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fb7a0b9a RL |
1 | /****************************************************************************** |
2 | ||
3 | (c) 2007 Network Appliance, Inc. All Rights Reserved. | |
4 | (c) 2009 NetApp. All Rights Reserved. | |
5 | ||
6 | NetApp provides this source code under the GPL v2 License. | |
7 | The GPL v2 license is available at | |
8 | http://opensource.org/licenses/gpl-license.php. | |
9 | ||
10 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
11 | "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
12 | LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
13 | A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR | |
14 | CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, | |
15 | EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, | |
16 | PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR | |
17 | PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF | |
18 | LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING | |
19 | NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS | |
20 | SOFTWARE, 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 | ||
36 | unsigned 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 | */ | |
45 | static 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 | */ | |
54 | static 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 |
67 | static 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 | ||
78 | static | |
79 | struct 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; | |
104 | out_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 | |
114 | * the rpc_xprt. Anyone of these resources may be used used by an | |
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 | */ | |
127 | int 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 | } | |
133 | EXPORT_SYMBOL_GPL(xprt_setup_backchannel); | |
134 | ||
135 | int 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 | ||
181 | out_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 | */ |
206 | void 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 | } | |
211 | EXPORT_SYMBOL_GPL(xprt_destroy_backchannel); | |
212 | ||
213 | void 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); |
7402a4fe | 223 | xprt->bc_alloc_max -= max_reqs; |
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 | 235 | out: |
fb7a0b9a RL |
236 | dprintk("RPC: backchannel list empty= %s\n", |
237 | list_empty(&xprt->bc_pa_list) ? "true" : "false"); | |
238 | } | |
fb7a0b9a | 239 | |
0d1bf340 TM |
240 | static 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 | 263 | not_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 | */ | |
271 | void 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 | ||
278 | void 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); | |
310 | return; | |
311 | } | |
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 | */ | |
325 | struct 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 | 338 | found: |
0d1bf340 TM |
339 | spin_unlock(&xprt->bc_pa_lock); |
340 | if (new) { | |
341 | if (req != new) | |
342 | xprt_free_bc_rqst(new); | |
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 | */ | |
357 | void 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"); | |
371 | spin_lock(&bc_serv->sv_cb_lock); | |
2ea24497 TM |
372 | list_add(&req->rq_bc_list, &bc_serv->sv_cb_list); |
373 | wake_up(&bc_serv->sv_cb_waitq); | |
374 | spin_unlock(&bc_serv->sv_cb_lock); | |
375 | } |