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1) Add non-blocking I/O on read

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2) Add checks to make sure we do not dereference the softc when not found
because the device has been removed.
This commit is contained in:
Nick Hibma 1999-06-13 20:49:12 +00:00
parent 680514601e
commit 7b69218647
1 changed files with 32 additions and 6 deletions
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38
sys/dev/usb/ums.c
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@ -397,6 +397,7 @@ ums_detach(device_t self)
* the time the process gets a chance to notice. *_close and friends
* should be fixed to handle this case.
* Or we should do a delayed detach for this.
* Does this delay now force tsleep to exit with an error?
*/
#if 0
@ -627,7 +628,7 @@ ums_close(dev_t dev, int flag, int fmt, struct proc *p)
{
USB_GET_SC(ums, UMSUNIT(dev), sc);
if (sc == NULL)
if (!sc)
return 0;
if (sc->sc_enabled)
@ -646,14 +647,18 @@ ums_read(dev_t dev, struct uio *uio, int flag)
int error;
s = splusb();
if (!sc) {
splx(s);
return EIO;
}
while (sc->qcount == 0 ) {
/* NWH XXX non blocking I/O ??
if (non blocking I/O ) {
if (flag & IO_NDELAY) { /* non-blocking I/O */
splx(s);
return EWOULDBLOCK;
} else {
*/
sc->state |= UMS_ASLEEP;
}
sc->state |= UMS_ASLEEP; /* blocking I/O */
error = tsleep(sc, PZERO | PCATCH, "umsrea", 0);
if (error) {
splx(s);
@ -662,8 +667,23 @@ ums_read(dev_t dev, struct uio *uio, int flag)
splx(s);
return EINTR;
}
#if defined(__FreeBSD__)
/* check whether the device is still there */
sc = devclass_get_softc(ums_devclass, UMSUNIT(dev));
if (!sc) {
splx(s);
return EIO;
}
#endif
}
/*
* XXX we could optimise the use of splx/splusb somewhat. The writer
* process only extends qcount and qtail. We could copy them and use the copies
* to do the copying out of the queue.
*/
while ((sc->qcount > 0) && (uio->uio_resid > 0)) {
l = (sc->qcount < uio->uio_resid? sc->qcount:uio->uio_resid);
if (l > sizeof(buf))
@ -694,6 +714,9 @@ ums_poll(dev_t dev, int events, struct proc *p)
int revents = 0;
int s;
if (!sc)
return 0;
s = splusb();
if (events & (POLLIN | POLLRDNORM)) {
if (sc->qcount) {
@ -716,6 +739,9 @@ ums_ioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct proc *p)
int s;
mousemode_t mode;
if (!sc)
return EIO;
switch(cmd) {
case MOUSE_GETHWINFO:
*(mousehw_t *)addr = sc->hw;