~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/net/sunrpc/backchannel_rqst.c

Version: ~ [ linux-5.4.2 ] ~ [ linux-5.3.15 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.88 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.158 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.206 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.206 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.78 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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>
 25 #include <linux/slab.h>
 26 #include <linux/sunrpc/xprt.h>
 27 #include <linux/export.h>
 28 #include <linux/sunrpc/bc_xprt.h>
 29 
 30 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 31 #define RPCDBG_FACILITY RPCDBG_TRANS
 32 #endif
 33 
 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 {
 40         return xprt->bc_alloc_count > 0;
 41 }
 42 
 43 static inline void xprt_inc_alloc_count(struct rpc_xprt *xprt, unsigned int n)
 44 {
 45         xprt->bc_alloc_count += n;
 46 }
 47 
 48 static 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  */
 57 static 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);
 62         WARN_ON_ONCE(test_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state));
 63         xbufp = &req->rq_private_buf;
 64         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);
 67         kfree(req);
 68 }
 69 
 70 /*
 71  * Preallocate up to min_reqs structures and related buffers for use
 72  * by the backchannel.  This function can be called multiple times
 73  * when creating new sessions that use the same rpc_xprt.  The
 74  * preallocated buffers are added to the pool of resources used by
 75  * the rpc_xprt.  Anyone of these resources may be used used by an
 76  * incoming callback request.  It's up to the higher levels in the
 77  * stack to enforce that the maximum number of session slots is not
 78  * being exceeded.
 79  *
 80  * Some callback arguments can be large.  For example, a pNFS server
 81  * using multiple deviceids.  The list can be unbound, but the client
 82  * has the ability to tell the server the maximum size of the callback
 83  * requests.  Each deviceID is 16 bytes, so allocate one page
 84  * for the arguments to have enough room to receive a number of these
 85  * deviceIDs.  The NFS client indicates to the pNFS server that its
 86  * callback requests can be up to 4096 bytes in size.
 87  */
 88 int xprt_setup_backchannel(struct rpc_xprt *xprt, unsigned int min_reqs)
 89 {
 90         struct page *page_rcv = NULL, *page_snd = NULL;
 91         struct xdr_buf *xbufp = NULL;
 92         struct rpc_rqst *req, *tmp;
 93         struct list_head tmp_list;
 94         int i;
 95 
 96         dprintk("RPC:       setup backchannel transport\n");
 97 
 98         /*
 99          * We use a temporary list to keep track of the preallocated
100          * buffers.  Once we're done building the list we splice it
101          * into the backchannel preallocation list off of the rpc_xprt
102          * struct.  This helps minimize the amount of time the list
103          * lock is held on the rpc_xprt struct.  It also makes cleanup
104          * easier in case of memory allocation errors.
105          */
106         INIT_LIST_HEAD(&tmp_list);
107         for (i = 0; i < min_reqs; i++) {
108                 /* Pre-allocate one backchannel rpc_rqst */
109                 req = kzalloc(sizeof(struct rpc_rqst), GFP_KERNEL);
110                 if (req == NULL) {
111                         printk(KERN_ERR "Failed to create bc rpc_rqst\n");
112                         goto out_free;
113                 }
114 
115                 /* Add the allocated buffer to the tmp list */
116                 dprintk("RPC:       adding req= %p\n", req);
117                 list_add(&req->rq_bc_pa_list, &tmp_list);
118 
119                 req->rq_xprt = xprt;
120                 INIT_LIST_HEAD(&req->rq_list);
121                 INIT_LIST_HEAD(&req->rq_bc_list);
122 
123                 /* Preallocate one XDR receive buffer */
124                 page_rcv = alloc_page(GFP_KERNEL);
125                 if (page_rcv == NULL) {
126                         printk(KERN_ERR "Failed to create bc receive xbuf\n");
127                         goto out_free;
128                 }
129                 xbufp = &req->rq_rcv_buf;
130                 xbufp->head[0].iov_base = page_address(page_rcv);
131                 xbufp->head[0].iov_len = PAGE_SIZE;
132                 xbufp->tail[0].iov_base = NULL;
133                 xbufp->tail[0].iov_len = 0;
134                 xbufp->page_len = 0;
135                 xbufp->len = PAGE_SIZE;
136                 xbufp->buflen = PAGE_SIZE;
137 
138                 /* Preallocate one XDR send buffer */
139                 page_snd = alloc_page(GFP_KERNEL);
140                 if (page_snd == NULL) {
141                         printk(KERN_ERR "Failed to create bc snd xbuf\n");
142                         goto out_free;
143                 }
144 
145                 xbufp = &req->rq_snd_buf;
146                 xbufp->head[0].iov_base = page_address(page_snd);
147                 xbufp->head[0].iov_len = 0;
148                 xbufp->tail[0].iov_base = NULL;
149                 xbufp->tail[0].iov_len = 0;
150                 xbufp->page_len = 0;
151                 xbufp->len = 0;
152                 xbufp->buflen = PAGE_SIZE;
153         }
154 
155         /*
156          * Add the temporary list to the backchannel preallocation list
157          */
158         spin_lock_bh(&xprt->bc_pa_lock);
159         list_splice(&tmp_list, &xprt->bc_pa_list);
160         xprt_inc_alloc_count(xprt, min_reqs);
161         spin_unlock_bh(&xprt->bc_pa_lock);
162 
163         dprintk("RPC:       setup backchannel transport done\n");
164         return 0;
165 
166 out_free:
167         /*
168          * Memory allocation failed, free the temporary list
169          */
170         list_for_each_entry_safe(req, tmp, &tmp_list, rq_bc_pa_list) {
171                 list_del(&req->rq_bc_pa_list);
172                 xprt_free_allocation(req);
173         }
174 
175         dprintk("RPC:       setup backchannel transport failed\n");
176         return -ENOMEM;
177 }
178 EXPORT_SYMBOL_GPL(xprt_setup_backchannel);
179 
180 /**
181  * xprt_destroy_backchannel - Destroys the backchannel preallocated structures.
182  * @xprt:       the transport holding the preallocated strucures
183  * @max_reqs    the maximum number of preallocated structures to destroy
184  *
185  * Since these structures may have been allocated by multiple calls
186  * to xprt_setup_backchannel, we only destroy up to the maximum number
187  * of reqs specified by the caller.
188  */
189 void xprt_destroy_backchannel(struct rpc_xprt *xprt, unsigned int max_reqs)
190 {
191         struct rpc_rqst *req = NULL, *tmp = NULL;
192 
193         dprintk("RPC:        destroy backchannel transport\n");
194 
195         if (max_reqs == 0)
196                 goto out;
197 
198         spin_lock_bh(&xprt->bc_pa_lock);
199         xprt_dec_alloc_count(xprt, max_reqs);
200         list_for_each_entry_safe(req, tmp, &xprt->bc_pa_list, rq_bc_pa_list) {
201                 dprintk("RPC:        req=%p\n", req);
202                 list_del(&req->rq_bc_pa_list);
203                 xprt_free_allocation(req);
204                 if (--max_reqs == 0)
205                         break;
206         }
207         spin_unlock_bh(&xprt->bc_pa_lock);
208 
209 out:
210         dprintk("RPC:        backchannel list empty= %s\n",
211                 list_empty(&xprt->bc_pa_list) ? "true" : "false");
212 }
213 EXPORT_SYMBOL_GPL(xprt_destroy_backchannel);
214 
215 static struct rpc_rqst *xprt_alloc_bc_request(struct rpc_xprt *xprt, __be32 xid)
216 {
217         struct rpc_rqst *req = NULL;
218 
219         dprintk("RPC:       allocate a backchannel request\n");
220         if (list_empty(&xprt->bc_pa_list))
221                 goto not_found;
222 
223         req = list_first_entry(&xprt->bc_pa_list, struct rpc_rqst,
224                                 rq_bc_pa_list);
225         req->rq_reply_bytes_recvd = 0;
226         req->rq_bytes_sent = 0;
227         memcpy(&req->rq_private_buf, &req->rq_rcv_buf,
228                         sizeof(req->rq_private_buf));
229         req->rq_xid = xid;
230         req->rq_connect_cookie = xprt->connect_cookie;
231 not_found:
232         dprintk("RPC:       backchannel req=%p\n", req);
233         return req;
234 }
235 
236 /*
237  * Return the preallocated rpc_rqst structure and XDR buffers
238  * associated with this rpc_task.
239  */
240 void xprt_free_bc_request(struct rpc_rqst *req)
241 {
242         struct rpc_xprt *xprt = req->rq_xprt;
243 
244         dprintk("RPC:       free backchannel req=%p\n", req);
245 
246         req->rq_connect_cookie = xprt->connect_cookie - 1;
247         smp_mb__before_atomic();
248         WARN_ON_ONCE(!test_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state));
249         clear_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
250         smp_mb__after_atomic();
251 
252         if (!xprt_need_to_requeue(xprt)) {
253                 /*
254                  * The last remaining session was destroyed while this
255                  * entry was in use.  Free the entry and don't attempt
256                  * to add back to the list because there is no need to
257                  * have anymore preallocated entries.
258                  */
259                 dprintk("RPC:       Last session removed req=%p\n", req);
260                 xprt_free_allocation(req);
261                 return;
262         }
263 
264         /*
265          * Return it to the list of preallocations so that it
266          * may be reused by a new callback request.
267          */
268         spin_lock_bh(&xprt->bc_pa_lock);
269         list_add_tail(&req->rq_bc_pa_list, &xprt->bc_pa_list);
270         spin_unlock_bh(&xprt->bc_pa_lock);
271 }
272 
273 /*
274  * One or more rpc_rqst structure have been preallocated during the
275  * backchannel setup.  Buffer space for the send and private XDR buffers
276  * has been preallocated as well.  Use xprt_alloc_bc_request to allocate
277  * to this request.  Use xprt_free_bc_request to return it.
278  *
279  * We know that we're called in soft interrupt context, grab the spin_lock
280  * since there is no need to grab the bottom half spin_lock.
281  *
282  * Return an available rpc_rqst, otherwise NULL if non are available.
283  */
284 struct rpc_rqst *xprt_lookup_bc_request(struct rpc_xprt *xprt, __be32 xid)
285 {
286         struct rpc_rqst *req;
287 
288         spin_lock(&xprt->bc_pa_lock);
289         list_for_each_entry(req, &xprt->bc_pa_list, rq_bc_pa_list) {
290                 if (req->rq_connect_cookie != xprt->connect_cookie)
291                         continue;
292                 if (req->rq_xid == xid)
293                         goto found;
294         }
295         req = xprt_alloc_bc_request(xprt, xid);
296 found:
297         spin_unlock(&xprt->bc_pa_lock);
298         return req;
299 }
300 
301 /*
302  * Add callback request to callback list.  The callback
303  * service sleeps on the sv_cb_waitq waiting for new
304  * requests.  Wake it up after adding enqueing the
305  * request.
306  */
307 void xprt_complete_bc_request(struct rpc_rqst *req, uint32_t copied)
308 {
309         struct rpc_xprt *xprt = req->rq_xprt;
310         struct svc_serv *bc_serv = xprt->bc_serv;
311 
312         spin_lock(&xprt->bc_pa_lock);
313         list_del(&req->rq_bc_pa_list);
314         spin_unlock(&xprt->bc_pa_lock);
315 
316         req->rq_private_buf.len = copied;
317         set_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
318 
319         dprintk("RPC:       add callback request to list\n");
320         spin_lock(&bc_serv->sv_cb_lock);
321         list_add(&req->rq_bc_list, &bc_serv->sv_cb_list);
322         wake_up(&bc_serv->sv_cb_waitq);
323         spin_unlock(&bc_serv->sv_cb_lock);
324 }
325 
326 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp