[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: 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>
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1 changed files with 14 additions and 4 deletions
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@ -626,11 +626,21 @@ static int dvb_frontend_ioctl(struct inode *inode, struct file *file,
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break;
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}
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case FE_READ_STATUS:
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if (fe->ops->read_status)
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err = fe->ops->read_status(fe, (fe_status_t*) parg);
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break;
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case FE_READ_STATUS: {
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fe_status_t* status = parg;
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/* if retune was requested but hasn't occured yet, prevent
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* that user get signal state from previous tuning */
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if(fepriv->state == FESTATE_RETUNE) {
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err=0;
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*status = 0;
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break;
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}
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if (fe->ops->read_status)
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err = fe->ops->read_status(fe, status);
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break;
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}
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case FE_READ_BER:
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if (fe->ops->read_ber)
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err = fe->ops->read_ber(fe, (__u32*) parg);
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