vga_switcheroo: Refactor using linked list

Refactor the code base a bit for the further work to adapt more clients.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 110 insertions, 99 deletions

diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index 9d830286f883..da29da6aadac 100644
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -39,6 +39,7 @@ struct vga_switcheroo_client {
         bool (*can_switch)(struct pci_dev *pdev);
         int id;
         bool active;
+        struct list_head list;
 };
 
 static DEFINE_MUTEX(vgasr_mutex);
@@ -53,7 +54,7 @@ struct vgasr_priv {
         struct dentry *switch_file;
 
         int registered_clients;
-        struct vga_switcheroo_client clients[VGA_SWITCHEROO_MAX_CLIENTS];
+        struct list_head clients;
 
         struct vga_switcheroo_handler *handler;
 };
@@ -62,7 +63,9 @@ static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv);
 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv);
 
 /* only one switcheroo per system */
-static struct vgasr_priv vgasr_priv;
+static struct vgasr_priv vgasr_priv = {
+        .clients = LIST_HEAD_INIT(vgasr_priv.clients),
+};
 
 int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler)
 {
@@ -88,17 +91,18 @@ EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
 
 static void vga_switcheroo_enable(void)
 {
-        int i;
         int ret;
+        struct vga_switcheroo_client *client;
+
         /* call the handler to init */
         vgasr_priv.handler->init();
 
-        for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
-                ret = vgasr_priv.handler->get_client_id(vgasr_priv.clients[i].pdev);
+        list_for_each_entry(client, &vgasr_priv.clients, list) {
+                ret = vgasr_priv.handler->get_client_id(client->pdev);
                 if (ret < 0)
                         return;
 
-                vgasr_priv.clients[i].id = ret;
+                client->id = ret;
         }
         vga_switcheroo_debugfs_init(&vgasr_priv);
         vgasr_priv.active = true;
@@ -109,28 +113,27 @@ int vga_switcheroo_register_client(struct pci_dev *pdev,
                                    void (*reprobe)(struct pci_dev *pdev),
                                    bool (*can_switch)(struct pci_dev *pdev))
 {
-        int index;
+        struct vga_switcheroo_client *client;
 
-        mutex_lock(&vgasr_mutex);
-        /* don't do IGD vs DIS here */
-        if (vgasr_priv.registered_clients & 1)
-                index = 1;
-        else
-                index = 0;
-
-        vgasr_priv.clients[index].pwr_state = VGA_SWITCHEROO_ON;
-        vgasr_priv.clients[index].pdev = pdev;
-        vgasr_priv.clients[index].set_gpu_state = set_gpu_state;
-        vgasr_priv.clients[index].reprobe = reprobe;
-        vgasr_priv.clients[index].can_switch = can_switch;
-        vgasr_priv.clients[index].id = -1;
+        client = kzalloc(sizeof(*client), GFP_KERNEL);
+        if (!client)
+                return -ENOMEM;
+
+        client->pwr_state = VGA_SWITCHEROO_ON;
+        client->pdev = pdev;
+        client->set_gpu_state = set_gpu_state;
+        client->reprobe = reprobe;
+        client->can_switch = can_switch;
+        client->id = -1;
         if (pdev == vga_default_device())
-                vgasr_priv.clients[index].active = true;
+                client->active = true;
 
-        vgasr_priv.registered_clients |= (1 << index);
+        mutex_lock(&vgasr_mutex);
+        list_add_tail(&client->list, &vgasr_priv.clients);
+        vgasr_priv.registered_clients++;
 
         /* if we get two clients + handler */
-        if (vgasr_priv.registered_clients == 0x3 && vgasr_priv.handler) {
+        if (vgasr_priv.registered_clients == 2 && vgasr_priv.handler) {
                 printk(KERN_INFO "vga_switcheroo: enabled\n");
                 vga_switcheroo_enable();
         }
@@ -139,18 +142,47 @@ int vga_switcheroo_register_client(struct pci_dev *pdev,
 }
 EXPORT_SYMBOL(vga_switcheroo_register_client);
 
+static struct vga_switcheroo_client *
+find_client_from_pci(struct list_head *head, struct pci_dev *pdev)
+{
+        struct vga_switcheroo_client *client;
+        list_for_each_entry(client, head, list)
+                if (client->pdev == pdev)
+                        return client;
+        return NULL;
+}
+
+static struct vga_switcheroo_client *
+find_client_from_id(struct list_head *head, int client_id)
+{
+        struct vga_switcheroo_client *client;
+        list_for_each_entry(client, head, list)
+                if (client->id == client_id)
+                        return client;
+        return NULL;
+}
+
+static struct vga_switcheroo_client *
+find_active_client(struct list_head *head)
+{
+        struct vga_switcheroo_client *client;
+        list_for_each_entry(client, head, list)
+                if (client->active == true)
+                        return client;
+        return NULL;
+}
+
 void vga_switcheroo_unregister_client(struct pci_dev *pdev)
 {
-        int i;
+        struct vga_switcheroo_client *client;
 
         mutex_lock(&vgasr_mutex);
-        for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
-                if (vgasr_priv.clients[i].pdev == pdev) {
-                        vgasr_priv.registered_clients &= ~(1 << i);
-                        break;
-                }
+        client = find_client_from_pci(&vgasr_priv.clients, pdev);
+        if (client) {
+                list_del(&client->list);
+                kfree(client);
+                vgasr_priv.registered_clients--;
         }
-
         printk(KERN_INFO "vga_switcheroo: disabled\n");
         vga_switcheroo_debugfs_fini(&vgasr_priv);
         vgasr_priv.active = false;
@@ -161,29 +193,28 @@ EXPORT_SYMBOL(vga_switcheroo_unregister_client);
 void vga_switcheroo_client_fb_set(struct pci_dev *pdev,
                                  struct fb_info *info)
 {
-        int i;
+        struct vga_switcheroo_client *client;
 
         mutex_lock(&vgasr_mutex);
-        for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
-                if (vgasr_priv.clients[i].pdev == pdev) {
-                        vgasr_priv.clients[i].fb_info = info;
-                        break;
-                }
-        }
+        client = find_client_from_pci(&vgasr_priv.clients, pdev);
+        if (client)
+                client->fb_info = info;
         mutex_unlock(&vgasr_mutex);
 }
 EXPORT_SYMBOL(vga_switcheroo_client_fb_set);
 
 static int vga_switcheroo_show(struct seq_file *m, void *v)
 {
-        int i;
+        struct vga_switcheroo_client *client;
+        int i = 0;
         mutex_lock(&vgasr_mutex);
-        for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
+        list_for_each_entry(client, &vgasr_priv.clients, list) {
                 seq_printf(m, "%d:%s:%c:%s:%s\n", i,
-                           vgasr_priv.clients[i].id == VGA_SWITCHEROO_DIS ? "DIS" : "IGD",
-                           vgasr_priv.clients[i].active ? '+' : ' ',
-                           vgasr_priv.clients[i].pwr_state ? "Pwr" : "Off",
-                           pci_name(vgasr_priv.clients[i].pdev));
+                           client->id == VGA_SWITCHEROO_DIS ? "DIS" : "IGD",
+                           client->active ? '+' : ' ',
+                           client->pwr_state ? "Pwr" : "Off",
+                           pci_name(client->pdev));
+                i++;
         }
         mutex_unlock(&vgasr_mutex);
         return 0;
@@ -217,15 +248,9 @@ static int vga_switchoff(struct vga_switcheroo_client *client)
 /* stage one happens before delay */
 static int vga_switchto_stage1(struct vga_switcheroo_client *new_client)
 {
-        int i;
-        struct vga_switcheroo_client *active = NULL;
+        struct vga_switcheroo_client *active;
 
-        for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
-                if (vgasr_priv.clients[i].active == true) {
-                        active = &vgasr_priv.clients[i];
-                        break;
-                }
-        }
+        active = find_active_client(&vgasr_priv.clients);
         if (!active)
                 return 0;
 
@@ -241,15 +266,9 @@ static int vga_switchto_stage1(struct vga_switcheroo_client *new_client)
 static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
 {
         int ret;
-        int i;
-        struct vga_switcheroo_client *active = NULL;
+        struct vga_switcheroo_client *active;
 
-        for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
-                if (vgasr_priv.clients[i].active == true) {
-                        active = &vgasr_priv.clients[i];
-                        break;
-                }
-        }
+        active = find_active_client(&vgasr_priv.clients);
         if (!active)
                 return 0;
 
@@ -275,13 +294,26 @@ static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
         return 0;
 }
 
+static bool check_can_switch(void)
+{
+        struct vga_switcheroo_client *client;
+
+        list_for_each_entry(client, &vgasr_priv.clients, list) {
+                if (!client->can_switch(client->pdev)) {
+                        printk(KERN_ERR "vga_switcheroo: client %x refused switch\n", client->id);
+                        return false;
+                }
+        }
+        return true;
+}
+
 static ssize_t
 vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
                              size_t cnt, loff_t *ppos)
 {
         char usercmd[64];
         const char *pdev_name;
-        int i, ret;
+        int ret;
         bool delay = false, can_switch;
         bool just_mux = false;
         int client_id = -1;
@@ -302,21 +334,21 @@ vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
 
         /* pwr off the device not in use */
         if (strncmp(usercmd, "OFF", 3) == 0) {
-                for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
-                        if (vgasr_priv.clients[i].active)
+                list_for_each_entry(client, &vgasr_priv.clients, list) {
+                        if (client->active)
                                 continue;
-                        if (vgasr_priv.clients[i].pwr_state == VGA_SWITCHEROO_ON)
-                                vga_switchoff(&vgasr_priv.clients[i]);
+                        if (client->pwr_state == VGA_SWITCHEROO_ON)
+                                vga_switchoff(client);
                 }
                 goto out;
         }
         /* pwr on the device not in use */
         if (strncmp(usercmd, "ON", 2) == 0) {
-                for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
-                        if (vgasr_priv.clients[i].active)
+                list_for_each_entry(client, &vgasr_priv.clients, list) {
+                        if (client->active)
                                 continue;
-                        if (vgasr_priv.clients[i].pwr_state == VGA_SWITCHEROO_OFF)
-                                vga_switchon(&vgasr_priv.clients[i]);
+                        if (client->pwr_state == VGA_SWITCHEROO_OFF)
+                                vga_switchon(client);
                 }
                 goto out;
         }
@@ -349,13 +381,9 @@ vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
 
         if (client_id == -1)
                 goto out;
-
-        for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
-                if (vgasr_priv.clients[i].id == client_id) {
-                        client = &vgasr_priv.clients[i];
-                        break;
-                }
-        }
+        client = find_client_from_id(&vgasr_priv.clients, client_id);
+        if (!client)
+                goto out;
 
         vgasr_priv.delayed_switch_active = false;
 
@@ -364,23 +392,16 @@ vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
                 goto out;
         }
 
-        if (client->active == true)
+        if (client->active)
                 goto out;
 
         /* okay we want a switch - test if devices are willing to switch */
-        can_switch = true;
-        for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
-                can_switch = vgasr_priv.clients[i].can_switch(vgasr_priv.clients[i].pdev);
-                if (can_switch == false) {
-                        printk(KERN_ERR "vga_switcheroo: client %d refused switch\n", i);
-                        break;
-                }
-        }
+        can_switch = check_can_switch();
 
         if (can_switch == false && delay == false)
                 goto out;
 
-        if (can_switch == true) {
+        if (can_switch) {
                 pdev_name = pci_name(client->pdev);
                 ret = vga_switchto_stage1(client);
                 if (ret)
@@ -452,10 +473,8 @@ fail:
 
 int vga_switcheroo_process_delayed_switch(void)
 {
-        struct vga_switcheroo_client *client = NULL;
+        struct vga_switcheroo_client *client;
         const char *pdev_name;
-        bool can_switch = true;
-        int i;
         int ret;
         int err = -EINVAL;
 
@@ -465,17 +484,9 @@ int vga_switcheroo_process_delayed_switch(void)
 
         printk(KERN_INFO "vga_switcheroo: processing delayed switch to %d\n", vgasr_priv.delayed_client_id);
 
-        for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
-                if (vgasr_priv.clients[i].id == vgasr_priv.delayed_client_id)
-                        client = &vgasr_priv.clients[i];
-                can_switch = vgasr_priv.clients[i].can_switch(vgasr_priv.clients[i].pdev);
-                if (can_switch == false) {
-                        printk(KERN_ERR "vga_switcheroo: client %d refused switch\n", i);
-                        break;
-                }
-        }
-
-        if (can_switch == false || client == NULL)
+        client = find_client_from_id(&vgasr_priv.clients,
+                                     vgasr_priv.delayed_client_id);
+        if (!client || !check_can_switch())
                 goto err;
 
         pdev_name = pci_name(client->pdev);