* [PATCH] PCI: Remove WARN_ON(in_interrupt()).
@ 2021-02-08 19:44 Sebastian Andrzej Siewior
2021-02-10 23:01 ` Bjorn Helgaas
0 siblings, 1 reply; 2+ messages in thread
From: Sebastian Andrzej Siewior @ 2021-02-08 19:44 UTC (permalink / raw)
To: linux-pci; +Cc: Bjorn Helgaas, Thomas Gleixner, Sebastian Andrzej Siewior
WARN_ON(in_interrupt()) is used for historic reasons to ensure proper
usage of down_read() and predates might_sleep() and lockdep.
down_read() has might_sleep() which also catches users from preemption
disabled regions while in_interrupt() does not.
Remove WARN_ON(in_interrupt()) because there is better debugging
facility.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
drivers/pci/search.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/drivers/pci/search.c b/drivers/pci/search.c
index 2061672954ee3..b4c138a6ec025 100644
--- a/drivers/pci/search.c
+++ b/drivers/pci/search.c
@@ -168,7 +168,6 @@ struct pci_bus *pci_find_next_bus(const struct pci_bus *from)
struct list_head *n;
struct pci_bus *b = NULL;
- WARN_ON(in_interrupt());
down_read(&pci_bus_sem);
n = from ? from->node.next : pci_root_buses.next;
if (n != &pci_root_buses)
@@ -196,7 +195,6 @@ struct pci_dev *pci_get_slot(struct pci_bus *bus, unsigned int devfn)
{
struct pci_dev *dev;
- WARN_ON(in_interrupt());
down_read(&pci_bus_sem);
list_for_each_entry(dev, &bus->devices, bus_list) {
@@ -274,7 +272,6 @@ static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id,
struct device *dev_start = NULL;
struct pci_dev *pdev = NULL;
- WARN_ON(in_interrupt());
if (from)
dev_start = &from->dev;
dev = bus_find_device(&pci_bus_type, dev_start, (void *)id,
@@ -381,7 +378,6 @@ int pci_dev_present(const struct pci_device_id *ids)
{
struct pci_dev *found = NULL;
- WARN_ON(in_interrupt());
while (ids->vendor || ids->subvendor || ids->class_mask) {
found = pci_get_dev_by_id(ids, NULL);
if (found) {
--
2.30.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] PCI: Remove WARN_ON(in_interrupt()).
2021-02-08 19:44 [PATCH] PCI: Remove WARN_ON(in_interrupt()) Sebastian Andrzej Siewior
@ 2021-02-10 23:01 ` Bjorn Helgaas
0 siblings, 0 replies; 2+ messages in thread
From: Bjorn Helgaas @ 2021-02-10 23:01 UTC (permalink / raw)
To: Sebastian Andrzej Siewior; +Cc: linux-pci, Bjorn Helgaas, Thomas Gleixner
On Mon, Feb 08, 2021 at 08:44:00PM +0100, Sebastian Andrzej Siewior wrote:
> WARN_ON(in_interrupt()) is used for historic reasons to ensure proper
> usage of down_read() and predates might_sleep() and lockdep.
>
> down_read() has might_sleep() which also catches users from preemption
> disabled regions while in_interrupt() does not.
>
> Remove WARN_ON(in_interrupt()) because there is better debugging
> facility.
>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Applied to pci/misc for v5.12, thanks!
> ---
> drivers/pci/search.c | 4 ----
> 1 file changed, 4 deletions(-)
>
> diff --git a/drivers/pci/search.c b/drivers/pci/search.c
> index 2061672954ee3..b4c138a6ec025 100644
> --- a/drivers/pci/search.c
> +++ b/drivers/pci/search.c
> @@ -168,7 +168,6 @@ struct pci_bus *pci_find_next_bus(const struct pci_bus *from)
> struct list_head *n;
> struct pci_bus *b = NULL;
>
> - WARN_ON(in_interrupt());
> down_read(&pci_bus_sem);
> n = from ? from->node.next : pci_root_buses.next;
> if (n != &pci_root_buses)
> @@ -196,7 +195,6 @@ struct pci_dev *pci_get_slot(struct pci_bus *bus, unsigned int devfn)
> {
> struct pci_dev *dev;
>
> - WARN_ON(in_interrupt());
> down_read(&pci_bus_sem);
>
> list_for_each_entry(dev, &bus->devices, bus_list) {
> @@ -274,7 +272,6 @@ static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id,
> struct device *dev_start = NULL;
> struct pci_dev *pdev = NULL;
>
> - WARN_ON(in_interrupt());
> if (from)
> dev_start = &from->dev;
> dev = bus_find_device(&pci_bus_type, dev_start, (void *)id,
> @@ -381,7 +378,6 @@ int pci_dev_present(const struct pci_device_id *ids)
> {
> struct pci_dev *found = NULL;
>
> - WARN_ON(in_interrupt());
> while (ids->vendor || ids->subvendor || ids->class_mask) {
> found = pci_get_dev_by_id(ids, NULL);
> if (found) {
> --
> 2.30.0
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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