ref: 57f8b3d1acf273a88568c49d0b83b6863485b9e0
dir: /sys/src/cmd/cwfs/iobuf.c/
#include "all.h" #include "io.h" extern uint nhiob; extern Hiob *hiob; Iobuf* getbuf(Device *d, Off addr, int flag) { Iobuf *p, *s; Hiob *hp; Off h; if(chatty > 1) fprint(2, "getbuf %Z(%lld) f=%x\n", d, (Wideoff)addr, flag); h = addr + (Off)(uintptr)d*1009; if(h < 0) h = ~h; h %= nhiob; hp = &hiob[h]; loop: lock(hp); /* * look for it in the active list */ s = hp->link; for(p=s;;) { if(p->addr == addr && p->dev == d) { if(p != s) { p->back->fore = p->fore; p->fore->back = p->back; p->fore = s; p->back = s->back; s->back = p; p->back->fore = p; hp->link = p; } unlock(hp); qlock(p); if(p->addr != addr || p->dev != d || iobufmap(p) == 0) { qunlock(p); goto loop; } p->flags |= flag; return p; } p = p->fore; if(p == s) break; } if(flag & Bprobe) { unlock(hp); return 0; } /* * not found * take oldest unlocked entry in this queue */ xloop: p = s->back; if(!canqlock(p)) { if(p == hp->link) { unlock(hp); fprint(2, "iobuf all locked\n"); goto loop; } s = p; goto xloop; } /* * its dangerous to flush the pseudo * devices since they recursively call * getbuf/putbuf. deadlock! */ if(p->flags & Bres) { qunlock(p); if(p == hp->link) { unlock(hp); fprint(2, "iobuf all reserved\n"); goto loop; } s = p; goto xloop; } if(p->flags & Bmod) { unlock(hp); if(iobufmap(p)) { if(!devwrite(p->dev, p->addr, p->iobuf)) p->flags &= ~(Bimm|Bmod); iobufunmap(p); } qunlock(p); goto loop; } hp->link = p; p->addr = addr; p->dev = d; p->flags = flag; unlock(hp); if(iobufmap(p)) if(flag & Brd) { if(!devread(p->dev, p->addr, p->iobuf)) return p; iobufunmap(p); } else return p; else fprint(2, "iobuf cant map buffer %Z(%lld)\n", p->dev, (Wideoff)p->addr); p->flags = 0; p->dev = devnone; p->addr = -1; qunlock(p); return 0; } /* * syncblock tries to put out a block per hashline * returns 0 all done, * returns 1 if it missed something */ int syncblock(void) { Iobuf *p, *s, *q; Hiob *hp; long h; int flag; flag = 0; for(h=0; h<nhiob; h++) { q = 0; hp = &hiob[h]; lock(hp); s = hp->link; for(p=s;;) { if(p->flags & Bmod) { if(q) flag = 1; /* more than 1 mod/line */ q = p; } p = p->fore; if(p == s) break; } unlock(hp); if(q) { if(!canqlock(q)) { flag = 1; /* missed -- was locked */ continue; } if(!(q->flags & Bmod)) { qunlock(q); continue; } if(iobufmap(q)) { if(!devwrite(q->dev, q->addr, q->iobuf)) q->flags &= ~(Bmod|Bimm); iobufunmap(q); } else flag = 1; qunlock(q); } } return flag; } void sync(char *reason) { long i; if(chatty) fprint(2, "sync: %s\n", reason); for(i=10*nhiob; i>0; i--) if(!syncblock()) return; } void putbuf(Iobuf *p) { if(canqlock(p)) fprint(2, "buffer not locked %Z(%lld)\n", p->dev, (Wideoff)p->addr); if(p->flags & Bimm) { if(!(p->flags & Bmod)) fprint(2, "imm and no mod %Z(%lld)\n", p->dev, (Wideoff)p->addr); if(!devwrite(p->dev, p->addr, p->iobuf)) p->flags &= ~(Bmod|Bimm); } iobufunmap(p); qunlock(p); } int checktag(Iobuf *p, int tag, Off qpath) { Tag *t; uintptr pc; t = (Tag*)(p->iobuf+BUFSIZE); if(tag != t->tag || qpath != QPNONE && qpath != t->path){ pc = getcallerpc(&p); if(qpath == QPNONE){ fprint(2, "checktag pc=%p %Z(%llux) tag/path=%G/%llud; expected %G\n", pc, p->dev, (Wideoff)p->addr, t->tag, (Wideoff)t->path, tag); } else { fprint(2, "checktag pc=%p %Z(%llux) tag/path=%G/%llud; expected %G/%llud\n", pc, p->dev, (Wideoff)p->addr, t->tag, (Wideoff)t->path, tag, (Wideoff)qpath); } return 1; } return 0; } void settag(Iobuf *p, int tag, Off qpath) { Tag *t; t = (Tag*)(p->iobuf+BUFSIZE); t->tag = tag; if(qpath != QPNONE) t->path = qpath; p->flags |= Bmod; } int qlmatch(QLock *q1, QLock *q2) { return q1 == q2; } int iobufql(QLock *q) { Iobuf *p, *s; Hiob *hp; long h; for(h=0; h<nhiob; h++) { hp = &hiob[h]; lock(hp); s = hp->link; for(p=s;;) { if(qlmatch(q, p)) { unlock(hp); return 1; } p = p->fore; if(p == s) break; } unlock(hp); } return 0; }