[PATCH] shpchp: fix improper wait for command completion

Current SHPCHP driver uses msleep_interruptible() function to wait for
a command completion event. But I think this would cause an unnecessary
long wait until timeout, if command completion interrupt came before
task state was changed to TASK_INTERRUPTIBLE. This patch fixes this
issue. With this patch, command completion becomes faster as follows:

o Without this patch

	# time echo 1 > power

	real    0m4.708s
	user    0m0.000s
	sys     0m0.524s

o With this patch

	# time echo 1 > power

	real    0m2.221s
	user    0m0.000s
	sys     0m0.532s

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/pci/hotplug/shpchp.h b/drivers/pci/hotplug/shpchp.h
index 55b0cd15f3485b47d4ccce8e0f144e8e7155fc6f..ce0e9b6ce83378fa416e9f6ed46a7562a0c64689 100644 (file)
--- a/drivers/pci/hotplug/shpchp.h
+++ b/drivers/pci/hotplug/shpchp.h
@@ -101,6 +101,7 @@ struct controller {
        u32 cap_offset;
        unsigned long mmio_base;
        unsigned long mmio_size;
+       volatile int cmd_busy;
 };
 
 struct hotplug_params {

diff --git a/drivers/pci/hotplug/shpchp_ctrl.c b/drivers/pci/hotplug/shpchp_ctrl.c
index 58619359ad08f33662ba6a45166ef78ef2e66d68..25ccb0e475936b93e1fbda46d3b5154fa98d6e16 100644 (file)
--- a/drivers/pci/hotplug/shpchp_ctrl.c
+++ b/drivers/pci/hotplug/shpchp_ctrl.c
@@ -248,7 +248,6 @@ static int change_bus_speed(struct controller *ctrl, struct slot *p_slot,
                up(&ctrl->crit_sect);
                return WRONG_BUS_FREQUENCY;
        }
-       wait_for_ctrl_irq (ctrl);
                
        if ((rc = p_slot->hpc_ops->check_cmd_status(ctrl))) {
                err("%s: Can't set bus speed/mode in the case of adapter & bus mismatch\n",
@@ -330,9 +329,6 @@ static int board_added(struct slot *p_slot)
                up(&ctrl->crit_sect);
                return -1;
        }
-                       
-       /* Wait for the command to complete */
-       wait_for_ctrl_irq (ctrl);
        
        rc = p_slot->hpc_ops->check_cmd_status(ctrl);
        if (rc) {
@@ -352,7 +348,6 @@ static int board_added(struct slot *p_slot)
                        up(&ctrl->crit_sect);
                        return WRONG_BUS_FREQUENCY;
                }
-               wait_for_ctrl_irq (ctrl);
                
                if ((rc = p_slot->hpc_ops->check_cmd_status(ctrl))) {
                        err("%s: Can't set bus speed/mode in the case of adapter & bus mismatch\n",
@@ -367,7 +362,6 @@ static int board_added(struct slot *p_slot)
                        up(&ctrl->crit_sect);
                        return rc;
                }
-               wait_for_ctrl_irq (ctrl);
 
                if ((rc = p_slot->hpc_ops->check_cmd_status(ctrl))) {
                        err("%s: Failed to enable slot, error code(%d)\n", __FUNCTION__, rc);
@@ -494,7 +488,6 @@ static int board_added(struct slot *p_slot)
                up(&ctrl->crit_sect);
                return rc;
        }
-       wait_for_ctrl_irq (ctrl);
 
        if ((rc = p_slot->hpc_ops->check_cmd_status(ctrl))) {
                err("%s: Failed to enable slot, error code(%d)\n", __FUNCTION__, rc);
@@ -532,9 +525,6 @@ static int board_added(struct slot *p_slot)
 
        p_slot->hpc_ops->green_led_on(p_slot);
 
-       /* Wait for the command to complete */
-       wait_for_ctrl_irq (ctrl);
-
        /* Done with exclusive hardware access */
        up(&ctrl->crit_sect);
 
@@ -552,8 +542,6 @@ err_exit:
                up(&ctrl->crit_sect);
                return rc;
        }
-       /* Wait for the command to complete */
-       wait_for_ctrl_irq (ctrl);
 
        rc = p_slot->hpc_ops->check_cmd_status(ctrl);
        if (rc) {
@@ -603,8 +591,6 @@ static int remove_board(struct slot *p_slot)
                up(&ctrl->crit_sect);
                return rc;
        }
-       /* Wait for the command to complete */
-       wait_for_ctrl_irq (ctrl);
 
        rc = p_slot->hpc_ops->check_cmd_status(ctrl);
        if (rc) {
@@ -621,8 +607,6 @@ static int remove_board(struct slot *p_slot)
                up(&ctrl->crit_sect);
                return rc;
        }
-       /* Wait for the command to complete */
-       wait_for_ctrl_irq (ctrl);
 
        /* Done with exclusive hardware access */
        up(&ctrl->crit_sect);
@@ -676,9 +660,6 @@ static void shpchp_pushbutton_thread (unsigned long slot)
 
                        p_slot->hpc_ops->green_led_off(p_slot);
 
-                       /* Wait for the command to complete */
-                       wait_for_ctrl_irq (p_slot->ctrl);
-
                        /* Done with exclusive hardware access */
                        up(&p_slot->ctrl->crit_sect);
                }
@@ -790,14 +771,9 @@ static void interrupt_event_handler(struct controller *ctrl)
                                                down(&ctrl->crit_sect);
 
                                                p_slot->hpc_ops->green_led_on(p_slot);
-                                               /* Wait for the command to complete */
-                                               wait_for_ctrl_irq (ctrl);
 
                                                p_slot->hpc_ops->set_attention_status(p_slot, 0);
 
-                                               /* Wait for the command to complete */
-                                               wait_for_ctrl_irq (ctrl);
-
                                                /* Done with exclusive hardware access */
                                                up(&ctrl->crit_sect);
                                                break;
@@ -806,12 +782,8 @@ static void interrupt_event_handler(struct controller *ctrl)
                                                down(&ctrl->crit_sect);
 
                                                p_slot->hpc_ops->green_led_off(p_slot);
-                                               /* Wait for the command to complete */
-                                               wait_for_ctrl_irq (ctrl);
 
                                                p_slot->hpc_ops->set_attention_status(p_slot, 0);
-                                               /* Wait for the command to complete */
-                                               wait_for_ctrl_irq (ctrl);
 
                                                /* Done with exclusive hardware access */
                                                up(&ctrl->crit_sect);
@@ -845,14 +817,9 @@ static void interrupt_event_handler(struct controller *ctrl)
 
                                        /* blink green LED and turn off amber */
                                        p_slot->hpc_ops->green_led_blink(p_slot);
-                                       /* Wait for the command to complete */
-                                       wait_for_ctrl_irq (ctrl);
                                        
                                        p_slot->hpc_ops->set_attention_status(p_slot, 0);
 
-                                       /* Wait for the command to complete */
-                                       wait_for_ctrl_irq (ctrl);
-
                                        /* Done with exclusive hardware access */
                                        up(&ctrl->crit_sect);
 
@@ -870,12 +837,8 @@ static void interrupt_event_handler(struct controller *ctrl)
                                        down(&ctrl->crit_sect);
 
                                        p_slot->hpc_ops->set_attention_status(p_slot, 1);
-                                       /* Wait for the command to complete */
-                                       wait_for_ctrl_irq (ctrl);
                                        
                                        p_slot->hpc_ops->green_led_off(p_slot);
-                                       /* Wait for the command to complete */
-                                       wait_for_ctrl_irq (ctrl);
 
                                        /* Done with exclusive hardware access */
                                        up(&ctrl->crit_sect);

diff --git a/drivers/pci/hotplug/shpchp_hpc.c b/drivers/pci/hotplug/shpchp_hpc.c
index f25e11645071c7fb56d1b2f36cb40b409128b758..b4226ff3a8544bd2740786f99d15698bc49435e4 100644 (file)
--- a/drivers/pci/hotplug/shpchp_hpc.c
+++ b/drivers/pci/hotplug/shpchp_hpc.c
@@ -275,6 +275,25 @@ static void start_int_poll_timer(struct php_ctlr_state_s *php_ctlr, int seconds)
        return;
 }
 
+static inline int shpc_wait_cmd(struct controller *ctrl)
+{
+       int retval = 0;
+       unsigned int timeout_msec = shpchp_poll_mode ? 2000 : 1000;
+       unsigned long timeout = msecs_to_jiffies(timeout_msec);
+       int rc = wait_event_interruptible_timeout(ctrl->queue,
+                                                 !ctrl->cmd_busy, timeout);
+       if (!rc) {
+               retval = -EIO;
+               err("Command not completed in %d msec\n", timeout_msec);
+       } else if (rc < 0) {
+               retval = -EINTR;
+               info("Command was interrupted by a signal\n");
+       }
+       ctrl->cmd_busy = 0;
+
+       return retval;
+}
+
 static int shpc_write_cmd(struct slot *slot, u8 t_slot, u8 cmd)
 {
        struct php_ctlr_state_s *php_ctlr = slot->ctrl->hpc_ctlr_handle;
@@ -314,8 +333,14 @@ static int shpc_write_cmd(struct slot *slot, u8 t_slot, u8 cmd)
        /* To make sure the Controller Busy bit is 0 before we send out the
         * command. 
         */
+       slot->ctrl->cmd_busy = 1;
        writew(temp_word, php_ctlr->creg + CMD);
 
+       /*
+        * Wait for command completion.
+        */
+       retval = shpc_wait_cmd(slot->ctrl);
+
        DBG_LEAVE_ROUTINE 
        return retval;
 }
@@ -1064,6 +1089,7 @@ static irqreturn_t shpc_isr(int IRQ, void *dev_id, struct pt_regs *regs)
                temp_dword = readl(php_ctlr->creg + SERR_INTR_ENABLE);
                temp_dword &= 0xfffdffff;
                writel(temp_dword, php_ctlr->creg + SERR_INTR_ENABLE);
+               ctrl->cmd_busy = 0;
                wake_up_interruptible(&ctrl->queue);
        }