Commit 22cc2ba5 authored by Chuck Lever's avatar Chuck Lever
Browse files

SUNRPC: Handle NULL entries in svc_rqst_release_pages 



svc_rqst_release_pages() releases response pages between rq_respages
and rq_next_page. It currently passes the entire range to
release_pages(), which does not expect NULL entries.

A subsequent patch preserves the rq_next_page pointer in
svc_rdma_save_io_pages() so that it accurately records how many
response pages were consumed. After that change, the range

  [rq_respages, rq_next_page)

can contain NULL entries where pages have already been transferred
to a send context.

Iterate through the range entry by entry, skipping NULLs, to handle
this case correctly.

Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent ee66b9e3

net/sunrpc/svc.c

+14 −8
Original line number Diff line number Diff line
@@ -990,19 +990,25 @@ EXPORT_SYMBOL_GPL(svc_rqst_replace_page); 
 * svc_rqst_release_pages - Release Reply buffer pages

 * @rqstp: RPC transaction context

 *

 * Release response pages that might still be in flight after

 * svc_send, and any spliced filesystem-owned pages.

 * Release response pages in the range [rq_respages, rq_next_page).

 * NULL entries in this range are skipped, allowing transports to

 * transfer pages to a send context before this function runs.

 */

void svc_rqst_release_pages(struct svc_rqst *rqstp)

{

	int i, count = rqstp->rq_next_page - rqstp->rq_respages;

	struct page **pp;



	if (count) {

		release_pages(rqstp->rq_respages, count);

		for (i = 0; i < count; i++)

			rqstp->rq_respages[i] = NULL;

	for (pp = rqstp->rq_respages; pp < rqstp->rq_next_page; pp++) {

		if (*pp) {

			if (!folio_batch_add(&rqstp->rq_fbatch,

					     page_folio(*pp)))

				__folio_batch_release(&rqstp->rq_fbatch);

			*pp = NULL;

		}

	}

	if (rqstp->rq_fbatch.nr)

		__folio_batch_release(&rqstp->rq_fbatch);

}



/**

 * svc_exit_thread - finalise the termination of a sunrpc server thread