ref: 523c33bb6f61260c14ec12ea25b0bba89ba4e856
parent: c8ed49da608c1c99ec6dab7a6e9bbc26f3f05277
author: cinap_lenrek <cinap_lenrek@felloff.net>
date: Mon Dec 15 01:28:27 EST 2014
kernel: minor changes to mount cache change page cache ids (bid) to uintptr so we use the full address space of Page.daddr. make maxcache offset check consistent in cread(). use consistent types in cupdate() and simplify with goto. make internal functions static. use nil instead of 0 for pointers.
--- a/sys/src/9/port/cache.c
+++ b/sys/src/9/port/cache.c
@@ -16,7 +16,7 @@
typedef struct Extent Extent;
struct Extent
{- int bid;
+ uintptr bid;
ulong start;
int len;
Page *cache;
@@ -40,7 +40,7 @@
struct Cache
{Lock;
- int pgno;
+ uintptr pgno;
Mntcache *head;
Mntcache *tail;
Mntcache *hash[NHASH];
@@ -59,7 +59,7 @@
static Cache cache;
static Ecache ecache;
-static int maxcache = MAXCACHE;
+static ulong maxcache = MAXCACHE;
static void
extentfree(Extent* e)
@@ -89,16 +89,17 @@
ecache.head = e;
e++;
}
- ecache.free += NEXTENT;
ecache.total += NEXTENT;
+ ecache.free += NEXTENT;
}
e = ecache.head;
ecache.head = e->next;
- memset(e, 0, sizeof(Extent));
ecache.free--;
unlock(&ecache);
+ memset(e, 0, sizeof(Extent));
+
return e;
}
@@ -124,23 +125,23 @@
}
cache.tail = m;
- cache.tail->next = 0;
- cache.head->prev = 0;
+ cache.tail->next = nil;
+ cache.head->prev = nil;
fscache.notext = 1;
}
-Page*
+static Page*
cpage(Extent *e)
{/* Easy consistency check */
if(e->cache->daddr != e->bid)
- return 0;
+ return nil;
return lookpage(&fscache, e->bid);
}
-void
+static void
cnodata(Mntcache *m)
{Extent *e;
@@ -147,38 +148,38 @@
/*
* Invalidate all extent data
- * Image lru will waste the pages
+ * pagereclaim() will waste the pages
*/
- while(e = m->list){+ while((e = m->list) != nil){m->list = e->next;
extentfree(e);
}
}
-void
+static void
ctail(Mntcache *m)
{/* Unlink and send to the tail */
- if(m->prev)
+ if(m->prev != nil)
m->prev->next = m->next;
else
cache.head = m->next;
- if(m->next)
+ if(m->next != nil)
m->next->prev = m->prev;
else
cache.tail = m->prev;
- if(cache.tail) {+ if(cache.tail != nil) {m->prev = cache.tail;
cache.tail->next = m;
- m->next = 0;
+ m->next = nil;
cache.tail = m;
}
else {cache.head = m;
cache.tail = m;
- m->prev = 0;
- m->next = 0;
+ m->prev = nil;
+ m->next = nil;
}
}
@@ -188,11 +189,11 @@
{Mntcache *m;
- for(m = cache.hash[c->qid.path%NHASH]; m; m = m->hash)
+ for(m = cache.hash[c->qid.path%NHASH]; m != nil; m = m->hash)
if(eqchantdqid(c, m->type, m->dev, m->qid, skipvers) && c->qid.type == m->qid.type)
return m;
- return 0;
+ return nil;
}
void
@@ -202,13 +203,13 @@
/* directories aren't cacheable and append-only files confuse us */
if(c->qid.type&(QTDIR|QTAPPEND)){- c->mcp = 0;
+ c->mcp = nil;
return;
}
lock(&cache);
m = clookup(c, 1);
- if(m == 0)
+ if(m == nil)
m = cache.head;
else if(m->qid.vers == c->qid.vers) {ctail(m);
@@ -219,7 +220,7 @@
ctail(m);
l = &cache.hash[m->qid.path%NHASH];
- for(f = *l; f; f = f->hash) {+ for(f = *l; f != nil; f = f->hash) { if(f == m) {*l = m->hash;
break;
@@ -232,7 +233,7 @@
qlock(m);
lock(&cache);
f = clookup(c, 0);
- if(f != 0) {+ if(f != nil) {/*
* someone got there first while cache lock
* was released and added a updated Mntcache
@@ -266,14 +267,14 @@
Mntcache *m;
m = c->mcp;
- if(m) {+ if(m != nil) {qlock(m);
if(eqchantdqid(c, m->type, m->dev, m->qid, 0) && c->qid.type == m->qid.type)
return m;
- c->mcp = 0;
+ c->mcp = nil;
qunlock(m);
}
- return 0;
+ return nil;
}
int
@@ -286,34 +287,33 @@
int o, l, total;
ulong offset;
- if(off+len > maxcache)
+ if(off >= maxcache || len <= 0)
return 0;
m = ccache(c);
- if(m == 0)
+ if(m == nil)
return 0;
offset = off;
t = &m->list;
- for(e = *t; e; e = e->next) {+ for(e = *t; e != nil; e = e->next) {if(offset >= e->start && offset < e->start+e->len)
break;
t = &e->next;
}
- if(e == 0) {+ if(e == nil) {qunlock(m);
return 0;
}
total = 0;
- while(len) {+ while(len > 0) {p = cpage(e);
- if(p == 0) {+ if(p == nil) {*t = e->next;
extentfree(e);
- qunlock(m);
- return total;
+ break;
}
o = offset - e->start;
@@ -342,7 +342,7 @@
total += l;
t = &e->next;
e = e->next;
- if(e == 0 || e->start != offset)
+ if(e == nil || e->start != offset)
break;
}
@@ -350,7 +350,7 @@
return total;
}
-Extent*
+static Extent*
cchain(uchar *buf, ulong offset, int len, Extent **tail)
{int l;
@@ -358,16 +358,16 @@
KMap *k;
Extent *e, *start, **t;
- start = 0;
- *tail = 0;
+ start = nil;
+ *tail = nil;
t = &start;
- while(len) {+ while(len > 0) {e = extentalloc();
- if(e == 0)
+ if(e == nil)
break;
p = auxpage();
- if(p == 0) {+ if(p == nil) {extentfree(e);
break;
}
@@ -417,7 +417,7 @@
return start;
}
-int
+static int
cpgmove(Extent *e, uchar *buf, int boff, int len)
{Page *p;
@@ -424,7 +424,7 @@
KMap *k;
p = cpage(e);
- if(p == 0)
+ if(p == nil)
return 0;
k = kmap(p);
@@ -445,17 +445,17 @@
void
cupdate(Chan *c, uchar *buf, int len, vlong off)
{+ int o;
Mntcache *m;
Extent *tail;
Extent *e, *f, *p;
- int o, ee, eblock;
- ulong offset;
+ ulong offset, eblock, ee;
- if(off > maxcache || len == 0)
+ if(off >= maxcache || len <= 0)
return;
m = ccache(c);
- if(m == 0)
+ if(m == nil)
return;
/*
@@ -462,8 +462,8 @@
* Find the insertion point
*/
offset = off;
- p = 0;
- for(f = m->list; f; f = f->next) {+ p = nil;
+ for(f = m->list; f != nil; f = f->next) {if(f->start > offset)
break;
p = f;
@@ -471,22 +471,19 @@
/* trim if there is a successor */
eblock = offset+len;
- if(f != 0 && eblock > f->start) {+ if(f != nil && eblock > f->start) {len -= (eblock - f->start);
- if(len <= 0) {- qunlock(m);
- return;
- }
+ if(len <= 0)
+ goto out;
}
- if(p == 0) { /* at the head */+ if(p == nil) { /* at the head */e = cchain(buf, offset, len, &tail);
- if(e != 0) {+ if(e != nil) {m->list = e;
tail->next = f;
}
- qunlock(m);
- return;
+ goto out;
}
/* trim to the predecessor */
@@ -494,10 +491,8 @@
if(offset < ee) {o = ee - offset;
len -= o;
- if(len <= 0) {- qunlock(m);
- return;
- }
+ if(len <= 0)
+ goto out;
buf += o;
offset += o;
}
@@ -513,20 +508,20 @@
len -= o;
offset += o;
if(len <= 0) {- if(f && p->start + p->len > f->start)
+ if(f != nil && p->start + p->len > f->start)
print("CACHE: p->start=%uld p->len=%d f->start=%uld\n",p->start, p->len, f->start);
- qunlock(m);
- return;
+ goto out;
}
}
}
e = cchain(buf, offset, len, &tail);
- if(e != 0) {+ if(e != nil) {p->next = e;
tail->next = f;
}
+out:
qunlock(m);
}
@@ -535,15 +530,14 @@
{int o, eo;
Mntcache *m;
- ulong eblock, ee;
Extent *p, *f, *e, *tail;
- ulong offset;
+ ulong offset, eblock, ee;
- if(off > maxcache || len == 0)
+ if(off >= maxcache || len <= 0)
return;
m = ccache(c);
- if(m == 0)
+ if(m == nil)
return;
offset = off;
@@ -550,14 +544,14 @@
m->qid.vers++;
c->qid.vers++;
- p = 0;
- for(f = m->list; f; f = f->next) {+ p = nil;
+ for(f = m->list; f != nil; f = f->next) {if(f->start >= offset)
break;
p = f;
}
- if(p != 0) {+ if(p != nil) {ee = p->start+p->len;
eo = offset - p->start;
/* pack in predecessor if there is space */
@@ -577,7 +571,7 @@
/* free the overlap -- it's a rare case */
eblock = offset+len;
- while(f && f->start < eblock) {+ while(f != nil && f->start < eblock) {e = f->next;
extentfree(f);
f = e;
@@ -585,12 +579,12 @@
/* link the block (if any) into the middle */
e = cchain(buf, offset, len, &tail);
- if(e != 0) {+ if(e != nil) {tail->next = f;
f = e;
}
- if(p == 0)
+ if(p == nil)
m->list = f;
else
p->next = f;