Module Name: src
Committed By: jdolecek
Date: Tue Apr 7 15:43:42 UTC 2020
Modified Files:
src/sys/arch/xen/xenbus: xenbus_dev.c
Log Message:
mostly convert to kmem_alloc()
doing this, remove check for failed allocation with KM_SLEEP, and make
sure to not hold mutex during the call
To generate a diff of this commit:
cvs rdiff -u -r1.15 -r1.16 src/sys/arch/xen/xenbus/xenbus_dev.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/xen/xenbus/xenbus_dev.c
diff -u src/sys/arch/xen/xenbus/xenbus_dev.c:1.15 src/sys/arch/xen/xenbus/xenbus_dev.c:1.16
--- src/sys/arch/xen/xenbus/xenbus_dev.c:1.15 Tue Apr 7 08:14:43 2020
+++ src/sys/arch/xen/xenbus/xenbus_dev.c Tue Apr 7 15:43:42 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: xenbus_dev.c,v 1.15 2020/04/07 08:14:43 jdolecek Exp $ */
+/* $NetBSD: xenbus_dev.c,v 1.16 2020/04/07 15:43:42 jdolecek Exp $ */
/*
* xenbus_dev.c
*
@@ -31,16 +31,16 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xenbus_dev.c,v 1.15 2020/04/07 08:14:43 jdolecek Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xenbus_dev.c,v 1.16 2020/04/07 15:43:42 jdolecek Exp $");
#include "opt_xen.h"
#include <sys/types.h>
#include <sys/null.h>
#include <sys/errno.h>
-#include <sys/malloc.h>
#include <sys/param.h>
#include <sys/proc.h>
+#include <sys/malloc.h>
#include <sys/systm.h>
#include <sys/dirent.h>
#include <sys/stat.h>
@@ -289,8 +289,7 @@ xenbus_dev_write(void *v)
err = xenbus_dev_request_and_reply(&xlwp->u.msg, &reply);
if (err == 0) {
if (xlwp->u.msg.type == XS_TRANSACTION_START) {
- trans = malloc(sizeof(*trans), M_DEVBUF,
- M_WAITOK);
+ trans = kmem_alloc(sizeof(*trans), KM_SLEEP);
trans->handle = (struct xenbus_transaction *)
strtoul(reply, NULL, 0);
SLIST_INSERT_HEAD(&xlwp->transactions,
@@ -308,7 +307,7 @@ xenbus_dev_write(void *v)
}
SLIST_REMOVE(&xlwp->transactions, trans,
xenbus_dev_transaction, trans_next);
- free(trans, M_DEVBUF);
+ kmem_free(trans, sizeof(*trans));
}
queue_reply(xlwp, (char *)&xlwp->u.msg,
sizeof(xlwp->u.msg));
@@ -348,37 +347,50 @@ xenbus_dev_open(void *v)
mutex_enter(&xenbus_dev_open_mtx);
u = kfs->kfs_v;
if (u == NULL) {
- u = malloc(sizeof(*u), M_DEVBUF, M_WAITOK);
- if (u == NULL) {
- mutex_exit(&xenbus_dev_open_mtx);
- return ENOMEM;
- }
- memset(u, 0, sizeof(*u));
+ mutex_exit(&xenbus_dev_open_mtx);
+
+ u = kmem_zalloc(sizeof(*u), KM_SLEEP);
SLIST_INIT(&u->lwps);
mutex_init(&u->mtx, MUTEX_DEFAULT, IPL_NONE);
- kfs->kfs_v = u;
+
+ mutex_enter(&xenbus_dev_open_mtx);
+ /*
+ * Must re-check if filled while waiting in alloc
+ * by some other lwp.
+ */
+ if (kfs->kfs_v) {
+ kmem_free(u, sizeof(*u));
+ u = kfs->kfs_v;
+ } else {
+ kfs->kfs_v = u;
+ }
};
- mutex_enter(&u->mtx);
mutex_exit(&xenbus_dev_open_mtx);
+
+ mutex_enter(&u->mtx);
SLIST_FOREACH(xlwp, &u->lwps, lwp_next) {
if (xlwp->lwp == curlwp) {
break;
}
}
if (xlwp == NULL) {
- xlwp = malloc(sizeof(*xlwp ), M_DEVBUF, M_WAITOK);
- if (xlwp == NULL) {
- mutex_exit(&u->mtx);
- return ENOMEM;
- }
- memset(xlwp, 0, sizeof(*xlwp));
+ mutex_exit(&u->mtx);
+
+ xlwp = kmem_zalloc(sizeof(*xlwp), KM_SLEEP);
xlwp->lwp = curlwp;
SLIST_INIT(&xlwp->transactions);
mutex_init(&xlwp->mtx, MUTEX_DEFAULT, IPL_NONE);
- SLIST_INSERT_HEAD(&u->lwps,
- xlwp, lwp_next);
+
+ mutex_enter(&u->mtx);
+ /*
+ * While alloc can block, this can't be re-entered with
+ * curlwp, so no need to re-check. Also the node can't
+ * be closed while we are blocked here.
+ */
+ SLIST_INSERT_HEAD(&u->lwps, xlwp, lwp_next);
}
mutex_exit(&u->mtx);
+
return 0;
}
@@ -415,7 +427,7 @@ xenbus_dev_close(void *v)
trans = SLIST_FIRST(&xlwp->transactions);
xenbus_transaction_end(trans->handle, 1);
SLIST_REMOVE_HEAD(&xlwp->transactions, trans_next);
- free(trans, M_DEVBUF);
+ kmem_free(trans, sizeof(*trans));
}
mutex_exit(&xlwp->mtx);
SLIST_REMOVE(&u->lwps, xlwp, xenbus_dev_lwp, lwp_next);
@@ -430,8 +442,8 @@ xenbus_dev_close(void *v)
mutex_destroy(&u->mtx);
kfs->kfs_v = NULL;
mutex_exit(&xenbus_dev_open_mtx);
- free(xlwp, M_DEVBUF);
- free(u, M_DEVBUF);
+ kmem_free(xlwp, sizeof(*xlwp));
+ kmem_free(u, sizeof(*u));
return 0;
}
