ieee1394: raw1394: narrow down the state_mutex protected region

Refactor the ioctl dispatcher in order to move a fraction of it out of
the section which is serialized by fi->state_mutex.  This is not so much
about performance but more about self-documentation:  The mutex_lock()/
mutex_unlock() calls are now closer to the data accesses which the mutex
protects, i.e. to the iso_state switch.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

1 files changed, 110 insertions, 101 deletions

diff --git a/drivers/ieee1394/raw1394.c b/drivers/ieee1394/raw1394.c
index 975ed7062aa1..d1594427601f 100644
--- a/drivers/ieee1394/raw1394.c
+++ b/drivers/ieee1394/raw1394.c
@@ -2556,102 +2556,106 @@ static int raw1394_mmap(struct file *file, struct vm_area_struct *vma)
         return ret;
 }
 
-/* ioctl is only used for rawiso operations */
-static long do_raw1394_ioctl(struct file *file, unsigned int cmd,
-                                                        unsigned long arg)
+static long raw1394_ioctl_inactive(struct file_info *fi, unsigned int cmd,
+                                   void __user *argp)
+{
+        switch (cmd) {
+        case RAW1394_IOC_ISO_XMIT_INIT:
+                return raw1394_iso_xmit_init(fi, argp);
+        case RAW1394_IOC_ISO_RECV_INIT:
+                return raw1394_iso_recv_init(fi, argp);
+        default:
+                return -EINVAL;
+        }
+}
+
+static long raw1394_ioctl_recv(struct file_info *fi, unsigned int cmd,
+                               unsigned long arg)
 {
-        struct file_info *fi = file->private_data;
         void __user *argp = (void __user *)arg;
 
-        switch (fi->iso_state) {
-        case RAW1394_ISO_INACTIVE:
-                switch (cmd) {
-                case RAW1394_IOC_ISO_XMIT_INIT:
-                        return raw1394_iso_xmit_init(fi, argp);
-                case RAW1394_IOC_ISO_RECV_INIT:
-                        return raw1394_iso_recv_init(fi, argp);
-                default:
-                        break;
+        switch (cmd) {
+        case RAW1394_IOC_ISO_RECV_START:{
+                        int args[3];
+
+                        if (copy_from_user(&args[0], argp, sizeof(args)))
+                                return -EFAULT;
+                        return hpsb_iso_recv_start(fi->iso_handle,
+                                                   args[0], args[1], args[2]);
                 }
-                break;
-        case RAW1394_ISO_RECV:
-                switch (cmd) {
-                case RAW1394_IOC_ISO_RECV_START:{
-                                /* copy args from user-space */
-                                int args[3];
-                                if (copy_from_user
-                                    (&args[0], argp, sizeof(args)))
-                                        return -EFAULT;
-                                return hpsb_iso_recv_start(fi->iso_handle,
-                                                           args[0], args[1],
-                                                           args[2]);
-                        }
-                case RAW1394_IOC_ISO_XMIT_RECV_STOP:
-                        hpsb_iso_stop(fi->iso_handle);
-                        return 0;
-                case RAW1394_IOC_ISO_RECV_LISTEN_CHANNEL:
-                        return hpsb_iso_recv_listen_channel(fi->iso_handle,
-                                                            arg);
-                case RAW1394_IOC_ISO_RECV_UNLISTEN_CHANNEL:
-                        return hpsb_iso_recv_unlisten_channel(fi->iso_handle,
-                                                              arg);
-                case RAW1394_IOC_ISO_RECV_SET_CHANNEL_MASK:{
-                                /* copy the u64 from user-space */
-                                u64 mask;
-                                if (copy_from_user(&mask, argp, sizeof(mask)))
-                                        return -EFAULT;
-                                return hpsb_iso_recv_set_channel_mask(fi->
-                                                                      iso_handle,
-                                                                      mask);
-                        }
-                case RAW1394_IOC_ISO_GET_STATUS:
-                        return raw1394_iso_get_status(fi, argp);
-                case RAW1394_IOC_ISO_RECV_PACKETS:
-                        return raw1394_iso_recv_packets(fi, argp);
-                case RAW1394_IOC_ISO_RECV_RELEASE_PACKETS:
-                        return hpsb_iso_recv_release_packets(fi->iso_handle,
-                                                             arg);
-                case RAW1394_IOC_ISO_RECV_FLUSH:
-                        return hpsb_iso_recv_flush(fi->iso_handle);
-                case RAW1394_IOC_ISO_SHUTDOWN:
-                        raw1394_iso_shutdown(fi);
-                        return 0;
-                case RAW1394_IOC_ISO_QUEUE_ACTIVITY:
-                        queue_rawiso_event(fi);
-                        return 0;
+        case RAW1394_IOC_ISO_XMIT_RECV_STOP:
+                hpsb_iso_stop(fi->iso_handle);
+                return 0;
+        case RAW1394_IOC_ISO_RECV_LISTEN_CHANNEL:
+                return hpsb_iso_recv_listen_channel(fi->iso_handle, arg);
+        case RAW1394_IOC_ISO_RECV_UNLISTEN_CHANNEL:
+                return hpsb_iso_recv_unlisten_channel(fi->iso_handle, arg);
+        case RAW1394_IOC_ISO_RECV_SET_CHANNEL_MASK:{
+                        u64 mask;
+
+                        if (copy_from_user(&mask, argp, sizeof(mask)))
+                                return -EFAULT;
+                        return hpsb_iso_recv_set_channel_mask(fi->iso_handle,
+                                                              mask);
                 }
-                break;
-        case RAW1394_ISO_XMIT:
-                switch (cmd) {
-                case RAW1394_IOC_ISO_XMIT_START:{
-                                /* copy two ints from user-space */
-                                int args[2];
-                                if (copy_from_user
-                                    (&args[0], argp, sizeof(args)))
-                                        return -EFAULT;
-                                return hpsb_iso_xmit_start(fi->iso_handle,
-                                                           args[0], args[1]);
-                        }
-                case RAW1394_IOC_ISO_XMIT_SYNC:
-                        return hpsb_iso_xmit_sync(fi->iso_handle);
-                case RAW1394_IOC_ISO_XMIT_RECV_STOP:
-                        hpsb_iso_stop(fi->iso_handle);
-                        return 0;
-                case RAW1394_IOC_ISO_GET_STATUS:
-                        return raw1394_iso_get_status(fi, argp);
-                case RAW1394_IOC_ISO_XMIT_PACKETS:
-                        return raw1394_iso_send_packets(fi, argp);
-                case RAW1394_IOC_ISO_SHUTDOWN:
-                        raw1394_iso_shutdown(fi);
-                        return 0;
-                case RAW1394_IOC_ISO_QUEUE_ACTIVITY:
-                        queue_rawiso_event(fi);
-                        return 0;
+        case RAW1394_IOC_ISO_GET_STATUS:
+                return raw1394_iso_get_status(fi, argp);
+        case RAW1394_IOC_ISO_RECV_PACKETS:
+                return raw1394_iso_recv_packets(fi, argp);
+        case RAW1394_IOC_ISO_RECV_RELEASE_PACKETS:
+                return hpsb_iso_recv_release_packets(fi->iso_handle, arg);
+        case RAW1394_IOC_ISO_RECV_FLUSH:
+                return hpsb_iso_recv_flush(fi->iso_handle);
+        case RAW1394_IOC_ISO_SHUTDOWN:
+                raw1394_iso_shutdown(fi);
+                return 0;
+        case RAW1394_IOC_ISO_QUEUE_ACTIVITY:
+                queue_rawiso_event(fi);
+                return 0;
+        default:
+                return -EINVAL;
+        }
+}
+
+static long raw1394_ioctl_xmit(struct file_info *fi, unsigned int cmd,
+                               void __user *argp)
+{
+        switch (cmd) {
+        case RAW1394_IOC_ISO_XMIT_START:{
+                        int args[2];
+
+                        if (copy_from_user(&args[0], argp, sizeof(args)))
+                                return -EFAULT;
+                        return hpsb_iso_xmit_start(fi->iso_handle,
+                                                   args[0], args[1]);
                 }
-                break;
+        case RAW1394_IOC_ISO_XMIT_SYNC:
+                return hpsb_iso_xmit_sync(fi->iso_handle);
+        case RAW1394_IOC_ISO_XMIT_RECV_STOP:
+                hpsb_iso_stop(fi->iso_handle);
+                return 0;
+        case RAW1394_IOC_ISO_GET_STATUS:
+                return raw1394_iso_get_status(fi, argp);
+        case RAW1394_IOC_ISO_XMIT_PACKETS:
+                return raw1394_iso_send_packets(fi, argp);
+        case RAW1394_IOC_ISO_SHUTDOWN:
+                raw1394_iso_shutdown(fi);
+                return 0;
+        case RAW1394_IOC_ISO_QUEUE_ACTIVITY:
+                queue_rawiso_event(fi);
+                return 0;
         default:
-                break;
+                return -EINVAL;
         }
+}
+
+/* ioctl is only used for rawiso operations */
+static long raw1394_ioctl(struct file *file, unsigned int cmd,
+                          unsigned long arg)
+{
+        struct file_info *fi = file->private_data;
+        void __user *argp = (void __user *)arg;
+        long ret;
 
         /* state-independent commands */
         switch(cmd) {
@@ -2661,18 +2665,25 @@ static long do_raw1394_ioctl(struct file *file, unsigned int cmd,
                 break;
         }
 
-        return -EINVAL;
-}
+        mutex_lock(&fi->state_mutex);
 
-static long raw1394_ioctl(struct file *file, unsigned int cmd,
-                                                        unsigned long arg)
-{
-        struct file_info *fi = file->private_data;
-        long ret;
+        switch (fi->iso_state) {
+        case RAW1394_ISO_INACTIVE:
+                ret = raw1394_ioctl_inactive(fi, cmd, argp);
+                break;
+        case RAW1394_ISO_RECV:
+                ret = raw1394_ioctl_recv(fi, cmd, arg);
+                break;
+        case RAW1394_ISO_XMIT:
+                ret = raw1394_ioctl_xmit(fi, cmd, argp);
+                break;
+        default:
+                ret = -EINVAL;
+                break;
+        }
 
-        mutex_lock(&fi->state_mutex);
-        ret = do_raw1394_ioctl(file, cmd, arg);
         mutex_unlock(&fi->state_mutex);
+
         return ret;
 }
 
@@ -2710,7 +2721,7 @@ static long raw1394_iso_xmit_recv_packets32(struct file *file, unsigned int cmd,
             !copy_from_user(&infos32, &arg->infos, sizeof infos32)) {
                 infos = compat_ptr(infos32);
                 if (!copy_to_user(&dst->infos, &infos, sizeof infos))
-                        err = do_raw1394_ioctl(file, cmd, (unsigned long)dst);
+                        err = raw1394_ioctl(file, cmd, (unsigned long)dst);
         }
         return err;
 }
@@ -2734,7 +2745,6 @@ static long raw1394_compat_ioctl(struct file *file,
         void __user *argp = (void __user *)arg;
         long err;
 
-        mutex_lock(&fi->state_mutex);
         switch (cmd) {
         /* These requests have same format as long as 'int' has same size. */
         case RAW1394_IOC_ISO_RECV_INIT:
@@ -2751,7 +2761,7 @@ static long raw1394_compat_ioctl(struct file *file,
         case RAW1394_IOC_ISO_GET_STATUS:
         case RAW1394_IOC_ISO_SHUTDOWN:
         case RAW1394_IOC_ISO_QUEUE_ACTIVITY:
-                err = do_raw1394_ioctl(file, cmd, arg);
+                err = raw1394_ioctl(file, cmd, arg);
                 break;
         /* These request have different format. */
         case RAW1394_IOC_ISO_RECV_PACKETS32:
@@ -2767,7 +2777,6 @@ static long raw1394_compat_ioctl(struct file *file,
                 err = -EINVAL;
                 break;
         }
-        mutex_unlock(&fi->state_mutex);
 
         return err;
 }