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nfs41: sunrpc: xprt_alloc_bc_request() should not use spin_lock_bh() 

xprt_alloc_bc_request() is always called in soft interrupt context.
Grab the spin_lock instead of the bottom half spin_lock.  Softirqs
do not preempt other softirqs running on the same processor, so there
is no need to disable bottom halves.

Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Ricardo Labiaga 2009-06-18 22:01:24 -04:00 committed by Trond Myklebust
parent 578e458568
commit e9f0298558
1 changed files with 5 additions and 2 deletions
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7
net/sunrpc/backchannel_rqst.c
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@ -211,6 +211,9 @@ EXPORT_SYMBOL(xprt_destroy_backchannel);
* has been preallocated as well. Use xprt_alloc_bc_request to allocate * has been preallocated as well. Use xprt_alloc_bc_request to allocate
* to this request. Use xprt_free_bc_request to return it. * to this request. Use xprt_free_bc_request to return it.
* *
* We know that we're called in soft interrupt context, grab the spin_lock
* since there is no need to grab the bottom half spin_lock.
*
* Return an available rpc_rqst, otherwise NULL if non are available. * Return an available rpc_rqst, otherwise NULL if non are available.
*/ */
struct rpc_rqst *xprt_alloc_bc_request(struct rpc_xprt *xprt) struct rpc_rqst *xprt_alloc_bc_request(struct rpc_xprt *xprt)
@ -218,7 +221,7 @@ struct rpc_rqst *xprt_alloc_bc_request(struct rpc_xprt *xprt)
struct rpc_rqst *req; struct rpc_rqst *req;
dprintk("RPC: allocate a backchannel request\n"); dprintk("RPC: allocate a backchannel request\n");
spin_lock_bh(&xprt->bc_pa_lock); spin_lock(&xprt->bc_pa_lock);
if (!list_empty(&xprt->bc_pa_list)) { if (!list_empty(&xprt->bc_pa_list)) {
req = list_first_entry(&xprt->bc_pa_list, struct rpc_rqst, req = list_first_entry(&xprt->bc_pa_list, struct rpc_rqst,
rq_bc_pa_list); rq_bc_pa_list);
@ -226,7 +229,7 @@ struct rpc_rqst *xprt_alloc_bc_request(struct rpc_xprt *xprt)
} else { } else {
req = NULL; req = NULL;
} }
spin_unlock_bh(&xprt->bc_pa_lock); spin_unlock(&xprt->bc_pa_lock);
if (req != NULL) { if (req != NULL) {
set_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state); set_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);