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fd: Move from using device_busy to a refcount

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Use refcounting to delay the detach rather than device_busy and/or
device_unbusy. fd/fdc is one of the few consumers of device_busy in the
tree for that, and it's not a good fit. Also, nothing is waking 'fd' and
other drivers don't loop like this. Return EBUSY if we still have active
users.

Sponsored by:		Netflix
Reviewed by:		mav
Differential Revision:	https://reviews.freebsd.org/D31830
This commit is contained in:
Warner Losh 2021-09-29 20:18:28 -06:00
parent 8ea95b2fba
commit e2c1243f42
1 changed files with 23 additions and 11 deletions
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34
sys/dev/fdc/fdc.c
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@ -261,6 +261,7 @@ struct fd_data {
struct g_provider *fd_provider;
device_t dev;
struct bio_queue_head fd_bq;
bool gone;
};
#define FD_NOT_VALID -2
@ -1398,6 +1399,7 @@ fdautoselect(struct fd_data *fd)
static g_access_t fd_access;
static g_start_t fd_start;
static g_ioctl_t fd_ioctl;
static g_provgone_t fd_providergone;
struct g_class g_fd_class = {
.name = "FD",
@ -1405,6 +1407,7 @@ struct g_class g_fd_class = {
.start = fd_start,
.access = fd_access,
.ioctl = fd_ioctl,
.providergone = fd_providergone,
};
static int
@ -1413,7 +1416,6 @@ fd_access(struct g_provider *pp, int r, int w, int e)
struct fd_data *fd;
struct fdc_data *fdc;
int ar, aw, ae;
int busy;
fd = pp->geom->softc;
fdc = fd->fdc;
@ -1431,11 +1433,9 @@ fd_access(struct g_provider *pp, int r, int w, int e)
if (ar == 0 && aw == 0 && ae == 0) {
fd->options &= ~(FDOPT_NORETRY | FDOPT_NOERRLOG | FDOPT_NOERROR);
device_unbusy(fd->dev);
return (0);
}
busy = 0;
if (pp->acr == 0 && pp->acw == 0 && pp->ace == 0) {
if (fdmisccmd(fd, BIO_PROBE, NULL))
return (ENXIO);
@ -1453,13 +1453,9 @@ fd_access(struct g_provider *pp, int r, int w, int e)
fd->flags &= ~FD_NEWDISK;
mtx_unlock(&fdc->fdc_mtx);
}
device_busy(fd->dev);
busy = 1;
}
if (w > 0 && (fd->flags & FD_WP)) {
if (busy)
device_unbusy(fd->dev);
return (EROFS);
}
@ -1588,8 +1584,6 @@ fd_ioctl(struct g_provider *pp, u_long cmd, void *data, int fflag, struct thread
return (error);
};
/*
* Configuration/initialization stuff, per controller.
*/
@ -2055,6 +2049,16 @@ fd_attach(device_t dev)
return (0);
}
static void
fd_providergone(struct g_provider *pp)
{
struct fd_data *fd;
fd = pp->geom->softc;
fd->gone = true;
wakeup(fd);
}
static void
fd_detach_geom(void *arg, int flag)
{
@ -2070,9 +2074,17 @@ fd_detach(device_t dev)
struct fd_data *fd;
fd = device_get_softc(dev);
g_waitfor_event(fd_detach_geom, fd, M_WAITOK, NULL);
while (device_get_state(dev) == DS_BUSY)
tsleep(fd, PZERO, "fdd", hz/10);
while (!fd->gone) {
tsleep(fd, PZERO, "fdgone", hz/10);
}
/*
* There may be accesses to the floppy while we're waitng, so drain the
* motor callback here. fdc_detach turns off motor if it's still on when
* we get to this point.
*/
callout_drain(&fd->toffhandle);
return (0);