- const struct cl_page_slice *slice;
- ENTRY;
-
- page = cl_page_top_trusted((struct cl_page *)page);
- do {
- cfs_list_for_each_entry(slice, &page->cp_layers, cpl_linkage) {
- if (slice->cpl_obj->co_lu.lo_dev->ld_type == dtype)
- RETURN(slice);
- }
- page = page->cp_child;
- } while (page != NULL);
- RETURN(NULL);
-}
-
-/**
- * Returns a page with given index in the given object, or NULL if no page is
- * found. Acquires a reference on \a page.
- *
- * Locking: called under cl_object_header::coh_page_guard spin-lock.
- */
-struct cl_page *cl_page_lookup(struct cl_object_header *hdr, pgoff_t index)
-{
- struct cl_page *page;
-
- LASSERT(spin_is_locked(&hdr->coh_page_guard));
-
- page = radix_tree_lookup(&hdr->coh_tree, index);
- if (page != NULL)
- cl_page_get_trust(page);
- return page;
-}
-EXPORT_SYMBOL(cl_page_lookup);
-
-/**
- * Returns a list of pages by a given [start, end] of \a obj.
- *
- * \param resched If not NULL, then we give up before hogging CPU for too
- * long and set *resched = 1, in that case caller should implement a retry
- * logic.
- *
- * Gang tree lookup (radix_tree_gang_lookup()) optimization is absolutely
- * crucial in the face of [offset, EOF] locks.
- *
- * Return at least one page in @queue unless there is no covered page.
- */
-int cl_page_gang_lookup(const struct lu_env *env, struct cl_object *obj,
- struct cl_io *io, pgoff_t start, pgoff_t end,
- cl_page_gang_cb_t cb, void *cbdata)
-{
- struct cl_object_header *hdr;
- struct cl_page *page;
- struct cl_page **pvec;
- const struct cl_page_slice *slice;
- const struct lu_device_type *dtype;
- pgoff_t idx;
- unsigned int nr;
- unsigned int i;
- unsigned int j;
- int res = CLP_GANG_OKAY;
- int tree_lock = 1;
- ENTRY;
-
- idx = start;
- hdr = cl_object_header(obj);
- pvec = cl_env_info(env)->clt_pvec;
- dtype = cl_object_top(obj)->co_lu.lo_dev->ld_type;
- spin_lock(&hdr->coh_page_guard);
- while ((nr = radix_tree_gang_lookup(&hdr->coh_tree, (void **)pvec,
- idx, CLT_PVEC_SIZE)) > 0) {
- int end_of_region = 0;
- idx = pvec[nr - 1]->cp_index + 1;
- for (i = 0, j = 0; i < nr; ++i) {
- page = pvec[i];
- pvec[i] = NULL;
-
- LASSERT(page->cp_type == CPT_CACHEABLE);
- if (page->cp_index > end) {
- end_of_region = 1;
- break;
- }
- if (page->cp_state == CPS_FREEING)
- continue;
-
- slice = cl_page_at_trusted(page, dtype);
- /*
- * Pages for lsm-less file has no underneath sub-page
- * for osc, in case of ...
- */
- PASSERT(env, page, slice != NULL);
-
- page = slice->cpl_page;
- /*
- * Can safely call cl_page_get_trust() under
- * radix-tree spin-lock.
- *
- * XXX not true, because @page is from object another
- * than @hdr and protected by different tree lock.
- */
- cl_page_get_trust(page);
- lu_ref_add_atomic(&page->cp_reference,
- "gang_lookup", current);
- pvec[j++] = page;
- }
-
- /*
- * Here a delicate locking dance is performed. Current thread
- * holds a reference to a page, but has to own it before it
- * can be placed into queue. Owning implies waiting, so
- * radix-tree lock is to be released. After a wait one has to
- * check that pages weren't truncated (cl_page_own() returns
- * error in the latter case).
- */
- spin_unlock(&hdr->coh_page_guard);
- tree_lock = 0;
-
- for (i = 0; i < j; ++i) {
- page = pvec[i];
- if (res == CLP_GANG_OKAY)
- res = (*cb)(env, io, page, cbdata);
- lu_ref_del(&page->cp_reference,
- "gang_lookup", current);
- cl_page_put(env, page);
- }
- if (nr < CLT_PVEC_SIZE || end_of_region)
- break;
-
- if (res == CLP_GANG_OKAY && need_resched())
- res = CLP_GANG_RESCHED;
- if (res != CLP_GANG_OKAY)
- break;