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authorNeilBrown <neilb@suse.de>2023-05-09 09:42:47 +1000
committerChuck Lever <chuck.lever@oracle.com>2023-05-14 15:55:02 -0400
commit948f072ada23e0a504c5e4d7d71d4c83bd0785ec (patch)
tree35e02b9a854af2107953dc9e7150bc98be37e453 /net/sunrpc/svc_xprt.c
parenteb8d3a2c809abd73ab0a060fe971d6b9019aa3c1 (diff)
SUNRPC: always free ctxt when freeing deferred request
Since the ->xprt_ctxt pointer was added to svc_deferred_req, it has not been sufficient to use kfree() to free a deferred request. We may need to free the ctxt as well. As freeing the ctxt is all that ->xpo_release_rqst() does, we repurpose it to explicit do that even when the ctxt is not stored in an rqst. So we now have ->xpo_release_ctxt() which is given an xprt and a ctxt, which may have been taken either from an rqst or from a dreq. The caller is now responsible for clearing that pointer after the call to ->xpo_release_ctxt. We also clear dr->xprt_ctxt when the ctxt is moved into a new rqst when revisiting a deferred request. This ensures there is only one pointer to the ctxt, so the risk of double freeing in future is reduced. The new code in svc_xprt_release which releases both the ctxt and any rq_deferred depends on this. Fixes: 773f91b2cf3f ("SUNRPC: Fix NFSD's request deferral on RDMA transports") Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to 'net/sunrpc/svc_xprt.c')
-rw-r--r--net/sunrpc/svc_xprt.c23
1 files changed, 17 insertions, 6 deletions
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 5fd94f6bdc75..13a14897bc17 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -532,13 +532,23 @@ void svc_reserve(struct svc_rqst *rqstp, int space)
}
EXPORT_SYMBOL_GPL(svc_reserve);
+static void free_deferred(struct svc_xprt *xprt, struct svc_deferred_req *dr)
+{
+ if (!dr)
+ return;
+
+ xprt->xpt_ops->xpo_release_ctxt(xprt, dr->xprt_ctxt);
+ kfree(dr);
+}
+
static void svc_xprt_release(struct svc_rqst *rqstp)
{
struct svc_xprt *xprt = rqstp->rq_xprt;
- xprt->xpt_ops->xpo_release_rqst(rqstp);
+ xprt->xpt_ops->xpo_release_ctxt(xprt, rqstp->rq_xprt_ctxt);
+ rqstp->rq_xprt_ctxt = NULL;
- kfree(rqstp->rq_deferred);
+ free_deferred(xprt, rqstp->rq_deferred);
rqstp->rq_deferred = NULL;
svc_rqst_release_pages(rqstp);
@@ -1054,7 +1064,7 @@ static void svc_delete_xprt(struct svc_xprt *xprt)
spin_unlock_bh(&serv->sv_lock);
while ((dr = svc_deferred_dequeue(xprt)) != NULL)
- kfree(dr);
+ free_deferred(xprt, dr);
call_xpt_users(xprt);
svc_xprt_put(xprt);
@@ -1176,8 +1186,8 @@ static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
spin_unlock(&xprt->xpt_lock);
trace_svc_defer_drop(dr);
+ free_deferred(xprt, dr);
svc_xprt_put(xprt);
- kfree(dr);
return;
}
dr->xprt = NULL;
@@ -1222,14 +1232,13 @@ static struct cache_deferred_req *svc_defer(struct cache_req *req)
dr->addrlen = rqstp->rq_addrlen;
dr->daddr = rqstp->rq_daddr;
dr->argslen = rqstp->rq_arg.len >> 2;
- dr->xprt_ctxt = rqstp->rq_xprt_ctxt;
/* back up head to the start of the buffer and copy */
skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
dr->argslen << 2);
}
- WARN_ON_ONCE(rqstp->rq_xprt_ctxt != dr->xprt_ctxt);
+ dr->xprt_ctxt = rqstp->rq_xprt_ctxt;
rqstp->rq_xprt_ctxt = NULL;
trace_svc_defer(rqstp);
svc_xprt_get(rqstp->rq_xprt);
@@ -1263,6 +1272,8 @@ static noinline int svc_deferred_recv(struct svc_rqst *rqstp)
rqstp->rq_daddr = dr->daddr;
rqstp->rq_respages = rqstp->rq_pages;
rqstp->rq_xprt_ctxt = dr->xprt_ctxt;
+
+ dr->xprt_ctxt = NULL;
svc_xprt_received(rqstp->rq_xprt);
return dr->argslen << 2;
}