When movable BARs are enabled, the PCI subsystem at first releases
all the bridge windows and then performs an attempt to assign new
requested resources and re-assign the existing ones.
If a hotplugged device gets its resources first, there could be no
space left to re-assign resources of already working devices, which
is unacceptable. If this happens, this patch marks one of the new
devices with the new introduced flag PCI_DEV_IGNORE and retries the
resource assignment.
This patch adds a new res_mask bitmask to the struct pci_dev for
storing the indices of assigned resources.
Signed-off-by: Sergey Miroshnichenko <s.miroshnichenko@xxxxxxxxx>
---
drivers/pci/bus.c | 5 ++
drivers/pci/pci.h | 11 +++++
drivers/pci/probe.c | 100 +++++++++++++++++++++++++++++++++++++++-
drivers/pci/setup-bus.c | 15 ++++++
include/linux/pci.h | 1 +
5 files changed, 130 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 5cb40b2518f9..a9784144d6f2 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -311,6 +311,11 @@ void pci_bus_add_device(struct pci_dev *dev)
{
int retval;
+ if (pci_dev_is_ignored(dev)) {
+ pci_warn(dev, "%s: don't enable the ignored device\n", __func__);
+ return;
+ }
+
/*
* Can not put in pci_device_add yet because resources
* are not assigned yet for some devices.
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index e06e8692a7b1..56b905068ac5 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -366,6 +366,7 @@ static inline bool pci_dev_is_disconnected(const struct pci_dev *dev)
/* pci_dev priv_flags */
#define PCI_DEV_ADDED 0
+#define PCI_DEV_IGNORE 1
static inline void pci_dev_assign_added(struct pci_dev *dev, bool added)
{
@@ -377,6 +378,16 @@ static inline bool pci_dev_is_added(const struct pci_dev *dev)
return test_bit(PCI_DEV_ADDED, &dev->priv_flags);
}
+static inline void pci_dev_ignore(struct pci_dev *dev, bool ignore)
+{
+ assign_bit(PCI_DEV_IGNORE, &dev->priv_flags, ignore);
+}
+
+static inline bool pci_dev_is_ignored(const struct pci_dev *dev)
+{
+ return test_bit(PCI_DEV_IGNORE, &dev->priv_flags);
+}
+
#ifdef CONFIG_PCIEAER
#include <linux/aer.h>
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 964faa32e78a..b7d2769d4a0e 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -3171,6 +3171,23 @@ unsigned int pci_rescan_bus_bridge_resize(struct pci_dev *bridge)
return max;
}
+static unsigned int pci_dev_res_mask(struct pci_dev *dev)
+{
+ unsigned int res_mask = 0;
+ int i;
+
+ for (i = 0; i < PCI_BRIDGE_RESOURCES; i++) {
+ struct resource *r = &dev->resource[i];
+
+ if (!r->flags || (r->flags & IORESOURCE_UNSET) || !r->parent)
+ continue;
+
+ res_mask |= (1 << i);
+ }
+
+ return res_mask;
+}
+
static void pci_bus_rescan_prepare(struct pci_bus *bus)
{
struct pci_dev *dev;
@@ -3178,6 +3195,8 @@ static void pci_bus_rescan_prepare(struct pci_bus *bus)
list_for_each_entry(dev, &bus->devices, bus_list) {
struct pci_bus *child = dev->subordinate;
+ dev->res_mask = pci_dev_res_mask(dev);
+
if (child) {
pci_bus_rescan_prepare(child);
} else if (dev->driver &&
@@ -3222,6 +3241,84 @@ static void pci_setup_bridges(struct pci_bus *bus)
pci_setup_bridge(bus);
}
+static struct pci_dev *pci_find_next_new_device(struct pci_bus *bus)
+{
+ struct pci_dev *dev;
+
+ if (!bus)
+ return NULL;
+
+ list_for_each_entry(dev, &bus->devices, bus_list) {
+ struct pci_bus *child_bus = dev->subordinate;
+
+ if (!pci_dev_is_added(dev) && !pci_dev_is_ignored(dev))
+ return dev;
+
+ if (child_bus) {
+ struct pci_dev *next_new_dev;
+
+ next_new_dev = pci_find_next_new_device(child_bus);
+ if (next_new_dev)
+ return next_new_dev;
+ }
+ }
+
+ return NULL;
+}
+
+static bool pci_bus_validate_resources(struct pci_bus *bus)
+{
+ struct pci_dev *dev;
+ bool ret = true;
+
+ if (!bus)
+ return false;
+
+ list_for_each_entry(dev, &bus->devices, bus_list) {
+ struct pci_bus *child = dev->subordinate;
+ unsigned int res_mask = pci_dev_res_mask(dev);
+
+ if (pci_dev_is_ignored(dev))
+ continue;
+
+ if (dev->res_mask & ~res_mask) {
+ pci_err(dev, "%s: Non-re-enabled resources found: 0x%x -> 0x%x\n",
+ __func__, res_mask, dev->res_mask);
+ ret = false;
+ }
+
+ if (child && !pci_bus_validate_resources(child))
+ ret = false;
+ }
+
+ return ret;
+}
+
+static void pci_reassign_root_bus_resources(struct pci_bus *root)
+{
+ do {
+ struct pci_dev *next_new_dev;
+
+ pci_bus_release_root_bridge_resources(root);
+ pci_assign_unassigned_root_bus_resources(root);
+
+ if (pci_bus_validate_resources(root))
+ break;
+
+ next_new_dev = pci_find_next_new_device(root);
+ if (!next_new_dev) {
+ dev_err(&root->dev, "%s: failed to re-assign resources even after ignoring all the hotplugged devices\n",
+ __func__);
+ break;
+ }
+
+ dev_warn(&root->dev, "%s: failed to re-assign resources, disable the next hotplugged device %s and retry\n",
+ __func__, dev_name(&next_new_dev->dev));
+
+ pci_dev_ignore(next_new_dev, true);
+ } while (true);
+}
+
/**
* pci_rescan_bus - Scan a PCI bus for devices
* @bus: PCI bus to scan
@@ -3245,8 +3342,7 @@ unsigned int pci_rescan_bus(struct pci_bus *bus)
max = pci_scan_child_bus(root);
- pci_bus_release_root_bridge_resources(root);
- pci_assign_unassigned_root_bus_resources(root);
+ pci_reassign_root_bus_resources(root);
pci_setup_bridges(root);
pci_bus_rescan_done(root);
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index a7594c302bd9..e0c5e2c947d6 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -131,6 +131,9 @@ static void pdev_sort_resources(struct pci_dev *dev, struct list_head *head)
{
int i;
+ if (pci_dev_is_ignored(dev))
+ return;
+
for (i = 0; i < PCI_NUM_RESOURCES; i++) {
struct resource *r;
struct pci_dev_resource *dev_res, *tmp;
@@ -181,6 +184,9 @@ static void __dev_sort_resources(struct pci_dev *dev,
{
u16 class = dev->class >> 8;
+ if (pci_dev_is_ignored(dev))
+ return;
+
/* Don't touch classless devices or host bridges or ioapics. */
if (class == PCI_CLASS_NOT_DEFINED || class == PCI_CLASS_BRIDGE_HOST)
return;
@@ -284,6 +290,9 @@ static void assign_requested_resources_sorted(struct list_head *head,
int idx;
list_for_each_entry(dev_res, head, list) {
+ if (pci_dev_is_ignored(dev_res->dev))
+ continue;
+
res = dev_res->res;
idx = res - &dev_res->dev->resource[0];
if (resource_size(res) &&
@@ -1028,6 +1037,9 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
list_for_each_entry(dev, &bus->devices, bus_list) {
int i;
+ if (pci_dev_is_ignored(dev))
+ continue;
+
for (i = 0; i < PCI_NUM_RESOURCES; i++) {
struct resource *r = &dev->resource[i];
resource_size_t r_size;
@@ -1385,6 +1397,9 @@ void __pci_bus_assign_resources(const struct pci_bus *bus,
pbus_assign_resources_sorted(bus, realloc_head, fail_head);
list_for_each_entry(dev, &bus->devices, bus_list) {
+ if (pci_dev_is_ignored(dev))
+ continue;
+
pdev_assign_fixed_resources(dev);
b = dev->subordinate;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index d87bbf9e0627..5a7d2b7ff31f 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -369,6 +369,7 @@ struct pci_dev {
*/
unsigned int irq;
struct resource resource[DEVICE_COUNT_RESOURCE]; /* I/O and memory regions + expansion ROMs */
+ unsigned int res_mask; /* Bitmask of assigned resources */
bool match_driver; /* Skip attaching driver */
--
2.20.1
