph);
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da_periph_release(periph, DA_REF_GEOM);
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}
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static void
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@ -1910,7 +2062,7 @@ daasync(void *callback_arg, u_int32_t code,
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case AC_SCSI_AEN:
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softc = (struct da_softc *)periph->softc;
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if (!cam_iosched_has_work_flags(softc->cam_iosched, DA_WORK_TUR)) {
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if (cam_periph_acquire(periph) == CAM_REQ_CMP) {
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if (da_periph_acquire(periph, DA_REF_TUR) == CAM_REQ_CMP) {
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cam_iosched_set_work_flags(softc->cam_iosched, DA_WORK_TUR);
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daschedule(periph);
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}
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@ -1955,7 +2107,7 @@ dasysctlinit(void *context, int pending)
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* periph was held for us when this task was enqueued
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*/
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if (periph->flags & CAM_PERIPH_INVALID) {
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cam_periph_release(periph);
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da_periph_release(periph, DA_REF_SYSCTL);
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return;
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}
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@ -1970,7 +2122,7 @@ dasysctlinit(void *context, int pending)
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CTLFLAG_RD, 0, tmpstr, "device_index");
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if (softc->sysctl_tree == NULL) {
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printf("dasysctlinit: unable to allocate sysctl tree\n");
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cam_periph_release(periph);
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da_periph_release(periph, DA_REF_SYSCTL);
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return;
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}
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@ -2052,7 +2204,7 @@ dasysctlinit(void *context, int pending)
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xpt_action((union ccb *)&cts);
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cam_periph_unlock(periph);
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if (cts.ccb_h.status != CAM_REQ_CMP) {
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cam_periph_release(periph);
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da_periph_release(periph, DA_REF_SYSCTL);
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return;
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}
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if (cts.protocol == PROTO_SCSI && cts.transport == XPORT_FC) {
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@ -2103,7 +2255,7 @@ dasysctlinit(void *context, int pending)
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cam_iosched_sysctl_init(softc->cam_iosched, &softc->sysctl_ctx,
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softc->sysctl_tree);
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cam_periph_release(periph);
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da_periph_release(periph, DA_REF_SYSCTL);
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}
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static int
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@ -2269,9 +2421,9 @@ daprobedone(struct cam_periph *periph, union ccb *ccb)
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wakeup(&softc->disk->d_mediasize);
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if ((softc->flags & DA_FLAG_ANNOUNCED) == 0) {
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softc->flags |= DA_FLAG_ANNOUNCED;
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cam_periph_unhold(periph);
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da_periph_unhold(periph, DA_REF_PROBE_HOLD);
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} else
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cam_periph_release_locked(periph);
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da_periph_release_locked(periph, DA_REF_REPROBE);
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}
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static void
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@ -2484,8 +2636,10 @@ daregister(struct cam_periph *periph, void *arg)
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* Take an exclusive refcount on the periph while dastart is called
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* to finish the probe. The reference will be dropped in dadone at
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* the end of probe.
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*
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* XXX if cam_periph_hold returns an error, we don't hold a refcount.
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*/
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(void)cam_periph_hold(periph, PRIBIO);
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(void)da_periph_hold(periph, PRIBIO, DA_REF_PROBE_HOLD);
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/*
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* Schedule a periodic event to occasionally send an
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@ -2579,7 +2733,7 @@ daregister(struct cam_periph *periph, void *arg)
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* We'll release this reference once GEOM calls us back (via
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* dadiskgonecb()) telling us that our provider has been freed.
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*/
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if (cam_periph_acquire(periph) != CAM_REQ_CMP) {
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if (da_periph_acquire(periph, DA_REF_GEOM) != CAM_REQ_CMP) {
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xpt_print(periph->path, "%s: lost periph during "
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"registration!\n", __func__);
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cam_periph_lock(periph);
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@ -2965,7 +3119,7 @@ dastart(struct cam_periph *periph, union ccb *start_ccb)
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if (cam_iosched_has_work_flags(softc->cam_iosched, DA_WORK_TUR)) {
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cam_iosched_clr_work_flags(softc->cam_iosched, DA_WORK_TUR);
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cam_periph_release_locked(periph);
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da_periph_release_locked(periph, DA_REF_TUR);
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}
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if ((bp->bio_flags & BIO_ORDERED) != 0 ||
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@ -4547,7 +4701,7 @@ dadone(struct cam_periph *periph, union ccb *done_ccb)
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* we have successfully attached.
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*/
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/* increase the refcount */
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if (cam_periph_acquire(periph) == CAM_REQ_CMP) {
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if (da_periph_acquire(periph, DA_REF_SYSCTL) == CAM_REQ_CMP) {
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taskqueue_enqueue(taskqueue_thread,
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&softc->sysctl_task);
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@ -5392,7 +5546,7 @@ dadone(struct cam_periph *periph, union ccb *done_ccb)
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/*getcount_only*/0);
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}
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xpt_release_ccb(done_ccb);
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cam_periph_release_locked(periph);
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da_periph_release_locked(periph, DA_REF_TUR);
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return;
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}
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default:
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@ -5413,7 +5567,7 @@ dareprobe(struct cam_periph *periph)
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if (softc->state != DA_STATE_NORMAL)
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return;
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status = cam_periph_acquire(periph);
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status = da_periph_acquire(periph, DA_REF_REPROBE);
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KASSERT(status == CAM_REQ_CMP,
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("dareprobe: cam_periph_acquire failed"));
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@ -5513,7 +5667,7 @@ damediapoll(void *arg)
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if (!cam_iosched_has_work_flags(softc->cam_iosched, DA_WORK_TUR) &&
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LIST_EMPTY(&softc->pending_ccbs)) {
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if (cam_periph_acquire(periph) == CAM_REQ_CMP) {
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if (da_periph_acquire(periph, DA_REF_TUR) == CAM_REQ_CMP) {
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cam_iosched_set_work_flags(softc->cam_iosched, DA_WORK_TUR);
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daschedule(periph);
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}
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@ -345,6 +345,9 @@ ATA_STATIC_ID opt_ada.h
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CHANGER_MIN_BUSY_SECONDS opt_cd.h
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CHANGER_MAX_BUSY_SECONDS opt_cd.h
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# Options used only in cam/scsi/scsi_da.c
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DA_TRACK_REFS opt_da.h
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# Options used only in cam/scsi/scsi_sa.c.
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SA_IO_TIMEOUT opt_sa.h
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SA_SPACE_TIMEOUT opt_sa.h
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