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[PATCH] shpchp - bugfix: add missing serialization
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Current shpchp driver might cause system panic because of lack of
serialization. It can be reproduced very easily by the following
operation.

	# cd /sys/bus/pci/slots/<slot#>
	# while true; do echo 0 > power ; echo 1 > power ; done &
	# while true; do echo 0 > power ; echo 1 > power ; done &

This patch fixes this issue by changing shpchp to get appropreate
semaphore for hot-plug operation.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Kenji Kaneshige authored and Greg Kroah-Hartman committed Mar 23, 2006
1 parent d29aadd commit ef3be54
Showing 1 changed file with 24 additions and 42 deletions.
66 changes: 24 additions & 42 deletions drivers/pci/hotplug/shpchp_ctrl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -307,15 +307,10 @@ static int board_added(struct slot *p_slot)
__FUNCTION__, p_slot->device,
ctrl->slot_device_offset, hp_slot);

/* Wait for exclusive access to hardware */
mutex_lock(&ctrl->crit_sect);

/* Power on slot without connecting to bus */
rc = p_slot->hpc_ops->power_on_slot(p_slot);
if (rc) {
err("%s: Failed to power on slot\n", __FUNCTION__);
/* Done with exclusive hardware access */
mutex_unlock(&ctrl->crit_sect);
return -1;
}

Expand All @@ -325,14 +320,12 @@ static int board_added(struct slot *p_slot)

if ((rc = p_slot->hpc_ops->set_bus_speed_mode(p_slot, PCI_SPEED_33MHz))) {
err("%s: Issue of set bus speed mode command failed\n", __FUNCTION__);
mutex_unlock(&ctrl->crit_sect);
return WRONG_BUS_FREQUENCY;
}

/* turn on board, blink green LED, turn off Amber LED */
if ((rc = p_slot->hpc_ops->slot_enable(p_slot))) {
err("%s: Issue of Slot Enable command failed\n", __FUNCTION__);
mutex_unlock(&ctrl->crit_sect);
return rc;
}
}
Expand All @@ -346,16 +339,12 @@ static int board_added(struct slot *p_slot)

if (rc || adapter_speed == PCI_SPEED_UNKNOWN) {
err("%s: Can't get adapter speed or bus mode mismatch\n", __FUNCTION__);
/* Done with exclusive hardware access */
mutex_unlock(&ctrl->crit_sect);
return WRONG_BUS_FREQUENCY;
}

rc = p_slot->hpc_ops->get_cur_bus_speed(p_slot, &bus_speed);
if (rc || bus_speed == PCI_SPEED_UNKNOWN) {
err("%s: Can't get bus operation speed\n", __FUNCTION__);
/* Done with exclusive hardware access */
mutex_unlock(&ctrl->crit_sect);
return WRONG_BUS_FREQUENCY;
}

Expand All @@ -365,9 +354,6 @@ static int board_added(struct slot *p_slot)
max_bus_speed = bus_speed;
}

/* Done with exclusive hardware access */
mutex_unlock(&ctrl->crit_sect);

if ((rc = p_slot->hpc_ops->get_prog_int(p_slot, &pi))) {
err("%s: Can't get controller programming interface, set it to 1\n", __FUNCTION__);
pi = 1;
Expand Down Expand Up @@ -744,29 +730,25 @@ static void interrupt_event_handler(struct controller *ctrl)
int shpchp_enable_slot (struct slot *p_slot)
{
u8 getstatus = 0;
int rc;
int rc, retval = -ENODEV;

/* Check to see if (latch closed, card present, power off) */
mutex_lock(&p_slot->ctrl->crit_sect);
rc = p_slot->hpc_ops->get_adapter_status(p_slot, &getstatus);
if (rc || !getstatus) {
info("%s: no adapter on slot(%x)\n", __FUNCTION__, p_slot->number);
mutex_unlock(&p_slot->ctrl->crit_sect);
return -ENODEV;
goto out;
}
rc = p_slot->hpc_ops->get_latch_status(p_slot, &getstatus);
if (rc || getstatus) {
info("%s: latch open on slot(%x)\n", __FUNCTION__, p_slot->number);
mutex_unlock(&p_slot->ctrl->crit_sect);
return -ENODEV;
goto out;
}
rc = p_slot->hpc_ops->get_power_status(p_slot, &getstatus);
if (rc || getstatus) {
info("%s: already enabled on slot(%x)\n", __FUNCTION__, p_slot->number);
mutex_unlock(&p_slot->ctrl->crit_sect);
return -ENODEV;
goto out;
}
mutex_unlock(&p_slot->ctrl->crit_sect);

p_slot->is_a_board = 1;

Expand All @@ -781,56 +763,56 @@ int shpchp_enable_slot (struct slot *p_slot)
&& p_slot->ctrl->num_slots == 1) {
/* handle amd pogo errata; this must be done before enable */
amd_pogo_errata_save_misc_reg(p_slot);
rc = board_added(p_slot);
retval = board_added(p_slot);
/* handle amd pogo errata; this must be done after enable */
amd_pogo_errata_restore_misc_reg(p_slot);
} else
rc = board_added(p_slot);
retval = board_added(p_slot);

if (rc) {
if (retval) {
p_slot->hpc_ops->get_adapter_status(p_slot,
&(p_slot->presence_save));
p_slot->hpc_ops->get_latch_status(p_slot, &getstatus);
}

update_slot_info(p_slot);
return rc;
out:
mutex_unlock(&p_slot->ctrl->crit_sect);
return retval;
}


int shpchp_disable_slot (struct slot *p_slot)
{
u8 getstatus = 0;
int ret = 0;
int rc, retval = -ENODEV;

if (!p_slot->ctrl)
return -ENODEV;

/* Check to see if (latch closed, card present, power on) */
mutex_lock(&p_slot->ctrl->crit_sect);

ret = p_slot->hpc_ops->get_adapter_status(p_slot, &getstatus);
if (ret || !getstatus) {
rc = p_slot->hpc_ops->get_adapter_status(p_slot, &getstatus);
if (rc || !getstatus) {
info("%s: no adapter on slot(%x)\n", __FUNCTION__, p_slot->number);
mutex_unlock(&p_slot->ctrl->crit_sect);
return -ENODEV;
goto out;
}
ret = p_slot->hpc_ops->get_latch_status(p_slot, &getstatus);
if (ret || getstatus) {
rc = p_slot->hpc_ops->get_latch_status(p_slot, &getstatus);
if (rc || getstatus) {
info("%s: latch open on slot(%x)\n", __FUNCTION__, p_slot->number);
mutex_unlock(&p_slot->ctrl->crit_sect);
return -ENODEV;
goto out;
}
ret = p_slot->hpc_ops->get_power_status(p_slot, &getstatus);
if (ret || !getstatus) {
rc = p_slot->hpc_ops->get_power_status(p_slot, &getstatus);
if (rc || !getstatus) {
info("%s: already disabled slot(%x)\n", __FUNCTION__, p_slot->number);
mutex_unlock(&p_slot->ctrl->crit_sect);
return -ENODEV;
goto out;
}
mutex_unlock(&p_slot->ctrl->crit_sect);

ret = remove_board(p_slot);
retval = remove_board(p_slot);
update_slot_info(p_slot);
return ret;
out:
mutex_unlock(&p_slot->ctrl->crit_sect);
return retval;
}

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