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authorRex Zhang <rex.zhang@intel.com>2023-09-16 09:06:19 +0300
committerVinod Koul <vkoul@kernel.org>2023-10-04 10:31:29 +0300
commitc0409dd3d151f661e7e57b901a81a02565df163c (patch)
tree34bcd9303a657dd2edef2bfab194bc113282f036 /drivers/dma
parent3f4b82167a3b1f4ddb33d890f758a042ef4ceef1 (diff)
downloadlinux-c0409dd3d151f661e7e57b901a81a02565df163c.tar.xz
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: f9f4082dbc56 ("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>
Diffstat (limited to 'drivers/dma')
-rw-r--r--drivers/dma/idxd/device.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index 22d6f4e455b7..8f754f922217 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -477,6 +477,7 @@ static void idxd_cmd_exec(struct idxd_device *idxd, int cmd_code, u32 operand,
union idxd_command_reg cmd;
DECLARE_COMPLETION_ONSTACK(done);
u32 stat;
+ unsigned long flags;
if (idxd_device_is_halted(idxd)) {
dev_warn(&idxd->pdev->dev, "Device is HALTED!\n");
@@ -490,7 +491,7 @@ static void idxd_cmd_exec(struct idxd_device *idxd, int cmd_code, u32 operand,
cmd.operand = operand;
cmd.int_req = 1;
- spin_lock(&idxd->cmd_lock);
+ spin_lock_irqsave(&idxd->cmd_lock, flags);
wait_event_lock_irq(idxd->cmd_waitq,
!test_bit(IDXD_FLAG_CMD_RUNNING, &idxd->flags),
idxd->cmd_lock);
@@ -507,7 +508,7 @@ static void idxd_cmd_exec(struct idxd_device *idxd, int cmd_code, u32 operand,
* After command submitted, release lock and go to sleep until
* the command completes via interrupt.
*/
- spin_unlock(&idxd->cmd_lock);
+ spin_unlock_irqrestore(&idxd->cmd_lock, flags);
wait_for_completion(&done);
stat = ioread32(idxd->reg_base + IDXD_CMDSTS_OFFSET);
spin_lock(&idxd->cmd_lock);