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Subject[02/03] Sample patch for [PATCH v4 03/15]
NOTE:This doesn't target the comment about changing exported
symbol name.

---
drivers/pci/hotplug/pci_hotplug_core.c | 18 +---
drivers/pci/hotplug/pciehp_core.c | 15 ----
drivers/pci/hotplug/shpchp_core.c | 15 ----
drivers/pci/slot.c | 123 ++++++++++++++++++++++++++-------
include/linux/pci.h | 4 -
5 files changed, 107 insertions(+), 68 deletions(-)
Index: hotplug/drivers/pci/hotplug/pciehp_core.c
===================================================================
--- hotplug.orig/drivers/pci/hotplug/pciehp_core.c
+++ hotplug/drivers/pci/hotplug/pciehp_core.c
@@ -196,7 +196,6 @@ static int init_slots(struct controller
struct slot *slot;
struct hotplug_slot *hotplug_slot;
struct hotplug_slot_info *info;
- int len, dup = 1;
int retval = -ENOMEM;

list_for_each_entry(slot, &ctrl->slot_list, slot_list) {
@@ -223,25 +222,11 @@ static int init_slots(struct controller
ctrl_dbg(ctrl, "Registering bus=%x dev=%x hp_slot=%x sun=%x "
"slot_device_offset=%x\n", slot->bus, slot->device,
slot->hp_slot, slot->number, ctrl->slot_device_offset);
-duplicate_name:
retval = pci_hp_register(hotplug_slot,
ctrl->pci_dev->subordinate,
slot->device,
slot->name);
if (retval) {
- /*
- * If slot N already exists, we'll try to create
- * slot N-1, N-2 ... N-M, until we overflow.
- */
- if (retval == -EEXIST) {
- len = snprintf(slot->name, SLOT_NAME_SIZE,
- "%d-%d", slot->number, dup++);
- if (len < SLOT_NAME_SIZE)
- goto duplicate_name;
- else
- ctrl_err(ctrl, "duplicate slot name "
- "overflow\n");
- }
ctrl_err(ctrl, "pci_hp_register failed with error %d\n",
retval);
goto error_info;
Index: hotplug/drivers/pci/hotplug/shpchp_core.c
===================================================================
--- hotplug.orig/drivers/pci/hotplug/shpchp_core.c
+++ hotplug/drivers/pci/hotplug/shpchp_core.c
@@ -102,7 +102,7 @@ static int init_slots(struct controller
struct hotplug_slot *hotplug_slot;
struct hotplug_slot_info *info;
int retval = -ENOMEM;
- int i, len, dup = 1;
+ int i;

for (i = 0; i < ctrl->num_slots; i++) {
slot = kzalloc(sizeof(*slot), GFP_KERNEL);
@@ -144,23 +144,10 @@ static int init_slots(struct controller
dbg("Registering bus=%x dev=%x hp_slot=%x sun=%x "
"slot_device_offset=%x\n", slot->bus, slot->device,
slot->hp_slot, slot->number, ctrl->slot_device_offset);
-duplicate_name:
retval = pci_hp_register(slot->hotplug_slot,
ctrl->pci_dev->subordinate, slot->device,
hotplug_slot->name);
if (retval) {
- /*
- * If slot N already exists, we'll try to create
- * slot N-1, N-2 ... N-M, until we overflow.
- */
- if (retval == -EEXIST) {
- len = snprintf(slot->name, SLOT_NAME_SIZE,
- "%d-%d", slot->number, dup++);
- if (len < SLOT_NAME_SIZE)
- goto duplicate_name;
- else
- err("duplicate slot name overflow\n");
- }
err("pci_hp_register failed with error %d\n", retval);
goto error_info;
}
Index: hotplug/include/linux/pci.h
===================================================================
--- hotplug.orig/include/linux/pci.h
+++ hotplug/include/linux/pci.h
@@ -509,8 +509,10 @@ struct pci_bus *pci_add_new_bus(struct p
int busnr);
struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
const char *name);
+struct pci_slot *pci_get_pci_slot(struct pci_bus *parent, int slot_nr);
void pci_destroy_slot(struct pci_slot *slot);
-void pci_update_slot_number(struct pci_slot *slot, int slot_nr);
+int pci_rename_slot(struct pci_slot *slot, const char *name);
+void pci_renumber_slot(struct pci_slot *slot, int slot_nr);
int pci_scan_slot(struct pci_bus *bus, int devfn);
struct pci_dev *pci_scan_single_device(struct pci_bus *bus, int devfn);
void pci_device_add(struct pci_dev *dev, struct pci_bus *bus);
Index: hotplug/drivers/pci/hotplug/pci_hotplug_core.c
===================================================================
--- hotplug.orig/drivers/pci/hotplug/pci_hotplug_core.c
+++ hotplug/drivers/pci/hotplug/pci_hotplug_core.c
@@ -569,12 +569,6 @@ int pci_hp_register(struct hotplug_slot

mutex_lock(&pci_hp_mutex);

- /* Check if we have already registered a slot with the same name. */
- if (get_slot_from_name(name)) {
- result = -EEXIST;
- goto out;
- }
-
/*
* No problems if we call this interface from both ACPI_PCI_SLOT
* driver and call it here again. If we've already created the
@@ -590,18 +584,14 @@ int pci_hp_register(struct hotplug_slot
goto cleanup;
}

- slot->pci_slot = pci_slot;
- pci_slot->hotplug = slot;
-
/*
* Allow pcihp drivers to override the ACPI_PCI_SLOT name.
*/
- if (strcmp(kobject_name(&pci_slot->kobj), name)) {
- result = kobject_rename(&pci_slot->kobj, name);
- if (result)
- goto cleanup;
- }
+ if ((result = pci_rename_slot(pci_slot, name)))
+ goto cleanup;

+ slot->pci_slot = pci_slot;
+ pci_slot->hotplug = slot;
list_add(&slot->slot_list, &pci_hotplug_slot_list);

result = fs_add_slot(pci_slot);
Index: hotplug/drivers/pci/slot.c
===================================================================
--- hotplug.orig/drivers/pci/slot.c
+++ hotplug/drivers/pci/slot.c
@@ -78,6 +78,46 @@ static struct kobj_type pci_slot_ktype =
.default_attrs = pci_slot_default_attrs,
};

+static char *make_slot_name(struct pci_slot *slot, const char *name)
+{
+ char *new_name;
+ int len, max, dup;
+
+ new_name = kstrdup(name, GFP_KERNEL);
+ if (!new_name)
+ return NULL;
+
+ /*
+ * Make sure we hit the realloc case the first time through the
+ * loop. 'len' will be strlen(name) + 3 at that point which is
+ * enough space for "name-X" and the trailing NUL.
+ */
+ len = strlen(name) + 2;
+ max = 1;
+ dup = 1;
+
+ for (;;) {
+ struct kobject *dup_slot;
+ dup_slot = kset_find_obj(pci_slots_kset, new_name);
+ if (!dup_slot)
+ break;
+ kobject_put(dup_slot);
+ if (dup_slot == &slot->kobj)
+ break;
+ if (dup == max) {
+ len++;
+ max *= 10;
+ kfree(new_name);
+ new_name = kmalloc(len, GFP_KERNEL);
+ if (!new_name)
+ break;
+ }
+ sprintf(new_name, "%s-%d", name, dup++);
+ }
+
+ return new_name;
+}
+
/**
* pci_create_slot - create or increment refcount for physical PCI slot
* @parent: struct pci_bus of parent bridge
@@ -89,7 +129,19 @@ static struct kobj_type pci_slot_ktype =
* either return a new &struct pci_slot to the caller, or if the pci_slot
* already exists, its refcount will be incremented.
*
- * Slots are uniquely identified by a @pci_bus, @slot_nr, @name tuple.
+ * Slots are uniquely identified by a @pci_bus, @slot_nr tuple.
+ *
+ * The kobject API imposes a restriction on us, and does not allow sysfs
+ * entries with duplicate names. There are known platforms with broken
+ * firmware that assign the same name to multiple slots.
+ *
+ * We workaround these broken platforms by renaming the slots on behalf
+ * of the caller. If firmware assigns name N to multiple slots:
+ *
+ * The first slot is assigned N
+ * The second slot is assigned N-1
+ * The third slot is assigned N-2
+ * etc.
*
* Placeholder slots:
* In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify
@@ -98,24 +150,20 @@ static struct kobj_type pci_slot_ktype =
* the slot. In this scenario, the caller may pass -1 for @slot_nr.
*
* The following semantics are imposed when the caller passes @slot_nr ==
- * -1. First, the check for existing %struct pci_slot is skipped, as the
- * caller may know about several unpopulated slots on a given %struct
- * pci_bus, and each slot would have a @slot_nr of -1. Uniqueness for
- * these slots is then determined by the @name parameter. We expect
- * kobject_init_and_add() to warn us if the caller attempts to create
- * multiple slots with the same name. The other change in semantics is
+ * -1. First, we no longer check for an existing %struct pci_slot, as there
+ * may be many slots with @slot_nr of -1. The other change in semantics is
* user-visible, which is the 'address' parameter presented in sysfs will
* consist solely of a dddd:bb tuple, where dddd is the PCI domain of the
* %struct pci_bus and bb is the bus number. In other words, the devfn of
* the 'placeholder' slot will not be displayed.
*/
-
struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
const char *name)
{
struct pci_dev *dev;
struct pci_slot *slot;
int err;
+ char *slot_name = NULL;

down_write(&pci_bus_sem);

@@ -144,18 +192,23 @@ placeholder:

slot->bus = parent;
slot->number = slot_nr;
-
slot->kobj.kset = pci_slots_kset;
+
+ slot_name = make_slot_name(slot, name);
+ if (!slot_name) {
+ err = -ENOMEM;
+ goto err;
+ }
+
err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL,
- "%s", name);
+ "%s", slot_name);
if (err) {
- printk(KERN_ERR "Unable to register kobject %s\n", name);
+ printk(KERN_ERR "Unable to register kobject %s\n", slot_name);
goto err;
}

INIT_LIST_HEAD(&slot->list);
list_add(&slot->list, &parent->slots);
-
list_for_each_entry(dev, &parent->devices, bus_list)
if (PCI_SLOT(dev->devfn) == slot_nr)
dev->slot = slot;
@@ -166,6 +219,7 @@ placeholder:

out:
up_write(&pci_bus_sem);
+ kfree(slot_name);
return slot;
err:
kfree(slot);
@@ -175,7 +229,35 @@ placeholder:
EXPORT_SYMBOL_GPL(pci_create_slot);

/**
- * pci_update_slot_number - update %struct pci_slot -> number
+ * pci_rename_slot - update %struct pci_slot -> name
+ * @slot - %struct pci_slot to update
+ * @name - new requested name for slot
+ *
+ * Allow caller to safely rename a %struct pci_slot without making
+ * the kobject core complain about duplicate names.
+ */
+int pci_rename_slot(struct pci_slot *slot, const char *name)
+{
+ int result = 0;
+ char *slot_name;
+
+ down_write(&pci_bus_sem);
+ slot_name = make_slot_name(slot, name);
+ if (!slot_name) {
+ result = -ENOMEM;
+ goto out;
+ }
+ if (strcmp(kobject_name(&slot->kobj), slot_name))
+ result = kobject_rename(&slot->kobj, slot_name);
+ kfree(slot_name);
+out:
+ up_write(&pci_bus_sem);
+ return result;
+}
+EXPORT_SYMBOL_GPL(pci_rename_slot);
+
+/**
+ * pci_renumber_slot - update %struct pci_slot -> number
* @slot - %struct pci_slot to update
* @slot_nr - new number for slot
*
@@ -183,27 +265,21 @@ EXPORT_SYMBOL_GPL(pci_create_slot);
* created a placeholder slot in pci_create_slot() by passing a -1 as
* slot_nr, to update their %struct pci_slot with the correct @slot_nr.
*/
-
-void pci_update_slot_number(struct pci_slot *slot, int slot_nr)
+void pci_renumber_slot(struct pci_slot *slot, int slot_nr)
{
- int name_count = 0;
struct pci_slot *tmp;

down_write(&pci_bus_sem);

list_for_each_entry(tmp, &slot->bus->slots, list) {
WARN_ON(tmp->number == slot_nr);
- if (!strcmp(kobject_name(&tmp->kobj), kobject_name(&slot->kobj)))
- name_count++;
+ goto out;
}
-
- if (name_count > 1)
- printk(KERN_WARNING "pci_update_slot_number found %d slots with the same name: %s\n", name_count, kobject_name(&slot->kobj));
-
slot->number = slot_nr;
+out:
up_write(&pci_bus_sem);
}
-EXPORT_SYMBOL_GPL(pci_update_slot_number);
+EXPORT_SYMBOL_GPL(pci_renumber_slot);

/**
* pci_destroy_slot - decrement refcount for physical PCI slot
@@ -213,7 +289,6 @@ EXPORT_SYMBOL_GPL(pci_update_slot_number
* just call kobject_put on its kobj and let our release methods do the
* rest.
*/
-
void pci_destroy_slot(struct pci_slot *slot)
{
pr_debug("%s: dec refcount to %d on %04x:%02x:%02x\n", __func__,



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