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dmaengine: idxd: use spin_lock_irqsave before wait_event_lock_irq
In idxd_cmd_exec(), wait_event_lock_irq() explicitly calls
spin_unlock_irq()/spin_lock_irq(). If the interrupt is on before entering
wait_event_lock_irq(), it will become off status after
wait_event_lock_irq() is called. Later, wait_for_completion() may go to
sleep but irq is disabled. The scenario is warned in might_sleep().
Fix it by using spin_lock_irqsave() instead of the primitive spin_lock()
to save the irq status before entering wait_event_lock_irq() and using
spin_unlock_irqrestore() instead of the primitive spin_unlock() to restore
the irq status before entering wait_for_completion().
Before the change:
idxd_cmd_exec() {
interrupt is on
spin_lock() // interrupt is on
wait_event_lock_irq()
spin_unlock_irq() // interrupt is enabled
...
spin_lock_irq() // interrupt is disabled
spin_unlock() // interrupt is still disabled
wait_for_completion() // report "BUG: sleeping function
// called from invalid context...
// in_atomic() irqs_disabled()"
}
After applying spin_lock_irqsave():
idxd_cmd_exec() {
interrupt is on
spin_lock_irqsave() // save the on state
// interrupt is disabled
wait_event_lock_irq()
spin_unlock_irq() // interrupt is enabled
...
spin_lock_irq() // interrupt is disabled
spin_unlock_irqrestore() // interrupt is restored to on
wait_for_completion() // No Call trace
}
Fixes: f9f4082dbc
("dmaengine: idxd: remove interrupt disable for cmd_lock")
Signed-off-by: Rex Zhang <rex.zhang@intel.com>
Signed-off-by: Lijun Pan <lijun.pan@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Fenghua Yu <fenghua.yu@intel.com>
Link: https://lore.kernel.org/r/20230916060619.3744220-1-rex.zhang@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
parent
3f4b82167a
commit
c0409dd3d1
1 changed files with 3 additions and 2 deletions
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@ -477,6 +477,7 @@ static void idxd_cmd_exec(struct idxd_device *idxd, int cmd_code, u32 operand,
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union idxd_command_reg cmd;
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DECLARE_COMPLETION_ONSTACK(done);
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u32 stat;
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unsigned long flags;
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if (idxd_device_is_halted(idxd)) {
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dev_warn(&idxd->pdev->dev, "Device is HALTED!\n");
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@ -490,7 +491,7 @@ static void idxd_cmd_exec(struct idxd_device *idxd, int cmd_code, u32 operand,
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cmd.operand = operand;
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cmd.int_req = 1;
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spin_lock(&idxd->cmd_lock);
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spin_lock_irqsave(&idxd->cmd_lock, flags);
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wait_event_lock_irq(idxd->cmd_waitq,
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!test_bit(IDXD_FLAG_CMD_RUNNING, &idxd->flags),
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idxd->cmd_lock);
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@ -507,7 +508,7 @@ static void idxd_cmd_exec(struct idxd_device *idxd, int cmd_code, u32 operand,
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* After command submitted, release lock and go to sleep until
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* the command completes via interrupt.
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*/
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spin_unlock(&idxd->cmd_lock);
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spin_unlock_irqrestore(&idxd->cmd_lock, flags);
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wait_for_completion(&done);
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stat = ioread32(idxd->reg_base + IDXD_CMDSTS_OFFSET);
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spin_lock(&idxd->cmd_lock);
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