projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| f86df66c | 1 | /* ufs_disksubr.c 3.2 %G% */ |
| 200a8f27 BJ |
2 | |
| 3 | /* | |
| 4 | * generalized seek sort for disk | |
| 5 | */ | |
| 6 | ||
| 7 | #include "../h/param.h" | |
| 8 | #include "../h/systm.h" | |
| 9 | #include "../h/buf.h" | |
| 10 | ||
| 11 | #define b_cylin b_resid | |
| 12 | ||
| 13 | disksort(dp, bp) | |
| 14 | register struct buf *dp, *bp; | |
| 15 | { | |
| 16 | register struct buf *ap; | |
| 17 | struct buf *tp; | |
| 18 | ||
| 19 | ap = dp->b_actf; | |
| 20 | if(ap == NULL) { | |
| 21 | dp->b_actf = bp; | |
| 22 | dp->b_actl = bp; | |
| 23 | bp->av_forw = NULL; | |
| 24 | return; | |
| 25 | } | |
| 26 | tp = NULL; | |
| 27 | for(; ap != NULL; ap = ap->av_forw) { | |
| 28 | if ((bp->b_flags&B_READ) && (ap->b_flags&B_READ) == 0) { | |
| 29 | if (tp == NULL) | |
| 30 | tp = ap; | |
| 31 | break; | |
| 32 | } | |
| 33 | if ((bp->b_flags&B_READ) == 0 && (ap->b_flags&B_READ)) | |
| 34 | continue; | |
| 35 | if(ap->b_cylin <= bp->b_cylin) | |
| 36 | if(tp == NULL || ap->b_cylin >= tp->b_cylin) | |
| 37 | tp = ap; | |
| 38 | } | |
| 39 | if(tp == NULL) | |
| 40 | tp = dp->b_actl; | |
| 41 | bp->av_forw = tp->av_forw; | |
| 42 | tp->av_forw = bp; | |
| 43 | if(tp == dp->b_actl) | |
| 44 | dp->b_actl = bp; | |
| 45 | } |