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

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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: Peter Beutner <p.beutner@gmx.net>
Signed-off-by: Johannes Stezenbach <js@linuxtv.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Peter Beutner
2005-07-07 17:57:36 -07:00
committed by Linus Torvalds
parent 25a26ec3b6
commit 6757ccc57d
1 changed files with 14 additions and 4 deletions
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18
drivers/media/dvb/dvb-core/dvb_frontend.c
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@@ -626,11 +626,21 @@ static int dvb_frontend_ioctl(struct inode *inode, struct file *file,
break; break;
} }
case FE_READ_STATUS: case FE_READ_STATUS: {
if (fe->ops->read_status) fe_status_t* status = parg;
err = fe->ops->read_status(fe, (fe_status_t*) parg);
break;
/* 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, status);
break;
}
case FE_READ_BER: case FE_READ_BER:
if (fe->ops->read_ber) if (fe->ops->read_ber)
err = fe->ops->read_ber(fe, (__u32*) parg); err = fe->ops->read_ber(fe, (__u32*) parg);