diff options
| author | Santosh Nayak <santoshprasadnayak@gmail.com> | 2012-02-26 19:05:03 +0530 |
|---|---|---|
| committer | James Bottomley <JBottomley@Parallels.com> | 2012-02-29 16:52:59 -0600 |
| commit | 50ec5babd3b9da274ac3e0d5ca0c4772e3c7bc8d (patch) | |
| tree | 8f975cfed3e6bd9b1e15dd862bf8f7ad9dd9387d | |
| parent | bdaefbf580cd200ae3230b6aacd1f4f2dadb18e3 (diff) | |
| download | linux-50ec5babd3b9da274ac3e0d5ca0c4772e3c7bc8d.tar.bz2 | |
[SCSI] pm8001: Fix possible racing condition.
There is a possble racing scenario.
'process_oq' is called by two routines, as shown below.
pm8001_8001_dispatch = {
.......
.isr = pm8001_chip_isr --> process_oq,// A
.isr_process_oq = process_oq, // B
.....
}
process_oq() --> process_one_iomb() --> mpi_sata_completion()
In 'mpi_sata_completion', "pm8001_ha->lock" is first released.
It means lock is taken before, which is true for
the context A, as 'pm8001_ha->lock' is taken in 'pm8001_chip_isr()'
But for context B there is no lock taken before and pm8001_ha->lock
is unlocked in 'mpi_sata_completion()'. This may unlock the lock
taken in context A. Possible racing ??
If 'pm8001_ha->lock' is taken in 'process_oq()' instead of
'pm8001_chip_isr' then the above issue can be avoided.
Signed-off-by: Santosh Nayak <santoshprasadnayak@gmail.com>
Acked-by: Jack Wang <jack_wang@usish.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
| -rw-r--r-- | drivers/scsi/pm8001/pm8001_hwi.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/scsi/pm8001/pm8001_hwi.c b/drivers/scsi/pm8001/pm8001_hwi.c index 871d1c3fa01b..dc28ae186450 100644 --- a/drivers/scsi/pm8001/pm8001_hwi.c +++ b/drivers/scsi/pm8001/pm8001_hwi.c @@ -3869,7 +3869,9 @@ static int process_oq(struct pm8001_hba_info *pm8001_ha) void *pMsg1 = NULL; u8 bc = 0; u32 ret = MPI_IO_STATUS_FAIL; + unsigned long flags; + spin_lock_irqsave(&pm8001_ha->lock, flags); circularQ = &pm8001_ha->outbnd_q_tbl[0]; do { ret = mpi_msg_consume(pm8001_ha, circularQ, &pMsg1, &bc); @@ -3890,6 +3892,7 @@ static int process_oq(struct pm8001_hba_info *pm8001_ha) break; } } while (1); + spin_unlock_irqrestore(&pm8001_ha->lock, flags); return ret; } @@ -4295,12 +4298,9 @@ static u32 pm8001_chip_is_our_interupt(struct pm8001_hba_info *pm8001_ha) static irqreturn_t pm8001_chip_isr(struct pm8001_hba_info *pm8001_ha) { - unsigned long flags; - spin_lock_irqsave(&pm8001_ha->lock, flags); pm8001_chip_interrupt_disable(pm8001_ha); process_oq(pm8001_ha); pm8001_chip_interrupt_enable(pm8001_ha); - spin_unlock_irqrestore(&pm8001_ha->lock, flags); return IRQ_HANDLED; } |