Merge tag 'arc-5.12-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc
[linux-block.git] / net / sunrpc / backchannel_rqst.c
CommitLineData
fb7a0b9a
RL
1/******************************************************************************
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
0bdd4cea 8https://opensource.org/licenses/gpl-license.php.
fb7a0b9a
RL
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>
5a0e3ad6 25#include <linux/slab.h>
fb7a0b9a 26#include <linux/sunrpc/xprt.h>
bc3b2d7f 27#include <linux/export.h>
09acfea5 28#include <linux/sunrpc/bc_xprt.h>
fb7a0b9a 29
f895b252 30#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
fb7a0b9a
RL
31#define RPCDBG_FACILITY RPCDBG_TRANS
32#endif
33
7402a4fe
TM
34#define BC_MAX_SLOTS 64U
35
36unsigned int xprt_bc_max_slots(struct rpc_xprt *xprt)
37{
38 return BC_MAX_SLOTS;
39}
40
fb7a0b9a
RL
41/*
42 * Helper routines that track the number of preallocation elements
43 * on the transport.
44 */
45static inline int xprt_need_to_requeue(struct rpc_xprt *xprt)
46{
7402a4fe 47 return xprt->bc_alloc_count < xprt->bc_alloc_max;
fb7a0b9a
RL
48}
49
50/*
51 * Free the preallocated rpc_rqst structure and the memory
52 * buffers hanging off of it.
53 */
54static void xprt_free_allocation(struct rpc_rqst *req)
55{
56 struct xdr_buf *xbufp;
57
58 dprintk("RPC: free allocations for req= %p\n", req);
f30dfbba 59 WARN_ON_ONCE(test_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state));
88de6af2 60 xbufp = &req->rq_rcv_buf;
fb7a0b9a
RL
61 free_page((unsigned long)xbufp->head[0].iov_base);
62 xbufp = &req->rq_snd_buf;
63 free_page((unsigned long)xbufp->head[0].iov_base);
fb7a0b9a
RL
64 kfree(req);
65}
66
1dddda86
TM
67static int xprt_alloc_xdr_buf(struct xdr_buf *buf, gfp_t gfp_flags)
68{
69 struct page *page;
70 /* Preallocate one XDR receive buffer */
71 page = alloc_page(gfp_flags);
72 if (page == NULL)
73 return -ENOMEM;
b9c5bc03 74 xdr_buf_init(buf, page_address(page), PAGE_SIZE);
1dddda86
TM
75 return 0;
76}
77
78static
79struct rpc_rqst *xprt_alloc_bc_req(struct rpc_xprt *xprt, gfp_t gfp_flags)
80{
81 struct rpc_rqst *req;
82
83 /* Pre-allocate one backchannel rpc_rqst */
84 req = kzalloc(sizeof(*req), gfp_flags);
85 if (req == NULL)
86 return NULL;
87
88 req->rq_xprt = xprt;
1dddda86
TM
89 INIT_LIST_HEAD(&req->rq_bc_list);
90
91 /* Preallocate one XDR receive buffer */
92 if (xprt_alloc_xdr_buf(&req->rq_rcv_buf, gfp_flags) < 0) {
93 printk(KERN_ERR "Failed to create bc receive xbuf\n");
94 goto out_free;
95 }
96 req->rq_rcv_buf.len = PAGE_SIZE;
97
98 /* Preallocate one XDR send buffer */
99 if (xprt_alloc_xdr_buf(&req->rq_snd_buf, gfp_flags) < 0) {
100 printk(KERN_ERR "Failed to create bc snd xbuf\n");
101 goto out_free;
102 }
103 return req;
104out_free:
105 xprt_free_allocation(req);
106 return NULL;
107}
108
fb7a0b9a
RL
109/*
110 * Preallocate up to min_reqs structures and related buffers for use
111 * by the backchannel. This function can be called multiple times
112 * when creating new sessions that use the same rpc_xprt. The
113 * preallocated buffers are added to the pool of resources used by
1cc5213b 114 * the rpc_xprt. Any one of these resources may be used by an
fb7a0b9a
RL
115 * incoming callback request. It's up to the higher levels in the
116 * stack to enforce that the maximum number of session slots is not
117 * being exceeded.
118 *
119 * Some callback arguments can be large. For example, a pNFS server
120 * using multiple deviceids. The list can be unbound, but the client
121 * has the ability to tell the server the maximum size of the callback
122 * requests. Each deviceID is 16 bytes, so allocate one page
123 * for the arguments to have enough room to receive a number of these
124 * deviceIDs. The NFS client indicates to the pNFS server that its
125 * callback requests can be up to 4096 bytes in size.
126 */
127int xprt_setup_backchannel(struct rpc_xprt *xprt, unsigned int min_reqs)
42e5c3e2
CL
128{
129 if (!xprt->ops->bc_setup)
130 return 0;
131 return xprt->ops->bc_setup(xprt, min_reqs);
132}
133EXPORT_SYMBOL_GPL(xprt_setup_backchannel);
134
135int xprt_setup_bc(struct rpc_xprt *xprt, unsigned int min_reqs)
fb7a0b9a 136{
1dddda86 137 struct rpc_rqst *req;
fb7a0b9a
RL
138 struct list_head tmp_list;
139 int i;
140
141 dprintk("RPC: setup backchannel transport\n");
142
7402a4fe
TM
143 if (min_reqs > BC_MAX_SLOTS)
144 min_reqs = BC_MAX_SLOTS;
145
fb7a0b9a
RL
146 /*
147 * We use a temporary list to keep track of the preallocated
148 * buffers. Once we're done building the list we splice it
149 * into the backchannel preallocation list off of the rpc_xprt
150 * struct. This helps minimize the amount of time the list
151 * lock is held on the rpc_xprt struct. It also makes cleanup
152 * easier in case of memory allocation errors.
153 */
154 INIT_LIST_HEAD(&tmp_list);
155 for (i = 0; i < min_reqs; i++) {
156 /* Pre-allocate one backchannel rpc_rqst */
1dddda86 157 req = xprt_alloc_bc_req(xprt, GFP_KERNEL);
fb7a0b9a
RL
158 if (req == NULL) {
159 printk(KERN_ERR "Failed to create bc rpc_rqst\n");
160 goto out_free;
161 }
162
163 /* Add the allocated buffer to the tmp list */
164 dprintk("RPC: adding req= %p\n", req);
165 list_add(&req->rq_bc_pa_list, &tmp_list);
fb7a0b9a
RL
166 }
167
168 /*
169 * Add the temporary list to the backchannel preallocation list
170 */
c89091c8 171 spin_lock(&xprt->bc_pa_lock);
fb7a0b9a 172 list_splice(&tmp_list, &xprt->bc_pa_list);
7402a4fe
TM
173 xprt->bc_alloc_count += min_reqs;
174 xprt->bc_alloc_max += min_reqs;
175 atomic_add(min_reqs, &xprt->bc_slot_count);
c89091c8 176 spin_unlock(&xprt->bc_pa_lock);
fb7a0b9a
RL
177
178 dprintk("RPC: setup backchannel transport done\n");
179 return 0;
180
181out_free:
182 /*
183 * Memory allocation failed, free the temporary list
184 */
1dddda86
TM
185 while (!list_empty(&tmp_list)) {
186 req = list_first_entry(&tmp_list,
187 struct rpc_rqst,
188 rq_bc_pa_list);
62835679 189 list_del(&req->rq_bc_pa_list);
fb7a0b9a 190 xprt_free_allocation(req);
62835679 191 }
fb7a0b9a
RL
192
193 dprintk("RPC: setup backchannel transport failed\n");
d24bab93 194 return -ENOMEM;
fb7a0b9a 195}
fb7a0b9a 196
2c53040f
BH
197/**
198 * xprt_destroy_backchannel - Destroys the backchannel preallocated structures.
199 * @xprt: the transport holding the preallocated strucures
acf0a39f 200 * @max_reqs: the maximum number of preallocated structures to destroy
2c53040f 201 *
fb7a0b9a
RL
202 * Since these structures may have been allocated by multiple calls
203 * to xprt_setup_backchannel, we only destroy up to the maximum number
204 * of reqs specified by the caller.
fb7a0b9a
RL
205 */
206void xprt_destroy_backchannel(struct rpc_xprt *xprt, unsigned int max_reqs)
42e5c3e2
CL
207{
208 if (xprt->ops->bc_destroy)
209 xprt->ops->bc_destroy(xprt, max_reqs);
210}
211EXPORT_SYMBOL_GPL(xprt_destroy_backchannel);
212
213void xprt_destroy_bc(struct rpc_xprt *xprt, unsigned int max_reqs)
fb7a0b9a
RL
214{
215 struct rpc_rqst *req = NULL, *tmp = NULL;
216
217 dprintk("RPC: destroy backchannel transport\n");
218
c4ded8d9
WAA
219 if (max_reqs == 0)
220 goto out;
221
fb7a0b9a 222 spin_lock_bh(&xprt->bc_pa_lock);
669996ad 223 xprt->bc_alloc_max -= min(max_reqs, xprt->bc_alloc_max);
fb7a0b9a
RL
224 list_for_each_entry_safe(req, tmp, &xprt->bc_pa_list, rq_bc_pa_list) {
225 dprintk("RPC: req=%p\n", req);
62835679 226 list_del(&req->rq_bc_pa_list);
fb7a0b9a 227 xprt_free_allocation(req);
7402a4fe
TM
228 xprt->bc_alloc_count--;
229 atomic_dec(&xprt->bc_slot_count);
fb7a0b9a
RL
230 if (--max_reqs == 0)
231 break;
232 }
233 spin_unlock_bh(&xprt->bc_pa_lock);
234
c4ded8d9 235out:
fb7a0b9a
RL
236 dprintk("RPC: backchannel list empty= %s\n",
237 list_empty(&xprt->bc_pa_list) ? "true" : "false");
238}
fb7a0b9a 239
0d1bf340
TM
240static struct rpc_rqst *xprt_get_bc_request(struct rpc_xprt *xprt, __be32 xid,
241 struct rpc_rqst *new)
fb7a0b9a 242{
2ea24497 243 struct rpc_rqst *req = NULL;
fb7a0b9a
RL
244
245 dprintk("RPC: allocate a backchannel request\n");
0d2a970d 246 if (list_empty(&xprt->bc_pa_list)) {
0d1bf340 247 if (!new)
0d2a970d 248 goto not_found;
7402a4fe
TM
249 if (atomic_read(&xprt->bc_slot_count) >= BC_MAX_SLOTS)
250 goto not_found;
0d1bf340 251 list_add_tail(&new->rq_bc_pa_list, &xprt->bc_pa_list);
68514471 252 xprt->bc_alloc_count++;
7402a4fe 253 atomic_inc(&xprt->bc_slot_count);
0d2a970d 254 }
2ea24497
TM
255 req = list_first_entry(&xprt->bc_pa_list, struct rpc_rqst,
256 rq_bc_pa_list);
257 req->rq_reply_bytes_recvd = 0;
2ea24497 258 memcpy(&req->rq_private_buf, &req->rq_rcv_buf,
fb7a0b9a 259 sizeof(req->rq_private_buf));
2ea24497
TM
260 req->rq_xid = xid;
261 req->rq_connect_cookie = xprt->connect_cookie;
fb7a0b9a 262 dprintk("RPC: backchannel req=%p\n", req);
0d1bf340 263not_found:
fb7a0b9a
RL
264 return req;
265}
266
267/*
268 * Return the preallocated rpc_rqst structure and XDR buffers
269 * associated with this rpc_task.
270 */
271void xprt_free_bc_request(struct rpc_rqst *req)
272{
273 struct rpc_xprt *xprt = req->rq_xprt;
274
42e5c3e2
CL
275 xprt->ops->bc_free_rqst(req);
276}
277
278void xprt_free_bc_rqst(struct rpc_rqst *req)
279{
280 struct rpc_xprt *xprt = req->rq_xprt;
281
fb7a0b9a
RL
282 dprintk("RPC: free backchannel req=%p\n", req);
283
2ea24497 284 req->rq_connect_cookie = xprt->connect_cookie - 1;
4e857c58 285 smp_mb__before_atomic();
fb7a0b9a 286 clear_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
4e857c58 287 smp_mb__after_atomic();
fb7a0b9a 288
0d2a970d
TM
289 /*
290 * Return it to the list of preallocations so that it
291 * may be reused by a new callback request.
292 */
293 spin_lock_bh(&xprt->bc_pa_lock);
294 if (xprt_need_to_requeue(xprt)) {
295 list_add_tail(&req->rq_bc_pa_list, &xprt->bc_pa_list);
296 xprt->bc_alloc_count++;
7402a4fe 297 atomic_inc(&xprt->bc_slot_count);
0d2a970d
TM
298 req = NULL;
299 }
300 spin_unlock_bh(&xprt->bc_pa_lock);
301 if (req != NULL) {
fb7a0b9a
RL
302 /*
303 * The last remaining session was destroyed while this
304 * entry was in use. Free the entry and don't attempt
305 * to add back to the list because there is no need to
306 * have anymore preallocated entries.
307 */
308 dprintk("RPC: Last session removed req=%p\n", req);
309 xprt_free_allocation(req);
fb7a0b9a 310 }
875f0706 311 xprt_put(xprt);
fb7a0b9a
RL
312}
313
2ea24497
TM
314/*
315 * One or more rpc_rqst structure have been preallocated during the
316 * backchannel setup. Buffer space for the send and private XDR buffers
317 * has been preallocated as well. Use xprt_alloc_bc_request to allocate
318 * to this request. Use xprt_free_bc_request to return it.
319 *
320 * We know that we're called in soft interrupt context, grab the spin_lock
321 * since there is no need to grab the bottom half spin_lock.
322 *
323 * Return an available rpc_rqst, otherwise NULL if non are available.
324 */
325struct rpc_rqst *xprt_lookup_bc_request(struct rpc_xprt *xprt, __be32 xid)
326{
0d1bf340
TM
327 struct rpc_rqst *req, *new = NULL;
328
329 do {
330 spin_lock(&xprt->bc_pa_lock);
331 list_for_each_entry(req, &xprt->bc_pa_list, rq_bc_pa_list) {
332 if (req->rq_connect_cookie != xprt->connect_cookie)
333 continue;
334 if (req->rq_xid == xid)
335 goto found;
336 }
337 req = xprt_get_bc_request(xprt, xid, new);
2ea24497 338found:
0d1bf340
TM
339 spin_unlock(&xprt->bc_pa_lock);
340 if (new) {
341 if (req != new)
875f0706 342 xprt_free_allocation(new);
0d1bf340
TM
343 break;
344 } else if (req)
345 break;
346 new = xprt_alloc_bc_req(xprt, GFP_KERNEL);
347 } while (new);
2ea24497
TM
348 return req;
349}
350
351/*
352 * Add callback request to callback list. The callback
353 * service sleeps on the sv_cb_waitq waiting for new
354 * requests. Wake it up after adding enqueing the
355 * request.
356 */
357void xprt_complete_bc_request(struct rpc_rqst *req, uint32_t copied)
358{
359 struct rpc_xprt *xprt = req->rq_xprt;
360 struct svc_serv *bc_serv = xprt->bc_serv;
361
813b00d6
CL
362 spin_lock(&xprt->bc_pa_lock);
363 list_del(&req->rq_bc_pa_list);
7402a4fe 364 xprt->bc_alloc_count--;
813b00d6
CL
365 spin_unlock(&xprt->bc_pa_lock);
366
2ea24497
TM
367 req->rq_private_buf.len = copied;
368 set_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
369
370 dprintk("RPC: add callback request to list\n");
875f0706 371 xprt_get(xprt);
2ea24497 372 spin_lock(&bc_serv->sv_cb_lock);
2ea24497
TM
373 list_add(&req->rq_bc_list, &bc_serv->sv_cb_list);
374 wake_up(&bc_serv->sv_cb_waitq);
375 spin_unlock(&bc_serv->sv_cb_lock);
376}