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Avoid race conditions related with registration and unregistration hba's.

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git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@179 d57e44dd-8a1f-0410-8b47-8ef2f437770f
This commit is contained in:
Stanislaw Gruszka
2007-08-31 13:01:22 +00:00
parent 59cfad3952
commit d31e5941e7
1 changed files with 50 additions and 28 deletions
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qla_isp/linux/isp_scst.c
+50 -28
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@@ -155,7 +155,7 @@ struct initiator {
ini_t * ini_next;
bus_t * ini_bus; /* backpointer to containing bus */
uint64_t ini_iid; /* initiator identifier */
struct scst_session * ini_scst_sess; /* FIXME: comment me */
struct scst_session * ini_scst_sess; /* sesson established by this remote initiator */
#ifdef NO_AUTOSENSE
/*
* There are cases when Autosense not work for some reason, at least for 24xx chipsets.
@@ -186,7 +186,9 @@ struct bus {
hba_register_t h; /* must be first */
ini_t * list[HASH_WIDTH]; /* hash list of known initiators */
struct scst_tgt * scst_tgt;
hba_register_t * unreg_hp; /* help to synchronize low level and SCST unregistration */
int enable; /* is target mode enabled in low level driver */
int need_reg; /* before SCST registration */
#ifdef NO_AUTOSENSE
int no_autosense; /* autosense not work for this hba */
#endif
@@ -662,11 +664,11 @@ scsi_target_start_cmd(tmd_cmd_t *tmd, int from_intr)
*/
spin_lock_irqsave(&scsi_target_lock, flags);
bp = bus_from_tmd(tmd);
if (bp == NULL) {
if (bp == NULL || bp->scst_tgt == NULL) {
spin_unlock_irqrestore(&scsi_target_lock, flags);
Eprintk("cannot find bus for incoming command\n");
Eprintk("cannot find %s for incoming command\n", (bp == NULL) ? "bus" : "SCST target");
return;
}
}
tmd->cd_bus = bp;
/*
@@ -870,6 +872,7 @@ scsi_target_handler(qact_e action, void *arg)
bp->no_autosense = 1;
}
#endif
bp->need_reg = 1;
spin_unlock_irqrestore(&scsi_target_lock, flags);
schedule_register_scst();
Iprintk("registering %s%d\n", hp->r_name, hp->r_inst);
@@ -974,10 +977,9 @@ scsi_target_handler(qact_e action, void *arg)
break;
}
memset(&bp->h, 0, sizeof (hba_register_t));
bp->unreg_hp = hp;
spin_unlock_irqrestore(&scsi_target_lock, flags);
schedule_unregister_scst();
Iprintk("unregistering %s%d\n", hp->r_name, hp->r_inst);
(hp->r_action)(QIN_HBA_UNREG, arg);
break;
}
default:
@@ -1280,19 +1282,22 @@ register_scst(void)
bus_t *bp;
int ntgts = 0;
// FIXME: race conditions
for (bp = busses; bp < &busses[MAX_BUS]; bp++) {
char name[32];
if (bp->h.r_action == NULL || bp->scst_tgt) {
spin_lock_irq(&scsi_target_lock);
if (bp->h.r_action == NULL || !bp->need_reg) {
spin_unlock_irq(&scsi_target_lock);
continue;
}
bp->need_reg = 0;
spin_unlock_irq(&scsi_target_lock);
// FIXME: give scst WWN or something like that
snprintf(name, sizeof(name), "%s%d", bp->h.r_name, bp->h.r_inst);
//bp->scst_tgt = scst_register(&isp_tgt_template);
// FIXME: we curently can not pass error to low level driver by tpublic interface
// FIXME: we reject tmd's when scst_tgt is NULL
bp->scst_tgt = scst_register(&isp_tgt_template, name);
if (bp->scst_tgt) {
SDprintk("%s: device %s\n", __FUNCTION__ ,name);
@@ -1312,25 +1317,42 @@ unregister_scst(void)
bus_t *bp;
for (bp = busses; bp < &busses[MAX_BUS]; bp++) {
if (bp->h.r_action == NULL && bp->scst_tgt) {
int i;
/* remove existing initiators */
for (i = 0; i < HASH_WIDTH; i++) {
ini_t *ini_next;
ini_t *ptr = bp->list[i];
if (ptr) {
do {
ini_next = ptr->ini_next;
free_ini(ptr);
} while ((ptr = ini_next) != NULL);
}
bp->list[i] = NULL;
}
int i;
struct scst_tgt *scst_tgt;
ini_t *list[HASH_WIDTH];
hba_register_t *unreg_hp;
spin_lock_irq(&scsi_target_lock);
if (bp->h.r_action != NULL || bp->unreg_hp == NULL) {
spin_unlock_irq(&scsi_target_lock);
continue;
scst_unregister(bp->scst_tgt);
memset(bp, 0, sizeof(bus_t));
}
/* make bp ready for next registration */
scst_tgt = bp->scst_tgt;
memcpy(list, bp->list, sizeof(bp->list));
unreg_hp = bp->unreg_hp;
memset(bp, 0, sizeof(bus_t));
spin_unlock_irq(&scsi_target_lock);
/* remove existing initiators */
for (i = 0; i < HASH_WIDTH; i++) {
ini_t *ini_next;
ini_t *ptr = list[i];
if (ptr) {
do {
ini_next = ptr->ini_next;
free_ini(ptr);
} while ((ptr = ini_next) != NULL);
}
bp->list[i] = NULL;
}
if (scst_tgt)
scst_unregister(scst_tgt);
/* now no one will call low level functions */
Iprintk("unregistering %s%d\n", unreg_hp->r_name, unreg_hp->r_inst);
(unreg_hp->r_action)(QIN_HBA_UNREG, unreg_hp);
}
}