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Rev 2948 Rev 3009
Line 72... Line 72...
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static futex_t unused_futex = FUTEX_INITIALIZER;
 72 
static futex_t unused_futex = FUTEX_INITIALIZER;
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/** List of unused structures. */
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/** List of unused structures. */
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static LIST_INITIALIZE(unused_head);
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static LIST_INITIALIZE(unused_head);
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/** Futex protecting the up_hash and ui_hash.
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/** Futex protecting the up_hash and ui_hash. */
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 *
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 * The locking strategy assumes that there will be at most one fibril for each
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 * dev_handle.  Therefore it will be sufficient to hold the futex for shorter
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 * times (i.e. only during hash table operations as opposed to holding it the
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 * whole time between an unsuccessful find and the following insert). Should the
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 * assumption break, the locking strategy for this futex will have to be
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 * reconsidered.
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 */
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static futex_t used_futex = FUTEX_INITIALIZER;
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static futex_t used_futex = FUTEX_INITIALIZER;
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/**
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/**
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 * Global hash table of all used fat_idx_t structures.
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 * Global hash table of all used fat_idx_t structures.
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 * The index structures are hashed by the dev_handle, parent node's first
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 * The index structures are hashed by the dev_handle, parent node's first
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        [UPH_PDI_KEY] = pdi,
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        [UPH_PDI_KEY] = pdi,
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    };
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    };
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    futex_down(&used_futex);
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    futex_down(&used_futex);
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    l = hash_table_find(&up_hash, pkey);
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    l = hash_table_find(&up_hash, pkey);
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    futex_up(&used_futex);
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    if (l) {
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    if (l) {
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        fidx = hash_table_get_instance(l, fat_idx_t, uph_link);
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        fidx = hash_table_get_instance(l, fat_idx_t, uph_link);
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    } else {
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    } else {
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        fidx = (fat_idx_t *) malloc(sizeof(fat_idx_t));
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        fidx = (fat_idx_t *) malloc(sizeof(fat_idx_t));
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        if (!fidx) {
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        if (!fidx) {
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            futex_up(&used_futex);
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            return NULL;
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            return NULL;
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        }
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        }
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        if (!fat_idx_alloc(dev_handle, &fidx->index)) {
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        if (!fat_idx_alloc(dev_handle, &fidx->index)) {
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            free(fidx);
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            free(fidx);
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            futex_up(&used_futex);
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            return NULL;
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            return NULL;
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        }
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        }
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        unsigned long ikey[] = {
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        unsigned long ikey[] = {
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            [UIH_DH_KEY] = dev_handle,
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            [UIH_DH_KEY] = dev_handle,
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            [UIH_INDEX_KEY] = fidx->index,
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            [UIH_INDEX_KEY] = fidx->index,
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        };
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        };
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        link_initialize(&fidx->uph_link);
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        link_initialize(&fidx->uph_link);
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        link_initialize(&fidx->uih_link);
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        link_initialize(&fidx->uih_link);
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        futex_initialize(&fidx->lock, 1);
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        fidx->dev_handle = dev_handle;
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        fidx->dev_handle = dev_handle;
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        fidx->pfc = pfc;
 370 
        fidx->pfc = pfc;
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        fidx->pdi = pdi;
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        fidx->pdi = pdi;
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        fidx->nodep = NULL;
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        fidx->nodep = NULL;
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        futex_down(&used_futex);
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        hash_table_insert(&up_hash, pkey, &fidx->uph_link);
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        hash_table_insert(&up_hash, pkey, &fidx->uph_link);
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        hash_table_insert(&ui_hash, ikey, &fidx->uih_link);
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        hash_table_insert(&ui_hash, ikey, &fidx->uih_link);
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        futex_up(&used_futex);
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    }
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    }
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    futex_down(&fidx->lock);
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    futex_up(&used_futex);
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 379 
 
386 
    return fidx;
 380 
    return fidx;
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}
 381 
}
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 382 
 
389 
fat_idx_t *
 383 
fat_idx_t *
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        [UIH_INDEX_KEY] = index,
 390 
        [UIH_INDEX_KEY] = index,
397 
    };
 391 
    };
398 
 
 392 
 
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    futex_down(&used_futex);
 393 
    futex_down(&used_futex);
400 
    l = hash_table_find(&ui_hash, ikey);
 394 
    l = hash_table_find(&ui_hash, ikey);
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    futex_up(&used_futex);
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402 
    if (l) {
 395 
    if (l) {
403 
        fidx = hash_table_get_instance(l, fat_idx_t, uih_link);
 396 
        fidx = hash_table_get_instance(l, fat_idx_t, uih_link);
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 397 
        futex_down(&fidx->lock);
404 
    }
 398 
    }
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 399 
    futex_up(&used_futex);
405 
 
 400 
 
406 
    return fidx;
 401 
    return fidx;
407 
}
 402 
}
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 403