File: /usr/src/linux/drivers/s390/ccwcache.c
1 /*
2 * File...........: linux/drivers/s390/ccwcache.c
3 * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
4 * Martin Schiwdefsky <schwidefsky@de.ibm.com>
5 * Bugreports.to..: <Linux390@de.ibm.com>
6 * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 2000a
7
8 * History of changes
9 * 11/14/00 redesign by Martin Schwidefsky
10 */
11
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/version.h>
15
16 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2,3,98))
17 #include <linux/spinlock.h>
18 #else
19 #include <asm/spinlock.h>
20 #endif
21
22 #include <asm/debug.h>
23 #include <asm/ccwcache.h>
24 #include <asm/ebcdic.h>
25
26 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2,3,98))
27 #define CCW_CACHE_SLAB_TYPE (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA)
28 #define CCW_CACHE_TYPE (GFP_ATOMIC | GFP_DMA)
29 #else
30 #define CCW_CACHE_SLAB_TYPE (SLAB_HWCACHE_ALIGN)
31 #define CCW_CACHE_TYPE (GFP_ATOMIC)
32 #define kmem_cache_destroy(x) do {} while(0)
33 #endif
34
35 #undef PRINTK_HEADER
36 #define PRINTK_HEADER "ccwcache"
37
38 /* pointer to list of allocated requests */
39 static ccw_req_t *ccwreq_actual = NULL;
40 static spinlock_t ccwchain_lock;
41
42 /* pointer to debug area */
43 static debug_info_t *debug_area = NULL;
44
45 /* SECTION: Handling of the dynamically allocated kmem slabs */
46
47 /* a name template for the cache-names */
48 static char ccw_name_template[] = "ccwcache-\0\0\0\0"; /* fill name with zeroes! */
49 /* the cache's names */
50 static char ccw_cache_name[CCW_NUMBER_CACHES][sizeof(ccw_name_template)+1];
51 /* the caches itself*/
52 static kmem_cache_t *ccw_cache[CCW_NUMBER_CACHES];
53
54 /* SECTION: (de)allocation of ccw_req_t */
55
56 /*
57 * void enchain ( ccw_req_t *request )
58 * enchains the request to the ringbuffer
59 */
60 static inline void
61 enchain ( ccw_req_t *request )
62 {
63 unsigned long flags;
64
65 /* Sanity checks */
66 if ( request == NULL )
67 BUG();
68 spin_lock_irqsave(&ccwchain_lock,flags);
69 if ( ccwreq_actual == NULL ) { /* queue empty */
70 ccwreq_actual = request;
71 request->int_prev = ccwreq_actual;
72 request->int_next = ccwreq_actual;
73 } else {
74 request->int_next = ccwreq_actual;
75 request->int_prev = ccwreq_actual->int_prev;
76 request->int_prev->int_next = request;
77 request->int_next->int_prev = request;
78 }
79 spin_unlock_irqrestore(&ccwchain_lock,flags);
80 }
81
82 /*
83 * void dechain ( ccw_req_t *request )
84 * dechains the request from the ringbuffer
85 */
86 static inline void
87 dechain ( ccw_req_t *request )
88 {
89 unsigned long flags;
90
91 /* Sanity checks */
92 if ( request == NULL ||
93 request->int_next == NULL ||
94 request->int_prev == NULL)
95 BUG();
96 /* first deallocate request from list of allocates requests */
97 spin_lock_irqsave(&ccwchain_lock,flags);
98 if ( request -> int_next == request -> int_prev ) {
99 ccwreq_actual = NULL;
100 } else {
101 if ( ccwreq_actual == request ) {
102 ccwreq_actual = request->int_next;
103 }
104 request->int_prev->int_next = request->int_next;
105 request->int_next->int_prev = request->int_prev;
106 }
107 spin_unlock_irqrestore(&ccwchain_lock,flags);
108 }
109
110 /*
111 * ccw_req_t *ccw_alloc_request ( int cplength, int datasize )
112 * allocates a ccw_req_t, that
113 * - can hold a CP of cplength CCWS
114 * - can hold additional data up to datasize
115 */
116 ccw_req_t *
117 ccw_alloc_request ( char *magic, int cplength, int datasize )
118 {
119 ccw_req_t * request = NULL;
120 int size_needed;
121 int data_offset, ccw_offset;
122 int cachind;
123
124 /* Sanity checks */
125 if ( magic == NULL || datasize > PAGE_SIZE ||
126 cplength == 0 || (cplength*sizeof(ccw1_t)) > PAGE_SIZE)
127 BUG();
128 debug_text_event ( debug_area, 1, "ALLC");
129 debug_text_event ( debug_area, 1, magic);
130 debug_int_event ( debug_area, 1, cplength);
131 debug_int_event ( debug_area, 1, datasize);
132
133 /* We try to keep things together in memory */
134 size_needed = (sizeof (ccw_req_t) + 7) & -8;
135 data_offset = ccw_offset = 0;
136 if (size_needed + datasize <= PAGE_SIZE) {
137 /* Keep data with the request */
138 data_offset = size_needed;
139 size_needed += (datasize + 7) & -8;
140 }
141 if (size_needed + cplength*sizeof(ccw1_t) <= PAGE_SIZE) {
142 /* Keep CCWs with request */
143 ccw_offset = size_needed;
144 size_needed += cplength*sizeof(ccw1_t);
145 }
146
147 /* determine cache index for the requested size */
148 for (cachind = 0; cachind < CCW_NUMBER_CACHES; cachind ++ )
149 if ( size_needed < (SMALLEST_SLAB << cachind) )
150 break;
151
152 /* Try to fulfill the request from a cache */
153 if ( ccw_cache[cachind] == NULL )
154 BUG();
155 request = kmem_cache_alloc ( ccw_cache[cachind], CCW_CACHE_TYPE );
156 if (request == NULL)
157 return NULL;
158 memset ( request, 0, (SMALLEST_SLAB << cachind));
159 request->cache = ccw_cache[cachind];
160
161 /* Allocate memory for the extra data */
162 if (data_offset == 0) {
163 /* Allocated memory for extra data with kmalloc */
164 request->data = (void *) kmalloc(datasize, CCW_CACHE_TYPE );
165 if (request->data == NULL) {
166 printk(KERN_WARNING PRINTK_HEADER
167 "Couldn't allocate data area\n");
168 kmem_cache_free(request->cache, request);
169 return NULL;
170 }
171 } else
172 /* Extra data already allocated with the request */
173 request->data = (void *) ((addr_t) request + data_offset);
174
175 /* Allocate memory for the channel program */
176 if (ccw_offset == 0) {
177 /* Allocated memory for the channel program with kmalloc */
178 request->cpaddr = (ccw1_t *) kmalloc(cplength*sizeof(ccw1_t),
179 CCW_CACHE_TYPE);
180 if (request->cpaddr == NULL) {
181 printk (KERN_DEBUG PRINTK_HEADER
182 "Couldn't allocate ccw area\n");
183 if (data_offset == 0)
184 kfree(request->data);
185 kmem_cache_free(request->cache, request);
186 return NULL;
187 }
188 } else
189 /* Channel program already allocated with the request */
190 request->cpaddr = (ccw1_t *) ((addr_t) request + ccw_offset);
191
192 memset ( request->data, 0, datasize );
193 memset ( request->cpaddr, 0, cplength*sizeof(ccw1_t) );
194 strncpy ( (char *)(&request->magic), magic, 4);
195
196 ASCEBC((char *)(&request->magic),4);
197 request -> cplength = cplength;
198 request -> datasize = datasize;
199 /* enqueue request to list of allocated requests */
200 enchain(request);
201 debug_int_event ( debug_area, 1, (long)request);
202 return request;
203 }
204
205 /*
206 * void ccw_free_request ( ccw_req_t * )
207 * deallocates the ccw_req_t, given as argument
208 */
209
210 void
211 ccw_free_request ( ccw_req_t * request )
212 {
213 int size_needed;
214
215 debug_text_event ( debug_area, 1, "FREE");
216 debug_int_event ( debug_area, 1, (long)request);
217
218 /* Sanity checks */
219 if ( request == NULL || request->cache == NULL)
220 BUG();
221
222 dechain ( request);
223 /* Free memory allocated with kmalloc
224 * make the same decisions as in ccw_alloc_requets */
225 size_needed = (sizeof (ccw_req_t) + 7) & -8;
226 if (size_needed + request->datasize <= PAGE_SIZE)
227 /* We kept the data with the request */
228 size_needed += (request->datasize + 7) & -8;
229 else
230 kfree(request->data);
231 if (size_needed + request->cplength*sizeof(ccw1_t) > PAGE_SIZE)
232 /* We kept the CCWs with request */
233 kfree(request->cpaddr);
234 kmem_cache_free(request -> cache, request);
235 }
236
237 /* SECTION: initialization and cleanup functions */
238
239 /*
240 * ccwcache_init
241 * called as an initializer function for the ccw memory management
242 */
243
244 int
245 ccwcache_init (void)
246 {
247 int rc = 0;
248 int cachind;
249
250 /* initialize variables */
251 spin_lock_init(&ccwchain_lock);
252
253 /* allocate a debug area */
254 debug_area = debug_register( "ccwcache", 2, 4,sizeof(void*));
255 if ( debug_area == NULL )
256 BUG();
257
258 debug_register_view(debug_area,&debug_hex_ascii_view);
259 debug_register_view(debug_area,&debug_raw_view);
260 debug_text_event ( debug_area, 0, "INIT");
261
262 /* First allocate the kmem caches */
263 for ( cachind = 0; cachind < CCW_NUMBER_CACHES; cachind ++ ) {
264 int slabsize = SMALLEST_SLAB << cachind;
265 debug_text_event ( debug_area, 1, "allc");
266 debug_int_event ( debug_area, 1, slabsize);
267 sprintf ( ccw_cache_name[cachind],
268 "%s%d%c", ccw_name_template, slabsize, 0);
269 ccw_cache[cachind] =
270 kmem_cache_create( ccw_cache_name[cachind],
271 slabsize, 0,
272 CCW_CACHE_SLAB_TYPE,
273 NULL, NULL );
274 debug_int_event ( debug_area, 1, (long)ccw_cache[cachind]);
275 if (ccw_cache[cachind] == NULL)
276 panic ("Allocation of CCW cache failed\n");
277 }
278 return rc;
279 }
280
281 /*
282 * ccwcache_cleanup
283 * called as a cleanup function for the ccw memory management
284 */
285
286 void
287 ccwcache_cleanup (void)
288 {
289 int cachind;
290
291 /* Shrink the caches, if available */
292 for ( cachind = 0; cachind < CCW_NUMBER_CACHES; cachind ++ ) {
293 if ( ccw_cache[cachind] ) {
294 if ( kmem_cache_shrink(ccw_cache[cachind]) == 0 ) {
295 ccw_cache[cachind] = NULL;
296 }
297 kmem_cache_destroy(ccw_cache[cachind]);
298 }
299 }
300 debug_unregister( debug_area );
301 }
302
303 EXPORT_SYMBOL(ccw_alloc_request);
304 EXPORT_SYMBOL(ccw_free_request);
305
306