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Add locking for sscdisk(4) and mark it MPSAFE. Since this driver just

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makes calls out to the emulator, the locking is fairly simple.  A global
mutex protects the list of ssc disks, and each ssc disk has a mutex
to protect it's bioq.

Approved by:	marcel
This commit is contained in:
John Baldwin 2012-08-16 17:17:08 +00:00
parent 344aebe2c2
commit 9ea9af5281
1 changed files with 19 additions and 13 deletions
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32
sys/ia64/ia64/sscdisk.c
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@ -77,13 +77,15 @@ static MALLOC_DEFINE(M_SSC, "ssc_disk", "Simulator Disk");
static d_strategy_t sscstrategy;
static LIST_HEAD(, ssc_s) ssc_softc_list = LIST_HEAD_INITIALIZER(ssc_softc_list);
static struct mtx ssc_list_lock;
MTX_SYSINIT(ssc_list, &ssc_list_lock, "ssc list", MTX_DEF);
struct ssc_s {
int unit;
LIST_ENTRY(ssc_s) list;
struct bio_queue_head bio_queue;
struct disk *disk;
struct cdev *dev;
struct mtx lock;
int busy;
int fd;
};
@ -94,30 +96,27 @@ static void
sscstrategy(struct bio *bp)
{
struct ssc_s *sc;
int s;
struct disk_req req;
struct disk_stat stat;
u_long len, va, off;
sc = bp->bio_disk->d_drv1;
s = splbio();
mtx_lock(&sc->lock);
bioq_disksort(&sc->bio_queue, bp);
if (sc->busy) {
splx(s);
mtx_unlock(&sc->lock);
return;
}
sc->busy++;
while (1) {
for (;;) {
bp = bioq_takefirst(&sc->bio_queue);
splx(s);
if (!bp)
break;
mtx_unlock(&sc->lock);
va = (u_long) bp->bio_data;
len = bp->bio_bcount;
off = bp->bio_pblkno << DEV_BSHIFT;
@ -140,10 +139,11 @@ sscstrategy(struct bio *bp)
}
bp->bio_resid = 0;
biodone(bp);
s = splbio();
mtx_lock(&sc->lock);
}
sc->busy = 0;
mtx_unlock(&sc->lock);
return;
}
@ -158,17 +158,24 @@ ssccreate(int unit)
if (fd == -1)
return (NULL);
sc = malloc(sizeof(*sc), M_SSC, M_WAITOK | M_ZERO);
mtx_lock(&ssc_list_lock);
if (unit == -1)
unit = sscunits++;
/* Make sure this unit isn't already in action */
LIST_FOREACH(sc, &ssc_softc_list, list) {
if (sc->unit == unit)
if (sc->unit == unit) {
mtx_unlock(&ssc_list_lock);
free(sc, M_SSC);
return (NULL);
}
}
sc = malloc(sizeof(*sc), M_SSC, M_WAITOK | M_ZERO);
LIST_INSERT_HEAD(&ssc_softc_list, sc, list);
sc->unit = unit;
mtx_unlock(&ssc_list_lock);
bioq_init(&sc->bio_queue);
mtx_init(&sc->lock, "ssc", NULL, MTX_DEF);
sc->disk = disk_alloc();
sc->disk->d_drv1 = sc;
@ -180,7 +187,6 @@ ssccreate(int unit)
sc->disk->d_sectorsize = DEV_BSIZE;
sc->disk->d_strategy = sscstrategy;
sc->disk->d_unit = sc->unit;
sc->disk->d_flags = DISKFLAG_NEEDSGIANT;
disk_create(sc->disk, DISK_VERSION);
sc->fd = fd;
if (sc->unit == 0)