On Mon, Mar 01, 2021, Kai Huang wrote:
> + /*
> + * SECS pages are "pinned" by child pages, an unpinned once all
s/an/and
> + * children have been EREMOVE'd. A child page in this instance
> + * may have pinned an SECS page encountered in an earlier release(),
> + * creating a zombie. Since some children were EREMOVE'd above,
> + * try to EREMOVE all zombies in the hopes that one was unpinned.
> + */
> + mutex_lock(&zombie_secs_pages_lock);
> + list_for_each_entry_safe(epc_page, tmp, &zombie_secs_pages, list) {
> + /*
> + * Speculatively remove the page from the list of zombies,
> + * if the page is successfully EREMOVE it will be added to
> + * the list of free pages. If EREMOVE fails, throw the page
> + * on the local list, which will be spliced on at the end.
> + */
> + list_del(&epc_page->list);
> +
> + if (sgx_vepc_free_page(epc_page))
> + list_add_tail(&epc_page->list, &secs_pages);
> + }
> +
> + if (!list_empty(&secs_pages))
> + list_splice_tail(&secs_pages, &zombie_secs_pages);
> + mutex_unlock(&zombie_secs_pages_lock);
> +
> + kfree(vepc);
> +
> + return 0;
> +}
