- Lock down the ``module'' structure by adding an SX lock that is used by

  all the global bits of ``module'' data.  This commit adds a few generic
  macros, MOD_SLOCK, MOD_XLOCK, etc., that are meant to be used as ways
  of accessing the SX lock.  It is also the first step in helping to lock
  down the kernel linker and module systems.

Reviewed by: jhb, jake, smp@

1 files changed, 8 insertions, 7 deletions

diff --git a/sys/kern/kern_linker.c b/sys/kern/kern_linker.c
index 37c8605..d83e005 100644
--- a/sys/kern/kern_linker.c
+++ b/sys/kern/kern_linker.c
@@ -37,6 +37,7 @@
 #include <sys/proc.h>
 #include <sys/lock.h>
 #include <sys/mutex.h>
+#include <sys/sx.h>
 #include <sys/module.h>
 #include <sys/linker.h>
 #include <sys/fcntl.h>
@@ -45,7 +46,6 @@
 #include <sys/vnode.h>
 #include <sys/sysctl.h>
 
-
 #include "linker_if.h"
 
 #ifdef KLD_DEBUG
@@ -274,11 +274,6 @@ linker_file_register_modules(linker_file_t lf)
 		moddata = (*mdp)->md_data;
 		KLD_DPF(FILE, ("Registering module %s in %s\n",
 		    moddata->name, lf->filename));
-		if (module_lookupbyname(moddata->name) != NULL) {
-			printf("Warning: module %s already exists\n",
-			    moddata->name);
-			continue;	/* or return a error ? */
-		}
 		error = module_register(moddata, lf);
 		if (error)
 			printf("Module %s failed to register: %d\n",
@@ -447,8 +442,10 @@ linker_file_unload(linker_file_t file)
 		/*
 		 * Inform any modules associated with this file.
 		 */
+		MOD_XLOCK;
 		for (mod = TAILQ_FIRST(&file->modules); mod; mod = next) {
 			next = module_getfnext(mod);
+			MOD_XUNLOCK;
 
 			/*
 			 * Give the module a chance to veto the unload.
@@ -458,9 +455,11 @@ linker_file_unload(linker_file_t file)
 				    " vetoes unload\n", mod));
 				lockmgr(&lock, LK_RELEASE, 0, curthread);
 				goto out;
-			}
+			} else
+				MOD_XLOCK;
 			module_release(mod);
 		}
+		MOD_XUNLOCK;
 	}
 	file->refs--;
 	if (file->refs > 0) {
@@ -900,11 +899,13 @@ kldfirstmod(struct thread *td, struct kldfirstmod_args *uap)
 	mtx_lock(&Giant);
 	lf = linker_find_file_by_id(SCARG(uap, fileid));
 	if (lf) {
+		MOD_SLOCK;
 		mp = TAILQ_FIRST(&lf->modules);
 		if (mp != NULL)
 			td->td_retval[0] = module_getid(mp);
 		else
 			td->td_retval[0] = 0;
+		MOD_SUNLOCK;
 	} else
 		error = ENOENT;
 	mtx_unlock(&Giant);