From 2986c1181194bb87cd24650e1e5ea67409600621 Mon Sep 17 00:00:00 2001
From: Ben Gras <ben@minix3.org>
Date: Mon, 3 Oct 2005 14:17:33 +0000
Subject: [PATCH] DEV_UNMAP devctl() FSDEVUNMAP svrctl()

---
 servers/fs/dmap.c | 16 +++++++++++++---
 servers/fs/misc.c | 12 ++++++++++++
 2 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/servers/fs/dmap.c b/servers/fs/dmap.c
index c177258ac..73a57fe87 100644
--- a/servers/fs/dmap.c
+++ b/servers/fs/dmap.c
@@ -68,7 +68,7 @@ PUBLIC int do_devctl()
       result = map_driver(m_in.dev_nr, m_in.driver_nr, m_in.dev_style);
       break;
   case DEV_UNMAP:
-      result = ENOSYS;
+      result = map_driver(m_in.dev_nr, NONE, 0);
       break;
   default:
       result = EINVAL;
@@ -86,20 +86,30 @@ int style;			/* style of the device */
 {
 /* Set a new device driver mapping in the dmap table. Given that correct 
  * arguments are given, this only works if the entry is mutable and the 
- * current driver is not busy. 
+ * current driver is not busy.  If the proc_nr is set to NONE, we're supposed
+ * to unmap it.
+ *
  * Normal error codes are returned so that this function can be used from
  * a system call that tries to dynamically install a new driver.
  */
   struct dmap *dp;
 
   /* Get pointer to device entry in the dmap table. */
-  if (major >= NR_DEVICES) return(ENODEV);
+  if (major < 0 || major >= NR_DEVICES) return(ENODEV);
   dp = &dmap[major];		
 	
   /* See if updating the entry is allowed. */
   if (! (dp->dmap_flags & DMAP_MUTABLE))  return(EPERM);
   if (dp->dmap_flags & DMAP_BUSY)  return(EBUSY);
 
+  /* Check if we're supposed to unmap it. */
+ if(proc_nr == NONE) {
+	dp->dmap_opcl = no_dev;
+	dp->dmap_io = 0;
+	dp->dmap_driver = 0;
+	return(OK);
+  }
+
   /* Check process number of new driver. */
   if (! isokprocnr(proc_nr))  return(EINVAL);
 
diff --git a/servers/fs/misc.c b/servers/fs/misc.c
index 1c1538631..b4abdb57f 100644
--- a/servers/fs/misc.c
+++ b/servers/fs/misc.c
@@ -439,6 +439,18 @@ PUBLIC int do_svrctl()
 	r=map_driver(major, who, device.style);
 	return(r);
   }
+  case FSDEVUNMAP: {
+	struct fsdevunmap fdu;
+	int r, major;
+	/* Try to copy request structure to FS. */
+	if ((r = sys_datacopy(who, (vir_bytes) m_in.svrctl_argp,
+		FS_PROC_NR, (vir_bytes) &fdu,
+		(phys_bytes) sizeof(fdu))) != OK) 
+	    return(r);
+	major = (fdu.dev >> MAJOR) & BYTE;
+	r=map_driver(major, NONE, 0);
+	return(r);
+  }
   default:
 	return(EINVAL);
   }
-- 
2.44.0