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Commit 6d8453df authored by Trond Myklebust's avatar Trond Myklebust Committed by Greg Kroah-Hartman
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SUNRPC: Reinitialise the backchannel request buffers before reuse 



commit 6622e3a73112fc336c1c2c582428fb5ef18e456a upstream.

When we're reusing the backchannel requests instead of freeing them,
then we should reinitialise any values of the send/receive xdr_bufs so
that they reflect the available space.

Fixes: 0d2a970d ("SUNRPC: Fix a backchannel race")
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d908b260

net/sunrpc/backchannel_rqst.c

+14 −0
Original line number Diff line number Diff line
@@ -69,6 +69,17 @@ static void xprt_free_allocation(struct rpc_rqst *req) 
	kfree(req);

}



static void xprt_bc_reinit_xdr_buf(struct xdr_buf *buf)

{

	buf->head[0].iov_len = PAGE_SIZE;

	buf->tail[0].iov_len = 0;

	buf->pages = NULL;

	buf->page_len = 0;

	buf->flags = 0;

	buf->len = 0;

	buf->buflen = PAGE_SIZE;

}



static int xprt_alloc_xdr_buf(struct xdr_buf *buf, gfp_t gfp_flags)

{

	struct page *page;
@@ -291,6 +302,9 @@ void xprt_free_bc_rqst(struct rpc_rqst *req) 
	 */

	spin_lock_bh(&xprt->bc_pa_lock);

	if (xprt_need_to_requeue(xprt)) {

		xprt_bc_reinit_xdr_buf(&req->rq_snd_buf);

		xprt_bc_reinit_xdr_buf(&req->rq_rcv_buf);

		req->rq_rcv_buf.len = PAGE_SIZE;

		list_add_tail(&req->rq_bc_pa_list, &xprt->bc_pa_list);

		xprt->bc_alloc_count++;

		req = NULL;