9os

commit 57efc95750bc7852b06c67a2c40dec9334b8df11
parent 6c78a717a2e6cde7c0a85e2e30fc7a58c938dd9b
Author: Roberto E. Vargas Caballero <roberto.vargas@midokura.com>
Date:   Fri, 18 Nov 2022 19:20:06 +0100

os9: Fix memory allocator

There were several problems in the calculation of the space used and
after moving to a list of pages the allocb() interface didn't make
sense anymore.

Diffstat:
M
include/os9/os9.h
 | 
2
+-
M
src/os9/alloc.c
 | 
19
++++++++++---------
M
src/os9/proc.c
 | 
12
++++++------

3 files changed, 17 insertions(+), 16 deletions(-)
diff --git a/include/os9/os9.h b/include/os9/os9.h
@@ -255,7 +255,7 @@ extern void unlocktask(Task *);
 
 /* alloc.c */
 extern void *alloc(size_t);
-extern void *allocb(int);
+extern void *allocb(void);
 extern void freeb(void *);
 extern void ialloc(void);
 
diff --git a/src/os9/alloc.c b/src/os9/alloc.c
@@ -14,6 +14,8 @@ struct {
 	mutex_t m;
 } bufpool;
 
+static union bucket *heap;
+
 void
 freeb(void *bp)
 {
@@ -30,7 +32,7 @@ freeb(void *bp)
 }
 
 void *
-allocb(int n)
+allocb(void)
 {
 	union bucket *bp = NULL;
 
@@ -51,9 +53,8 @@ alloc(size_t size)
 {
 	size_t n;
 	static size_t used;
-	static union bucket *heap;
 	static mutex_t m;
-	union bucket  *bp = NULL;
+	union bucket  *bp;
 
 	if (size == 0) {
 		errno = EINVAL;
@@ -61,16 +62,14 @@ alloc(size_t size)
 	}
 
 	lock(&m);
-	if (!heap)
-		heap = allocb(HEAPSIZ);
-
 	n = (size-1) / sizeof(union bucket) + 1;
 	size = n * sizeof(union bucket);
 
-	if (used > SIZE_MAX - size) {
+	if (used > PAGESIZE*HEAPSIZ - size) {
+		bp = NULL;
 		errno = ENOMEM;
 	} else {
-		bp = heap + used;
+		bp = heap + n;
 		used += size;
 	}
 	unlock(&m);
@@ -84,8 +83,10 @@ ialloc(void)
 	int i;
 	union bucket *bp, *prev;
 
+	heap = buffertab;
+
 	prev = NULL;
-	for (i = 0; i < NR_BUFFERS; i++) {
+	for (i = HEAPSIZ; i < NR_BUFFERS; i++) {
 		bp = (union bucket *) buffertab[i];
 		bp->next = prev;
 		prev = bp;
diff --git a/src/os9/proc.c b/src/os9/proc.c
@@ -130,13 +130,13 @@ mapseg(Map *mp)
 	n =  (mp->siz + PAGESIZE-1)/PAGESIZE;
 	va = mp->va;
 	pa = mp->pa;
-	if (pa == -1) {
-		if ((bp = allocb(n)) == NULL)
-			return -1;
-		pa = (phyaddr_t) PMEM(bp);
-	}
-
 	for (i = 0; i < n; i++) {
+		if (mp->pa == -1) {
+			if ((bp = allocb()) == NULL)
+				return -1;
+			pa = (phyaddr_t) PMEM(bp);
+		}
+
 		if (vmap(pa, va, mp->perm) < 0) {
 			freeb(bp);
 			return -1;