Commit 6757ccc5 authored by Peter Beutner's avatar Peter Beutner Committed by Linus Torvalds

[PATCH] dvb: core: fix race condition in FE_READ_STATUS ioctl

Fix a race condition where an application which issued a FE_READ_STATUS ioctl
directly after FE_SET_FRONTEND would see an old status, i.e.  FE_READ_STATUS
would be executed before the frontend thread has even seen the tungin request
from FE_SET_FRONTEND.
Signed-off-by: default avatarPeter Beutner <p.beutner@gmx.net>
Signed-off-by: default avatarJohannes Stezenbach <js@linuxtv.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 25a26ec3
......@@ -626,11 +626,21 @@ static int dvb_frontend_ioctl(struct inode *inode, struct file *file,
break;
}
case FE_READ_STATUS:
case FE_READ_STATUS: {
fe_status_t* status = parg;
/* if retune was requested but hasn't occured yet, prevent
* that user get signal state from previous tuning */
if(fepriv->state == FESTATE_RETUNE) {
err=0;
*status = 0;
break;
}
if (fe->ops->read_status)
err = fe->ops->read_status(fe, (fe_status_t*) parg);
err = fe->ops->read_status(fe, status);
break;
}
case FE_READ_BER:
if (fe->ops->read_ber)
err = fe->ops->read_ber(fe, (__u32*) parg);
......
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