diff options
| -rw-r--r-- | sys/vm/vm_mmap.c | 37 |
1 files changed, 33 insertions, 4 deletions
diff --git a/sys/vm/vm_mmap.c b/sys/vm/vm_mmap.c index cda3ee0..974fd00 100644 --- a/sys/vm/vm_mmap.c +++ b/sys/vm/vm_mmap.c @@ -38,7 +38,7 @@ * from: Utah $Hdr: vm_mmap.c 1.6 91/10/21$ * * @(#)vm_mmap.c 8.4 (Berkeley) 1/12/94 - * $Id: vm_mmap.c,v 1.90 1999/02/19 14:25:36 luoqi Exp $ + * $Id: vm_mmap.c,v 1.91 1999/03/01 20:42:16 alc Exp $ */ /* @@ -675,6 +675,7 @@ mincore(p, uap) register vm_map_entry_t current; vm_map_entry_t entry; int mincoreinfo; + unsigned int timestamp; /* * Make sure that the addresses presented are valid for user @@ -696,6 +697,8 @@ mincore(p, uap) pmap = vmspace_pmap(p->p_vmspace); vm_map_lock_read(map); +RestartScan: + timestamp = map->timestamp; if (!vm_map_lookup_entry(map, addr, &entry)) entry = entry->next; @@ -766,6 +769,12 @@ mincore(p, uap) } /* + * subyte may page fault. In case it needs to modify + * the map, we release the lock. + */ + vm_map_unlock_read(map); + + /* * calculate index into user supplied byte vector */ vecindex = OFF_TO_IDX(addr - first_addr); @@ -777,7 +786,6 @@ mincore(p, uap) while((lastvecindex + 1) < vecindex) { error = subyte( vec + lastvecindex, 0); if (error) { - vm_map_unlock_read(map); return (EFAULT); } ++lastvecindex; @@ -788,28 +796,49 @@ mincore(p, uap) */ error = subyte( vec + vecindex, mincoreinfo); if (error) { - vm_map_unlock_read(map); return (EFAULT); } + + /* + * If the map has changed, due to the subyte, the previous + * output may be invalid. + */ + vm_map_lock_read(map); + if (timestamp != map->timestamp) + goto RestartScan; + lastvecindex = vecindex; addr += PAGE_SIZE; } } /* + * subyte may page fault. In case it needs to modify + * the map, we release the lock. + */ + vm_map_unlock_read(map); + + /* * Zero the last entries in the byte vector. */ vecindex = OFF_TO_IDX(end - first_addr); while((lastvecindex + 1) < vecindex) { error = subyte( vec + lastvecindex, 0); if (error) { - vm_map_unlock_read(map); return (EFAULT); } ++lastvecindex; } + /* + * If the map has changed, due to the subyte, the previous + * output may be invalid. + */ + vm_map_lock_read(map); + if (timestamp != map->timestamp) + goto RestartScan; vm_map_unlock_read(map); + return (0); } |
