blob: 1baa41099469dad441d7c3edff1480138645ff4a [file] [log] [blame]
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -04001/******************************************************************************
2
3(c) 2007 Network Appliance, Inc. All Rights Reserved.
4(c) 2009 NetApp. All Rights Reserved.
5
6NetApp provides this source code under the GPL v2 License.
7The GPL v2 license is available at
8http://opensource.org/licenses/gpl-license.php.
9
10THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
11"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
12LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
13A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
14CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
15EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
16PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
17PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
18LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
19NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
20SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
21
22******************************************************************************/
23
24#include <linux/tcp.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090025#include <linux/slab.h>
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -040026#include <linux/sunrpc/xprt.h>
Paul Gortmakerbc3b2d72011-07-15 11:47:34 -040027#include <linux/export.h>
Trond Myklebust09acfea2012-03-11 15:22:54 -040028#include <linux/sunrpc/bc_xprt.h>
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -040029
Jeff Laytonf895b252014-11-17 16:58:04 -050030#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -040031#define RPCDBG_FACILITY RPCDBG_TRANS
32#endif
33
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -040034/*
35 * Helper routines that track the number of preallocation elements
36 * on the transport.
37 */
38static inline int xprt_need_to_requeue(struct rpc_xprt *xprt)
39{
40 return xprt->bc_alloc_count > 0;
41}
42
43static inline void xprt_inc_alloc_count(struct rpc_xprt *xprt, unsigned int n)
44{
45 xprt->bc_alloc_count += n;
46}
47
48static inline int xprt_dec_alloc_count(struct rpc_xprt *xprt, unsigned int n)
49{
50 return xprt->bc_alloc_count -= n;
51}
52
53/*
54 * Free the preallocated rpc_rqst structure and the memory
55 * buffers hanging off of it.
56 */
57static void xprt_free_allocation(struct rpc_rqst *req)
58{
59 struct xdr_buf *xbufp;
60
61 dprintk("RPC: free allocations for req= %p\n", req);
Weston Andros Adamsonf30dfbb2012-10-23 10:43:33 -040062 WARN_ON_ONCE(test_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state));
Trond Myklebust88de6af2015-06-01 15:10:25 -040063 xbufp = &req->rq_rcv_buf;
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -040064 free_page((unsigned long)xbufp->head[0].iov_base);
65 xbufp = &req->rq_snd_buf;
66 free_page((unsigned long)xbufp->head[0].iov_base);
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -040067 kfree(req);
68}
69
Trond Myklebust1dddda82015-06-01 15:05:38 -040070static int xprt_alloc_xdr_buf(struct xdr_buf *buf, gfp_t gfp_flags)
71{
72 struct page *page;
73 /* Preallocate one XDR receive buffer */
74 page = alloc_page(gfp_flags);
75 if (page == NULL)
76 return -ENOMEM;
77 buf->head[0].iov_base = page_address(page);
78 buf->head[0].iov_len = PAGE_SIZE;
79 buf->tail[0].iov_base = NULL;
80 buf->tail[0].iov_len = 0;
81 buf->page_len = 0;
82 buf->len = 0;
83 buf->buflen = PAGE_SIZE;
84 return 0;
85}
86
87static
88struct rpc_rqst *xprt_alloc_bc_req(struct rpc_xprt *xprt, gfp_t gfp_flags)
89{
90 struct rpc_rqst *req;
91
92 /* Pre-allocate one backchannel rpc_rqst */
93 req = kzalloc(sizeof(*req), gfp_flags);
94 if (req == NULL)
95 return NULL;
96
97 req->rq_xprt = xprt;
98 INIT_LIST_HEAD(&req->rq_list);
99 INIT_LIST_HEAD(&req->rq_bc_list);
100
101 /* Preallocate one XDR receive buffer */
102 if (xprt_alloc_xdr_buf(&req->rq_rcv_buf, gfp_flags) < 0) {
103 printk(KERN_ERR "Failed to create bc receive xbuf\n");
104 goto out_free;
105 }
106 req->rq_rcv_buf.len = PAGE_SIZE;
107
108 /* Preallocate one XDR send buffer */
109 if (xprt_alloc_xdr_buf(&req->rq_snd_buf, gfp_flags) < 0) {
110 printk(KERN_ERR "Failed to create bc snd xbuf\n");
111 goto out_free;
112 }
113 return req;
114out_free:
115 xprt_free_allocation(req);
116 return NULL;
117}
118
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400119/*
120 * Preallocate up to min_reqs structures and related buffers for use
121 * by the backchannel. This function can be called multiple times
122 * when creating new sessions that use the same rpc_xprt. The
123 * preallocated buffers are added to the pool of resources used by
124 * the rpc_xprt. Anyone of these resources may be used used by an
125 * incoming callback request. It's up to the higher levels in the
126 * stack to enforce that the maximum number of session slots is not
127 * being exceeded.
128 *
129 * Some callback arguments can be large. For example, a pNFS server
130 * using multiple deviceids. The list can be unbound, but the client
131 * has the ability to tell the server the maximum size of the callback
132 * requests. Each deviceID is 16 bytes, so allocate one page
133 * for the arguments to have enough room to receive a number of these
134 * deviceIDs. The NFS client indicates to the pNFS server that its
135 * callback requests can be up to 4096 bytes in size.
136 */
137int xprt_setup_backchannel(struct rpc_xprt *xprt, unsigned int min_reqs)
138{
Trond Myklebust1dddda82015-06-01 15:05:38 -0400139 struct rpc_rqst *req;
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400140 struct list_head tmp_list;
141 int i;
142
143 dprintk("RPC: setup backchannel transport\n");
144
145 /*
146 * We use a temporary list to keep track of the preallocated
147 * buffers. Once we're done building the list we splice it
148 * into the backchannel preallocation list off of the rpc_xprt
149 * struct. This helps minimize the amount of time the list
150 * lock is held on the rpc_xprt struct. It also makes cleanup
151 * easier in case of memory allocation errors.
152 */
153 INIT_LIST_HEAD(&tmp_list);
154 for (i = 0; i < min_reqs; i++) {
155 /* Pre-allocate one backchannel rpc_rqst */
Trond Myklebust1dddda82015-06-01 15:05:38 -0400156 req = xprt_alloc_bc_req(xprt, GFP_KERNEL);
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400157 if (req == NULL) {
158 printk(KERN_ERR "Failed to create bc rpc_rqst\n");
159 goto out_free;
160 }
161
162 /* Add the allocated buffer to the tmp list */
163 dprintk("RPC: adding req= %p\n", req);
164 list_add(&req->rq_bc_pa_list, &tmp_list);
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400165 }
166
167 /*
168 * Add the temporary list to the backchannel preallocation list
169 */
170 spin_lock_bh(&xprt->bc_pa_lock);
171 list_splice(&tmp_list, &xprt->bc_pa_list);
172 xprt_inc_alloc_count(xprt, min_reqs);
173 spin_unlock_bh(&xprt->bc_pa_lock);
174
175 dprintk("RPC: setup backchannel transport done\n");
176 return 0;
177
178out_free:
179 /*
180 * Memory allocation failed, free the temporary list
181 */
Trond Myklebust1dddda82015-06-01 15:05:38 -0400182 while (!list_empty(&tmp_list)) {
183 req = list_first_entry(&tmp_list,
184 struct rpc_rqst,
185 rq_bc_pa_list);
Trond Myklebust62835672014-02-11 13:56:54 -0500186 list_del(&req->rq_bc_pa_list);
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400187 xprt_free_allocation(req);
Trond Myklebust62835672014-02-11 13:56:54 -0500188 }
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400189
190 dprintk("RPC: setup backchannel transport failed\n");
Weston Andros Adamsond24bab92012-11-01 11:21:53 -0400191 return -ENOMEM;
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400192}
Trond Myklebust0d961aa2011-07-13 19:24:15 -0400193EXPORT_SYMBOL_GPL(xprt_setup_backchannel);
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400194
Ben Hutchings2c530402012-07-10 10:55:09 +0000195/**
196 * xprt_destroy_backchannel - Destroys the backchannel preallocated structures.
197 * @xprt: the transport holding the preallocated strucures
198 * @max_reqs the maximum number of preallocated structures to destroy
199 *
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400200 * Since these structures may have been allocated by multiple calls
201 * to xprt_setup_backchannel, we only destroy up to the maximum number
202 * of reqs specified by the caller.
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400203 */
204void xprt_destroy_backchannel(struct rpc_xprt *xprt, unsigned int max_reqs)
205{
206 struct rpc_rqst *req = NULL, *tmp = NULL;
207
208 dprintk("RPC: destroy backchannel transport\n");
209
Weston Andros Adamsonc4ded8d2012-10-23 10:43:34 -0400210 if (max_reqs == 0)
211 goto out;
212
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400213 spin_lock_bh(&xprt->bc_pa_lock);
214 xprt_dec_alloc_count(xprt, max_reqs);
215 list_for_each_entry_safe(req, tmp, &xprt->bc_pa_list, rq_bc_pa_list) {
216 dprintk("RPC: req=%p\n", req);
Trond Myklebust62835672014-02-11 13:56:54 -0500217 list_del(&req->rq_bc_pa_list);
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400218 xprt_free_allocation(req);
219 if (--max_reqs == 0)
220 break;
221 }
222 spin_unlock_bh(&xprt->bc_pa_lock);
223
Weston Andros Adamsonc4ded8d2012-10-23 10:43:34 -0400224out:
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400225 dprintk("RPC: backchannel list empty= %s\n",
226 list_empty(&xprt->bc_pa_list) ? "true" : "false");
227}
Trond Myklebust0d961aa2011-07-13 19:24:15 -0400228EXPORT_SYMBOL_GPL(xprt_destroy_backchannel);
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400229
Trond Myklebust2ea24492014-02-10 11:18:39 -0500230static struct rpc_rqst *xprt_alloc_bc_request(struct rpc_xprt *xprt, __be32 xid)
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400231{
Trond Myklebust2ea24492014-02-10 11:18:39 -0500232 struct rpc_rqst *req = NULL;
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400233
234 dprintk("RPC: allocate a backchannel request\n");
Trond Myklebust2ea24492014-02-10 11:18:39 -0500235 if (list_empty(&xprt->bc_pa_list))
236 goto not_found;
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400237
Trond Myklebust2ea24492014-02-10 11:18:39 -0500238 req = list_first_entry(&xprt->bc_pa_list, struct rpc_rqst,
239 rq_bc_pa_list);
240 req->rq_reply_bytes_recvd = 0;
241 req->rq_bytes_sent = 0;
242 memcpy(&req->rq_private_buf, &req->rq_rcv_buf,
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400243 sizeof(req->rq_private_buf));
Trond Myklebust2ea24492014-02-10 11:18:39 -0500244 req->rq_xid = xid;
245 req->rq_connect_cookie = xprt->connect_cookie;
246not_found:
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400247 dprintk("RPC: backchannel req=%p\n", req);
248 return req;
249}
250
251/*
252 * Return the preallocated rpc_rqst structure and XDR buffers
253 * associated with this rpc_task.
254 */
255void xprt_free_bc_request(struct rpc_rqst *req)
256{
257 struct rpc_xprt *xprt = req->rq_xprt;
258
259 dprintk("RPC: free backchannel req=%p\n", req);
260
Trond Myklebust2ea24492014-02-10 11:18:39 -0500261 req->rq_connect_cookie = xprt->connect_cookie - 1;
Peter Zijlstra4e857c52014-03-17 18:06:10 +0100262 smp_mb__before_atomic();
Weston Andros Adamsonf30dfbb2012-10-23 10:43:33 -0400263 WARN_ON_ONCE(!test_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state));
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400264 clear_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
Peter Zijlstra4e857c52014-03-17 18:06:10 +0100265 smp_mb__after_atomic();
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400266
267 if (!xprt_need_to_requeue(xprt)) {
268 /*
269 * The last remaining session was destroyed while this
270 * entry was in use. Free the entry and don't attempt
271 * to add back to the list because there is no need to
272 * have anymore preallocated entries.
273 */
274 dprintk("RPC: Last session removed req=%p\n", req);
275 xprt_free_allocation(req);
276 return;
277 }
278
279 /*
280 * Return it to the list of preallocations so that it
281 * may be reused by a new callback request.
282 */
283 spin_lock_bh(&xprt->bc_pa_lock);
Trond Myklebust2ea24492014-02-10 11:18:39 -0500284 list_add_tail(&req->rq_bc_pa_list, &xprt->bc_pa_list);
Ricardo Labiagafb7a0b92009-04-01 09:23:00 -0400285 spin_unlock_bh(&xprt->bc_pa_lock);
286}
287
Trond Myklebust2ea24492014-02-10 11:18:39 -0500288/*
289 * One or more rpc_rqst structure have been preallocated during the
290 * backchannel setup. Buffer space for the send and private XDR buffers
291 * has been preallocated as well. Use xprt_alloc_bc_request to allocate
292 * to this request. Use xprt_free_bc_request to return it.
293 *
294 * We know that we're called in soft interrupt context, grab the spin_lock
295 * since there is no need to grab the bottom half spin_lock.
296 *
297 * Return an available rpc_rqst, otherwise NULL if non are available.
298 */
299struct rpc_rqst *xprt_lookup_bc_request(struct rpc_xprt *xprt, __be32 xid)
300{
301 struct rpc_rqst *req;
302
303 spin_lock(&xprt->bc_pa_lock);
304 list_for_each_entry(req, &xprt->bc_pa_list, rq_bc_pa_list) {
305 if (req->rq_connect_cookie != xprt->connect_cookie)
306 continue;
307 if (req->rq_xid == xid)
308 goto found;
309 }
310 req = xprt_alloc_bc_request(xprt, xid);
311found:
312 spin_unlock(&xprt->bc_pa_lock);
313 return req;
314}
315
316/*
317 * Add callback request to callback list. The callback
318 * service sleeps on the sv_cb_waitq waiting for new
319 * requests. Wake it up after adding enqueing the
320 * request.
321 */
322void xprt_complete_bc_request(struct rpc_rqst *req, uint32_t copied)
323{
324 struct rpc_xprt *xprt = req->rq_xprt;
325 struct svc_serv *bc_serv = xprt->bc_serv;
326
Chuck Lever813b00d2015-02-13 13:08:25 -0500327 spin_lock(&xprt->bc_pa_lock);
328 list_del(&req->rq_bc_pa_list);
329 spin_unlock(&xprt->bc_pa_lock);
330
Trond Myklebust2ea24492014-02-10 11:18:39 -0500331 req->rq_private_buf.len = copied;
332 set_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
333
334 dprintk("RPC: add callback request to list\n");
335 spin_lock(&bc_serv->sv_cb_lock);
Trond Myklebust2ea24492014-02-10 11:18:39 -0500336 list_add(&req->rq_bc_list, &bc_serv->sv_cb_list);
337 wake_up(&bc_serv->sv_cb_waitq);
338 spin_unlock(&bc_serv->sv_cb_lock);
339}
340