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powerpc/mpic_msgr: add lock for MPIC message global variable 

Also fix issue of accessing invalid msgr pointer issue. The local
msgr pointer in fucntion mpic_msgr_get will be accessed before
getting a valid address which will cause kernel crash.

Signed-off-by: Mingkai Hu <Mingkai.hu@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
This commit is contained in:
Mingkai Hu 2012-04-16 10:05:06 +08:00 committed by Kumar Gala
parent bdce27c7f7
commit e0a5a6c381
1 changed files with 5 additions and 5 deletions
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10
arch/powerpc/sysdev/mpic_msgr.c
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@ -27,6 +27,7 @@
static struct mpic_msgr **mpic_msgrs;
static unsigned int mpic_msgr_count;
static DEFINE_RAW_SPINLOCK(msgrs_lock);
static inline void _mpic_msgr_mer_write(struct mpic_msgr *msgr, u32 value)
{
@ -56,12 +57,11 @@ struct mpic_msgr *mpic_msgr_get(unsigned int reg_num)
if (reg_num >= mpic_msgr_count)
return ERR_PTR(-ENODEV);
raw_spin_lock_irqsave(&msgr->lock, flags);
if (mpic_msgrs[reg_num]->in_use == MSGR_FREE) {
msgr = mpic_msgrs[reg_num];
raw_spin_lock_irqsave(&msgrs_lock, flags);
msgr = mpic_msgrs[reg_num];
if (msgr->in_use == MSGR_FREE)
msgr->in_use = MSGR_INUSE;
}
raw_spin_unlock_irqrestore(&msgr->lock, flags);
raw_spin_unlock_irqrestore(&msgrs_lock, flags);
return msgr;
}