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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 | ||
fb7a0b9a RL |
34 | /* |
35 | * Helper routines that track the number of preallocation elements | |
36 | * on the transport. | |
37 | */ | |
38 | static inline int xprt_need_to_requeue(struct rpc_xprt *xprt) | |
39 | { | |
0d2a970d | 40 | return xprt->bc_alloc_count < atomic_read(&xprt->bc_free_slots); |
fb7a0b9a RL |
41 | } |
42 | ||
43 | static inline void xprt_inc_alloc_count(struct rpc_xprt *xprt, unsigned int n) | |
44 | { | |
0d2a970d | 45 | atomic_add(n, &xprt->bc_free_slots); |
fb7a0b9a RL |
46 | xprt->bc_alloc_count += n; |
47 | } | |
48 | ||
49 | static inline int xprt_dec_alloc_count(struct rpc_xprt *xprt, unsigned int n) | |
50 | { | |
0d2a970d | 51 | atomic_sub(n, &xprt->bc_free_slots); |
fb7a0b9a RL |
52 | return xprt->bc_alloc_count -= n; |
53 | } | |
54 | ||
55 | /* | |
56 | * Free the preallocated rpc_rqst structure and the memory | |
57 | * buffers hanging off of it. | |
58 | */ | |
59 | static void xprt_free_allocation(struct rpc_rqst *req) | |
60 | { | |
61 | struct xdr_buf *xbufp; | |
62 | ||
63 | dprintk("RPC: free allocations for req= %p\n", req); | |
f30dfbba | 64 | WARN_ON_ONCE(test_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state)); |
88de6af2 | 65 | xbufp = &req->rq_rcv_buf; |
fb7a0b9a RL |
66 | free_page((unsigned long)xbufp->head[0].iov_base); |
67 | xbufp = &req->rq_snd_buf; | |
68 | free_page((unsigned long)xbufp->head[0].iov_base); | |
fb7a0b9a RL |
69 | kfree(req); |
70 | } | |
71 | ||
1dddda86 TM |
72 | static int xprt_alloc_xdr_buf(struct xdr_buf *buf, gfp_t gfp_flags) |
73 | { | |
74 | struct page *page; | |
75 | /* Preallocate one XDR receive buffer */ | |
76 | page = alloc_page(gfp_flags); | |
77 | if (page == NULL) | |
78 | return -ENOMEM; | |
79 | buf->head[0].iov_base = page_address(page); | |
80 | buf->head[0].iov_len = PAGE_SIZE; | |
81 | buf->tail[0].iov_base = NULL; | |
82 | buf->tail[0].iov_len = 0; | |
83 | buf->page_len = 0; | |
84 | buf->len = 0; | |
85 | buf->buflen = PAGE_SIZE; | |
86 | return 0; | |
87 | } | |
88 | ||
89 | static | |
90 | struct rpc_rqst *xprt_alloc_bc_req(struct rpc_xprt *xprt, gfp_t gfp_flags) | |
91 | { | |
92 | struct rpc_rqst *req; | |
93 | ||
94 | /* Pre-allocate one backchannel rpc_rqst */ | |
95 | req = kzalloc(sizeof(*req), gfp_flags); | |
96 | if (req == NULL) | |
97 | return NULL; | |
98 | ||
99 | req->rq_xprt = xprt; | |
100 | INIT_LIST_HEAD(&req->rq_list); | |
101 | INIT_LIST_HEAD(&req->rq_bc_list); | |
102 | ||
103 | /* Preallocate one XDR receive buffer */ | |
104 | if (xprt_alloc_xdr_buf(&req->rq_rcv_buf, gfp_flags) < 0) { | |
105 | printk(KERN_ERR "Failed to create bc receive xbuf\n"); | |
106 | goto out_free; | |
107 | } | |
108 | req->rq_rcv_buf.len = PAGE_SIZE; | |
109 | ||
110 | /* Preallocate one XDR send buffer */ | |
111 | if (xprt_alloc_xdr_buf(&req->rq_snd_buf, gfp_flags) < 0) { | |
112 | printk(KERN_ERR "Failed to create bc snd xbuf\n"); | |
113 | goto out_free; | |
114 | } | |
115 | return req; | |
116 | out_free: | |
117 | xprt_free_allocation(req); | |
118 | return NULL; | |
119 | } | |
120 | ||
fb7a0b9a RL |
121 | /* |
122 | * Preallocate up to min_reqs structures and related buffers for use | |
123 | * by the backchannel. This function can be called multiple times | |
124 | * when creating new sessions that use the same rpc_xprt. The | |
125 | * preallocated buffers are added to the pool of resources used by | |
126 | * the rpc_xprt. Anyone of these resources may be used used by an | |
127 | * incoming callback request. It's up to the higher levels in the | |
128 | * stack to enforce that the maximum number of session slots is not | |
129 | * being exceeded. | |
130 | * | |
131 | * Some callback arguments can be large. For example, a pNFS server | |
132 | * using multiple deviceids. The list can be unbound, but the client | |
133 | * has the ability to tell the server the maximum size of the callback | |
134 | * requests. Each deviceID is 16 bytes, so allocate one page | |
135 | * for the arguments to have enough room to receive a number of these | |
136 | * deviceIDs. The NFS client indicates to the pNFS server that its | |
137 | * callback requests can be up to 4096 bytes in size. | |
138 | */ | |
139 | int xprt_setup_backchannel(struct rpc_xprt *xprt, unsigned int min_reqs) | |
140 | { | |
1dddda86 | 141 | struct rpc_rqst *req; |
fb7a0b9a RL |
142 | struct list_head tmp_list; |
143 | int i; | |
144 | ||
145 | dprintk("RPC: setup backchannel transport\n"); | |
146 | ||
147 | /* | |
148 | * We use a temporary list to keep track of the preallocated | |
149 | * buffers. Once we're done building the list we splice it | |
150 | * into the backchannel preallocation list off of the rpc_xprt | |
151 | * struct. This helps minimize the amount of time the list | |
152 | * lock is held on the rpc_xprt struct. It also makes cleanup | |
153 | * easier in case of memory allocation errors. | |
154 | */ | |
155 | INIT_LIST_HEAD(&tmp_list); | |
156 | for (i = 0; i < min_reqs; i++) { | |
157 | /* Pre-allocate one backchannel rpc_rqst */ | |
1dddda86 | 158 | req = xprt_alloc_bc_req(xprt, GFP_KERNEL); |
fb7a0b9a RL |
159 | if (req == NULL) { |
160 | printk(KERN_ERR "Failed to create bc rpc_rqst\n"); | |
161 | goto out_free; | |
162 | } | |
163 | ||
164 | /* Add the allocated buffer to the tmp list */ | |
165 | dprintk("RPC: adding req= %p\n", req); | |
166 | list_add(&req->rq_bc_pa_list, &tmp_list); | |
fb7a0b9a RL |
167 | } |
168 | ||
169 | /* | |
170 | * Add the temporary list to the backchannel preallocation list | |
171 | */ | |
172 | spin_lock_bh(&xprt->bc_pa_lock); | |
173 | list_splice(&tmp_list, &xprt->bc_pa_list); | |
174 | xprt_inc_alloc_count(xprt, min_reqs); | |
175 | spin_unlock_bh(&xprt->bc_pa_lock); | |
176 | ||
177 | dprintk("RPC: setup backchannel transport done\n"); | |
178 | return 0; | |
179 | ||
180 | out_free: | |
181 | /* | |
182 | * Memory allocation failed, free the temporary list | |
183 | */ | |
1dddda86 TM |
184 | while (!list_empty(&tmp_list)) { |
185 | req = list_first_entry(&tmp_list, | |
186 | struct rpc_rqst, | |
187 | rq_bc_pa_list); | |
62835679 | 188 | list_del(&req->rq_bc_pa_list); |
fb7a0b9a | 189 | xprt_free_allocation(req); |
62835679 | 190 | } |
fb7a0b9a RL |
191 | |
192 | dprintk("RPC: setup backchannel transport failed\n"); | |
d24bab93 | 193 | return -ENOMEM; |
fb7a0b9a | 194 | } |
0d961aa9 | 195 | EXPORT_SYMBOL_GPL(xprt_setup_backchannel); |
fb7a0b9a | 196 | |
2c53040f BH |
197 | /** |
198 | * xprt_destroy_backchannel - Destroys the backchannel preallocated structures. | |
199 | * @xprt: the transport holding the preallocated strucures | |
200 | * @max_reqs the maximum number of preallocated structures to destroy | |
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) | |
207 | { | |
208 | struct rpc_rqst *req = NULL, *tmp = NULL; | |
209 | ||
210 | dprintk("RPC: destroy backchannel transport\n"); | |
211 | ||
c4ded8d9 WAA |
212 | if (max_reqs == 0) |
213 | goto out; | |
214 | ||
fb7a0b9a RL |
215 | spin_lock_bh(&xprt->bc_pa_lock); |
216 | xprt_dec_alloc_count(xprt, max_reqs); | |
217 | list_for_each_entry_safe(req, tmp, &xprt->bc_pa_list, rq_bc_pa_list) { | |
218 | dprintk("RPC: req=%p\n", req); | |
62835679 | 219 | list_del(&req->rq_bc_pa_list); |
fb7a0b9a RL |
220 | xprt_free_allocation(req); |
221 | if (--max_reqs == 0) | |
222 | break; | |
223 | } | |
224 | spin_unlock_bh(&xprt->bc_pa_lock); | |
225 | ||
c4ded8d9 | 226 | out: |
fb7a0b9a RL |
227 | dprintk("RPC: backchannel list empty= %s\n", |
228 | list_empty(&xprt->bc_pa_list) ? "true" : "false"); | |
229 | } | |
0d961aa9 | 230 | EXPORT_SYMBOL_GPL(xprt_destroy_backchannel); |
fb7a0b9a | 231 | |
2ea24497 | 232 | static struct rpc_rqst *xprt_alloc_bc_request(struct rpc_xprt *xprt, __be32 xid) |
fb7a0b9a | 233 | { |
2ea24497 | 234 | struct rpc_rqst *req = NULL; |
fb7a0b9a RL |
235 | |
236 | dprintk("RPC: allocate a backchannel request\n"); | |
0d2a970d | 237 | if (atomic_read(&xprt->bc_free_slots) <= 0) |
2ea24497 | 238 | goto not_found; |
0d2a970d TM |
239 | if (list_empty(&xprt->bc_pa_list)) { |
240 | req = xprt_alloc_bc_req(xprt, GFP_ATOMIC); | |
241 | if (!req) | |
242 | goto not_found; | |
68514471 TM |
243 | list_add_tail(&req->rq_bc_pa_list, &xprt->bc_pa_list); |
244 | xprt->bc_alloc_count++; | |
0d2a970d | 245 | } |
2ea24497 TM |
246 | req = list_first_entry(&xprt->bc_pa_list, struct rpc_rqst, |
247 | rq_bc_pa_list); | |
248 | req->rq_reply_bytes_recvd = 0; | |
249 | req->rq_bytes_sent = 0; | |
250 | memcpy(&req->rq_private_buf, &req->rq_rcv_buf, | |
fb7a0b9a | 251 | sizeof(req->rq_private_buf)); |
2ea24497 TM |
252 | req->rq_xid = xid; |
253 | req->rq_connect_cookie = xprt->connect_cookie; | |
254 | not_found: | |
fb7a0b9a RL |
255 | dprintk("RPC: backchannel req=%p\n", req); |
256 | return req; | |
257 | } | |
258 | ||
259 | /* | |
260 | * Return the preallocated rpc_rqst structure and XDR buffers | |
261 | * associated with this rpc_task. | |
262 | */ | |
263 | void xprt_free_bc_request(struct rpc_rqst *req) | |
264 | { | |
265 | struct rpc_xprt *xprt = req->rq_xprt; | |
266 | ||
267 | dprintk("RPC: free backchannel req=%p\n", req); | |
268 | ||
2ea24497 | 269 | req->rq_connect_cookie = xprt->connect_cookie - 1; |
4e857c58 | 270 | smp_mb__before_atomic(); |
fb7a0b9a | 271 | clear_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state); |
4e857c58 | 272 | smp_mb__after_atomic(); |
fb7a0b9a | 273 | |
0d2a970d TM |
274 | /* |
275 | * Return it to the list of preallocations so that it | |
276 | * may be reused by a new callback request. | |
277 | */ | |
278 | spin_lock_bh(&xprt->bc_pa_lock); | |
279 | if (xprt_need_to_requeue(xprt)) { | |
280 | list_add_tail(&req->rq_bc_pa_list, &xprt->bc_pa_list); | |
281 | xprt->bc_alloc_count++; | |
282 | req = NULL; | |
283 | } | |
284 | spin_unlock_bh(&xprt->bc_pa_lock); | |
285 | if (req != NULL) { | |
fb7a0b9a RL |
286 | /* |
287 | * The last remaining session was destroyed while this | |
288 | * entry was in use. Free the entry and don't attempt | |
289 | * to add back to the list because there is no need to | |
290 | * have anymore preallocated entries. | |
291 | */ | |
292 | dprintk("RPC: Last session removed req=%p\n", req); | |
293 | xprt_free_allocation(req); | |
294 | return; | |
295 | } | |
fb7a0b9a RL |
296 | } |
297 | ||
2ea24497 TM |
298 | /* |
299 | * One or more rpc_rqst structure have been preallocated during the | |
300 | * backchannel setup. Buffer space for the send and private XDR buffers | |
301 | * has been preallocated as well. Use xprt_alloc_bc_request to allocate | |
302 | * to this request. Use xprt_free_bc_request to return it. | |
303 | * | |
304 | * We know that we're called in soft interrupt context, grab the spin_lock | |
305 | * since there is no need to grab the bottom half spin_lock. | |
306 | * | |
307 | * Return an available rpc_rqst, otherwise NULL if non are available. | |
308 | */ | |
309 | struct rpc_rqst *xprt_lookup_bc_request(struct rpc_xprt *xprt, __be32 xid) | |
310 | { | |
311 | struct rpc_rqst *req; | |
312 | ||
313 | spin_lock(&xprt->bc_pa_lock); | |
314 | list_for_each_entry(req, &xprt->bc_pa_list, rq_bc_pa_list) { | |
315 | if (req->rq_connect_cookie != xprt->connect_cookie) | |
316 | continue; | |
317 | if (req->rq_xid == xid) | |
318 | goto found; | |
319 | } | |
320 | req = xprt_alloc_bc_request(xprt, xid); | |
321 | found: | |
322 | spin_unlock(&xprt->bc_pa_lock); | |
323 | return req; | |
324 | } | |
325 | ||
326 | /* | |
327 | * Add callback request to callback list. The callback | |
328 | * service sleeps on the sv_cb_waitq waiting for new | |
329 | * requests. Wake it up after adding enqueing the | |
330 | * request. | |
331 | */ | |
332 | void xprt_complete_bc_request(struct rpc_rqst *req, uint32_t copied) | |
333 | { | |
334 | struct rpc_xprt *xprt = req->rq_xprt; | |
335 | struct svc_serv *bc_serv = xprt->bc_serv; | |
336 | ||
813b00d6 CL |
337 | spin_lock(&xprt->bc_pa_lock); |
338 | list_del(&req->rq_bc_pa_list); | |
1980bd4d | 339 | xprt_dec_alloc_count(xprt, 1); |
813b00d6 CL |
340 | spin_unlock(&xprt->bc_pa_lock); |
341 | ||
2ea24497 TM |
342 | req->rq_private_buf.len = copied; |
343 | set_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state); | |
344 | ||
345 | dprintk("RPC: add callback request to list\n"); | |
346 | spin_lock(&bc_serv->sv_cb_lock); | |
2ea24497 TM |
347 | list_add(&req->rq_bc_list, &bc_serv->sv_cb_list); |
348 | wake_up(&bc_serv->sv_cb_waitq); | |
349 | spin_unlock(&bc_serv->sv_cb_lock); | |
350 | } | |
351 |