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SUNRPC: Allow dynamic allocation of back channel slots

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Now that the reads happen in a process context rather than a softirq,
it is safe to allocate back channel slots using a reclaiming
allocation.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This commit is contained in:
Trond Myklebust 2019-03-02 13:12:22 -05:00
parent 067c469671
commit 0d1bf3407c
1 changed files with 24 additions and 15 deletions
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39
net/sunrpc/backchannel_rqst.c
View File

@ -235,7 +235,8 @@ void xprt_destroy_bc(struct rpc_xprt *xprt, unsigned int max_reqs)
list_empty(&xprt->bc_pa_list) ? "true" : "false");
}
static struct rpc_rqst *xprt_alloc_bc_request(struct rpc_xprt *xprt, __be32 xid)
static struct rpc_rqst *xprt_get_bc_request(struct rpc_xprt *xprt, __be32 xid,
struct rpc_rqst *new)
{
struct rpc_rqst *req = NULL;
@ -243,10 +244,9 @@ static struct rpc_rqst *xprt_alloc_bc_request(struct rpc_xprt *xprt, __be32 xid)
if (atomic_read(&xprt->bc_free_slots) <= 0)
goto not_found;
if (list_empty(&xprt->bc_pa_list)) {
req = xprt_alloc_bc_req(xprt, GFP_ATOMIC);
if (!req)
if (!new)
goto not_found;
list_add_tail(&req->rq_bc_pa_list, &xprt->bc_pa_list);
list_add_tail(&new->rq_bc_pa_list, &xprt->bc_pa_list);
xprt->bc_alloc_count++;
}
req = list_first_entry(&xprt->bc_pa_list, struct rpc_rqst,
@ -256,8 +256,8 @@ static struct rpc_rqst *xprt_alloc_bc_request(struct rpc_xprt *xprt, __be32 xid)
sizeof(req->rq_private_buf));
req->rq_xid = xid;
req->rq_connect_cookie = xprt->connect_cookie;
not_found:
dprintk("RPC: backchannel req=%p\n", req);
not_found:
return req;
}
@ -320,18 +320,27 @@ void xprt_free_bc_rqst(struct rpc_rqst *req)
*/
struct rpc_rqst *xprt_lookup_bc_request(struct rpc_xprt *xprt, __be32 xid)
{
struct rpc_rqst *req;
struct rpc_rqst *req, *new = NULL;
spin_lock(&xprt->bc_pa_lock);
list_for_each_entry(req, &xprt->bc_pa_list, rq_bc_pa_list) {
if (req->rq_connect_cookie != xprt->connect_cookie)
continue;
if (req->rq_xid == xid)
goto found;
}
req = xprt_alloc_bc_request(xprt, xid);
do {
spin_lock(&xprt->bc_pa_lock);
list_for_each_entry(req, &xprt->bc_pa_list, rq_bc_pa_list) {
if (req->rq_connect_cookie != xprt->connect_cookie)
continue;
if (req->rq_xid == xid)
goto found;
}
req = xprt_get_bc_request(xprt, xid, new);
found:
spin_unlock(&xprt->bc_pa_lock);
spin_unlock(&xprt->bc_pa_lock);
if (new) {
if (req != new)
xprt_free_bc_rqst(new);
break;
} else if (req)
break;
new = xprt_alloc_bc_req(xprt, GFP_KERNEL);
} while (new);
return req;
}