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SUNRPC: Reinitialise the backchannel request buffers before reuse 

commit 6622e3a731 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: 0d2a970d0a ("SUNRPC: Fix a backchannel race")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Trond Myklebust 2022-07-27 12:27:54 -04:00 committed by Greg Kroah-Hartman
parent 0fffb46ff3
commit 1429b2fa35
1 changed files with 14 additions and 0 deletions
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14
net/sunrpc/backchannel_rqst.c
View File

@ -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;