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Add synchronization. Eliminate the acquisition and release of Giant.

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Reviewed by: tegge
This commit is contained in:
Alan Cox 2007-04-23 06:12:24 +00:00
parent b298baf298
commit cf75c506db
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=168968
1 changed files with 47 additions and 23 deletions
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70
sys/fs/procfs/procfs_map.c
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@ -42,6 +42,7 @@
#include <sys/lock.h>
#include <sys/filedesc.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/uio.h>
@ -81,12 +82,13 @@ int
procfs_doprocmap(PFS_FILL_ARGS)
{
int len;
int error;
int error, vfslocked;
vm_map_t map = &p->p_vmspace->vm_map;
pmap_t pmap = vmspace_pmap(p->p_vmspace);
vm_map_entry_t entry;
vm_map_entry_t entry, tmp_entry;
struct vnode *vp;
char mebuffer[MEBUFFERSIZE];
char *fullpath, *freepath;
unsigned int last_timestamp;
#ifdef COMPAT_IA32
int wrap32 = 0;
#endif
@ -111,11 +113,7 @@ procfs_doprocmap(PFS_FILL_ARGS)
}
#endif
mtx_lock(&Giant);
error = 0;
if (map != &curthread->td_proc->p_vmspace->vm_map)
vm_map_lock_read(map);
vm_map_lock_read(map);
for (entry = map->header.next;
((uio->uio_resid > 0) && (entry != &map->header));
entry = entry->next) {
@ -128,22 +126,29 @@ procfs_doprocmap(PFS_FILL_ARGS)
if (entry->eflags & MAP_ENTRY_IS_SUB_MAP)
continue;
privateresident = 0;
obj = entry->object.vm_object;
if (obj && (obj->shadow_count == 1))
privateresident = obj->resident_page_count;
else
privateresident = 0;
if (obj != NULL) {
VM_OBJECT_LOCK(obj);
if (obj->shadow_count == 1)
privateresident = obj->resident_page_count;
}
resident = 0;
addr = entry->start;
while (addr < entry->end) {
if (pmap_extract( pmap, addr))
if (pmap_extract(map->pmap, addr))
resident++;
addr += PAGE_SIZE;
}
for (lobj = tobj = obj; tobj; tobj = tobj->backing_object)
for (lobj = tobj = obj; tobj; tobj = tobj->backing_object) {
if (tobj != obj)
VM_OBJECT_LOCK(tobj);
if (lobj != obj)
VM_OBJECT_UNLOCK(lobj);
lobj = tobj;
}
freepath = NULL;
fullpath = "-";
@ -152,25 +157,36 @@ procfs_doprocmap(PFS_FILL_ARGS)
default:
case OBJT_DEFAULT:
type = "default";
vp = NULL;
break;
case OBJT_VNODE:
type = "vnode";
vn_fullpath(td,
(struct vnode *)lobj->handle,
&fullpath,
&freepath);
vp = lobj->handle;
vref(vp);
break;
case OBJT_SWAP:
type = "swap";
vp = NULL;
break;
case OBJT_DEVICE:
type = "device";
vp = NULL;
break;
}
if (lobj != obj)
VM_OBJECT_UNLOCK(lobj);
flags = obj->flags;
ref_count = obj->ref_count;
shadow_count = obj->shadow_count;
VM_OBJECT_UNLOCK(obj);
if (vp != NULL) {
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
vn_fullpath(td, vp, &fullpath, &freepath);
vput(vp);
VFS_UNLOCK_GIANT(vfslocked);
}
} else {
type = "none";
flags = 0;
@ -207,14 +223,22 @@ procfs_doprocmap(PFS_FILL_ARGS)
error = EFBIG;
break;
}
last_timestamp = map->timestamp;
vm_map_unlock_read(map);
error = uiomove(mebuffer, len, uio);
vm_map_lock_read(map);
if (error)
break;
if (last_timestamp + 1 != map->timestamp) {
/*
* Look again for the entry because the map was
* modified while it was unlocked. Specifically,
* the entry may have been clipped, merged, or deleted.
*/
vm_map_lookup_entry(map, addr - 1, &tmp_entry);
entry = tmp_entry;
}
}
if (map != &curthread->td_proc->p_vmspace->vm_map)
vm_map_unlock_read(map);
mtx_unlock(&Giant);
vm_map_unlock_read(map);
return (error);
}