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Changed the way the vnode cache is set - it's now cleaner and can no longer

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allocate a cache twice. Now handles resource shortages gracefully.
Added small description to _vm_map_file().
Minor other cleanup.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@8816 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler 2004-09-03 14:09:26 +00:00
parent 36ce5c0164
commit 2f1cbcf862
1 changed files with 68 additions and 57 deletions
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125
src/kernel/core/vm/vm.c
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@ -497,8 +497,8 @@ insert_area(vm_address_space *addressSpace, void **_address,
// a ref to the cache holding this store must be held before entering here
static int
map_backing_store(vm_address_space *aspace, vm_store *store, void **vaddr,
off_t offset, addr_t size, int addr_type, int wiring, int lock,
map_backing_store(vm_address_space *aspace, vm_store *store, void **_virtualAddress,
off_t offset, addr_t size, int addressSpec, int wiring, int lock,
int mapping, vm_region **_region, const char *region_name)
{
vm_cache *cache;
@ -511,7 +511,7 @@ map_backing_store(vm_address_space *aspace, vm_store *store, void **vaddr,
int err;
TRACE(("map_backing_store: aspace %p, store %p, *vaddr %p, offset 0x%Lx, size %lu, addr_type %d, wiring %d, lock %d, _region %p, region_name '%s'\n",
aspace, store, *vaddr, offset, size, addr_type, wiring, lock, _region, region_name));
aspace, store, *_virtualAddress, offset, size, addressSpec, wiring, lock, _region, region_name));
region = _vm_create_region_struct(aspace, region_name, wiring, lock);
if (!region)
@ -591,7 +591,7 @@ map_backing_store(vm_address_space *aspace, vm_store *store, void **vaddr,
goto err1b;
}
err = insert_area(aspace, vaddr, addr_type, size, region);
err = insert_area(aspace, _virtualAddress, addressSpec, size, region);
if (err < B_OK)
goto err1b;
@ -1006,79 +1006,90 @@ vm_create_null_region(aspace_id aid, char *name, void **address, int addr_type,
}
static region_id
_vm_map_file(aspace_id aid, char *name, void **address, int addr_type,
addr_t size, int lock, int mapping, const char *path, off_t offset, bool kernel)
status_t
vm_create_vnode_cache(void *vnode, void **_cache)
{
vm_region *region;
vm_cache *cache;
vm_cache_ref *cache_ref;
vm_cache *cache;
vm_store *store;
void *v;
// addr_t map_offset;
int err;
// create a vnode store object
store = vm_store_create_vnode(vnode);
if (store == NULL) {
dprintf("vm_create_vnode_cache: couldn't create vnode store\n");
return B_NO_MEMORY;
}
cache = vm_cache_create(store);
if (cache == NULL) {
dprintf("vm_create_vnode_cache: vm_cache_create returned NULL\n");
return B_NO_MEMORY;
}
cache_ref = vm_cache_ref_create(cache);
if (cache_ref == NULL) {
dprintf("vm_create_vnode_cache: vm_cache_ref_create returned NULL\n");
return B_NO_MEMORY;
}
// acquire the cache ref once to represent the ref that the vnode will have
// this is one of the only places where we dont want to ref to ripple down to the store
vm_cache_acquire_ref(cache_ref, false);
*_cache = cache_ref;
return B_OK;
}
/** Will map the file at the path specified by \a name to an area in memory.
* The file will be mirrored beginning at the specified \a offset. The \a offset
* and \a size arguments have to be page aligned.
*/
static region_id
_vm_map_file(aspace_id aid, char *name, void **_address, uint32 addressSpec,
size_t size, int lock, int mapping, const char *path, off_t offset, bool kernel)
{
vm_cache_ref *cache_ref;
vm_region *area;
void *vnode;
status_t status;
vm_address_space *aspace = vm_get_aspace_by_id(aid);
if (aspace == NULL)
return ERR_VM_INVALID_ASPACE;
offset = ROUNDOWN(offset, PAGE_SIZE);
offset = ROUNDOWN(offset, B_PAGE_SIZE);
size = PAGE_ALIGN(size);
restart:
// get the vnode for the object, this also grabs a ref to it
err = vfs_get_vnode_from_path(path, kernel, &v);
if (err < 0) {
vm_put_aspace(aspace);
return err;
}
status = vfs_get_vnode_from_path(path, kernel, &vnode);
if (status < B_OK)
goto err1;
cache_ref = vfs_get_cache_ptr(v);
if (!cache_ref) {
// create a vnode store object
store = vm_store_create_vnode(v);
if (store == NULL)
panic("vm_map_file: couldn't create vnode store");
cache = vm_cache_create(store);
if (cache == NULL)
panic("vm_map_physical_memory: vm_cache_create returned NULL");
cache_ref = vm_cache_ref_create(cache);
if (cache_ref == NULL)
panic("vm_map_physical_memory: vm_cache_ref_create returned NULL");
// acquire the cache ref once to represent the ref that the vnode will have
// this is one of the only places where we dont want to ref to ripple down to the store
vm_cache_acquire_ref(cache_ref, false);
// try to set the cache ptr in the vnode
if (vfs_set_cache_ptr(v, cache_ref) < 0) {
// the cache pointer was set between here and then
// this can only happen if someone else tries to map it
// at the same time. Rare enough to not worry about the
// performance impact of undoing what we just did and retrying
// this will delete the cache object and release the ref to the vnode we have
vm_cache_release_ref(cache_ref);
goto restart;
}
} else {
cache = cache_ref->cache;
store = cache->store;
}
status = vfs_get_vnode_cache(vnode, (void **)&cache_ref);
if (status < B_OK)
goto err2;
// acquire a ref to the cache before we do work on it. Dont ripple the ref acquision to the vnode
// below because we'll have to release it later anyway, since we grabbed a ref to the vnode at
// vfs_get_vnode_from_path(). This puts the ref counts in sync.
vm_cache_acquire_ref(cache_ref, false);
err = map_backing_store(aspace, store, address, offset, size, addr_type, 0, lock, mapping, &region, name);
status = map_backing_store(aspace, cache_ref->cache->store, _address, offset, size,
addressSpec, 0, lock, mapping, &area, name);
vm_cache_release_ref(cache_ref);
vm_put_aspace(aspace);
if (err < 0)
return err;
// modify the pointer returned to be offset back into the new region
// the same way the physical address in was offset
return region->id;
if (status < 0)
return status;
return area->id;
err2:
vfs_vnode_release_ref(vnode);
err1:
vm_put_aspace(aspace);
return status;
}