[PATCH 2/12] random pt3: Static allocation of pools
From: Matt Mackall
Date: Wed Jan 19 2005 - 03:34:30 EST
As we no longer allow resizing of pools, it makes sense to allocate
and initialize them statically. Remove create_entropy_store and
simplify rand_initialize.
Signed-off-by: Matt Mackall <mpm@xxxxxxxxxxx>
Index: rnd/drivers/char/random.c
===================================================================
--- rnd.orig/drivers/char/random.c 2005-01-18 10:22:06.531748727 -0800
+++ rnd/drivers/char/random.c 2005-01-18 10:34:46.175902338 -0800
@@ -295,42 +295,37 @@
int poolwords;
int tap1, tap2, tap3, tap4, tap5;
} poolinfo_table[] = {
+ /* x^128 + x^103 + x^76 + x^51 +x^25 + x + 1 -- 105 */
+ { 128, 103, 76, 51, 25, 1 },
+ /* x^32 + x^26 + x^20 + x^14 + x^7 + x + 1 -- 15 */
+ { 32, 26, 20, 14, 7, 1 },
+#if 0
/* x^2048 + x^1638 + x^1231 + x^819 + x^411 + x + 1 -- 115 */
{ 2048, 1638, 1231, 819, 411, 1 },
/* x^1024 + x^817 + x^615 + x^412 + x^204 + x + 1 -- 290 */
{ 1024, 817, 615, 412, 204, 1 },
-#if 0 /* Alternate polynomial */
+
/* x^1024 + x^819 + x^616 + x^410 + x^207 + x^2 + 1 -- 115 */
{ 1024, 819, 616, 410, 207, 2 },
-#endif
/* x^512 + x^411 + x^308 + x^208 + x^104 + x + 1 -- 225 */
{ 512, 411, 308, 208, 104, 1 },
-#if 0 /* Alternates */
+
/* x^512 + x^409 + x^307 + x^206 + x^102 + x^2 + 1 -- 95 */
{ 512, 409, 307, 206, 102, 2 },
/* x^512 + x^409 + x^309 + x^205 + x^103 + x^2 + 1 -- 95 */
{ 512, 409, 309, 205, 103, 2 },
-#endif
/* x^256 + x^205 + x^155 + x^101 + x^52 + x + 1 -- 125 */
{ 256, 205, 155, 101, 52, 1 },
- /* x^128 + x^103 + x^76 + x^51 +x^25 + x + 1 -- 105 */
- { 128, 103, 76, 51, 25, 1 },
-#if 0 /* Alternate polynomial */
/* x^128 + x^103 + x^78 + x^51 + x^27 + x^2 + 1 -- 70 */
{ 128, 103, 78, 51, 27, 2 },
-#endif
/* x^64 + x^52 + x^39 + x^26 + x^14 + x + 1 -- 15 */
{ 64, 52, 39, 26, 14, 1 },
-
- /* x^32 + x^26 + x^20 + x^14 + x^7 + x + 1 -- 15 */
- { 32, 26, 20, 14, 7, 1 },
-
- { 0, 0, 0, 0, 0, 0 },
+#endif
};
#define POOLBITS poolwords*32
@@ -382,9 +377,6 @@
/*
* Static global variables
*/
-static struct entropy_store *input_pool; /* The default global store */
-static struct entropy_store *blocking_pool; /* secondary store */
-static struct entropy_store *nonblocking_pool; /* For urandom */
static DECLARE_WAIT_QUEUE_HEAD(random_read_wait);
static DECLARE_WAIT_QUEUE_HEAD(random_write_wait);
@@ -392,7 +384,8 @@
* Forward procedure declarations
*/
#ifdef CONFIG_SYSCTL
-static void sysctl_init_random(struct entropy_store *random_state);
+struct entropy_store;
+static void sysctl_init_random(struct entropy_store *pool);
#endif
static inline __u32 rol32(__u32 word, int shift)
@@ -406,9 +399,9 @@
#define DEBUG_ENT(fmt, arg...) do { if (debug) \
printk(KERN_DEBUG "random %04d %04d %04d: " \
fmt,\
- input_pool->entropy_count,\
- blocking_pool->entropy_count,\
- nonblocking_pool->entropy_count,\
+ input_pool.entropy_count,\
+ blocking_pool.entropy_count,\
+ nonblocking_pool.entropy_count,\
## arg); } while (0)
#else
#define DEBUG_ENT(fmt, arg...) do {} while (0)
@@ -423,7 +416,7 @@
struct entropy_store {
/* mostly-read data: */
- struct poolinfo poolinfo;
+ struct poolinfo *poolinfo;
__u32 *pool;
const char *name;
@@ -434,48 +427,30 @@
int input_rotate;
};
-/*
- * Initialize the entropy store. The input argument is the size of
- * the random pool.
- *
- * Returns an negative error if there is a problem.
- */
-static int create_entropy_store(int size, const char *name,
- struct entropy_store **ret_bucket)
-{
- struct entropy_store *r;
- struct poolinfo *p;
- int poolwords;
-
- poolwords = (size + 3) / 4; /* Convert bytes->words */
- /* The pool size must be a multiple of 16 32-bit words */
- poolwords = ((poolwords + 15) / 16) * 16;
+static __u32 input_pool_data[INPUT_POOL_WORDS];
+static __u32 blocking_pool_data[OUTPUT_POOL_WORDS];
+static __u32 nonblocking_pool_data[OUTPUT_POOL_WORDS];
+
+static struct entropy_store input_pool = {
+ .poolinfo = &poolinfo_table[0],
+ .name = "input",
+ .lock = SPIN_LOCK_UNLOCKED,
+ .pool = input_pool_data
+};
- for (p = poolinfo_table; p->poolwords; p++) {
- if (poolwords == p->poolwords)
- break;
- }
- if (p->poolwords == 0)
- return -EINVAL;
+static struct entropy_store blocking_pool = {
+ .poolinfo = &poolinfo_table[1],
+ .name = "blocking",
+ .lock = SPIN_LOCK_UNLOCKED,
+ .pool = blocking_pool_data
+};
- r = kmalloc(sizeof(struct entropy_store), GFP_KERNEL);
- if (!r)
- return -ENOMEM;
-
- memset (r, 0, sizeof(struct entropy_store));
- r->poolinfo = *p;
-
- r->pool = kmalloc(POOLBYTES, GFP_KERNEL);
- if (!r->pool) {
- kfree(r);
- return -ENOMEM;
- }
- memset(r->pool, 0, POOLBYTES);
- r->lock = SPIN_LOCK_UNLOCKED;
- r->name = name;
- *ret_bucket = r;
- return 0;
-}
+static struct entropy_store nonblocking_pool = {
+ .poolinfo = &poolinfo_table[1],
+ .name = "nonblocking",
+ .lock = SPIN_LOCK_UNLOCKED,
+ .pool = nonblocking_pool_data
+};
/*
* This function adds a byte into the entropy "pool". It does not
@@ -495,16 +470,16 @@
0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 };
unsigned long i, add_ptr, tap1, tap2, tap3, tap4, tap5;
int new_rotate, input_rotate;
- int wordmask = r->poolinfo.poolwords - 1;
+ int wordmask = r->poolinfo->poolwords - 1;
__u32 w, next_w;
unsigned long flags;
/* Taps are constant, so we can load them without holding r->lock. */
- tap1 = r->poolinfo.tap1;
- tap2 = r->poolinfo.tap2;
- tap3 = r->poolinfo.tap3;
- tap4 = r->poolinfo.tap4;
- tap5 = r->poolinfo.tap5;
+ tap1 = r->poolinfo->tap1;
+ tap2 = r->poolinfo->tap2;
+ tap3 = r->poolinfo->tap3;
+ tap4 = r->poolinfo->tap4;
+ tap5 = r->poolinfo->tap5;
next_w = *in++;
spin_lock_irqsave(&r->lock, flags);
@@ -570,8 +545,8 @@
DEBUG_ENT("negative entropy/overflow (%d+%d)\n",
r->entropy_count, nbits);
r->entropy_count = 0;
- } else if (r->entropy_count + nbits > r->poolinfo.POOLBITS) {
- r->entropy_count = r->poolinfo.POOLBITS;
+ } else if (r->entropy_count + nbits > r->poolinfo->POOLBITS) {
+ r->entropy_count = r->poolinfo->POOLBITS;
} else {
r->entropy_count += nbits;
if (nbits)
@@ -660,7 +635,7 @@
static void batch_entropy_process(void *private_)
{
struct entropy_store *r = (struct entropy_store *) private_, *p;
- int max_entropy = r->poolinfo.POOLBITS;
+ int max_entropy = r->poolinfo->POOLBITS;
unsigned head, tail;
/* Mixing into the pool is expensive, so copy over the batch
@@ -682,8 +657,9 @@
p = r;
while (head != tail) {
if (r->entropy_count >= max_entropy) {
- r = (r == blocking_pool) ? input_pool : blocking_pool;
- max_entropy = r->poolinfo.POOLBITS;
+ r = (r == &blocking_pool) ? &input_pool :
+ &blocking_pool;
+ max_entropy = r->poolinfo->POOLBITS;
}
add_entropy_words(r, batch_entropy_copy[tail].data, 2);
credit_entropy_store(r, batch_entropy_copy[tail].credit);
@@ -727,7 +703,7 @@
preempt_disable();
/* if over the trickle threshold, use only 1 in 4096 samples */
- if (input_pool->entropy_count > trickle_thresh &&
+ if (input_pool.entropy_count > trickle_thresh &&
(__get_cpu_var(trickle_count)++ & 0xfff))
goto out;
@@ -1226,7 +1202,7 @@
size_t nbytes, __u32 *tmp)
{
if (r->entropy_count < nbytes * 8 &&
- r->entropy_count < r->poolinfo.POOLBITS) {
+ r->entropy_count < r->poolinfo->POOLBITS) {
int bytes = max_t(int, random_read_wakeup_thresh / 8,
min_t(int, nbytes, TMP_BUF_SIZE));
@@ -1234,7 +1210,7 @@
"(%d of %d requested)\n",
r->name, bytes * 8, nbytes * 8, r->entropy_count);
- bytes=extract_entropy(input_pool, tmp, bytes,
+ bytes=extract_entropy(&input_pool, tmp, bytes,
EXTRACT_ENTROPY_LIMIT);
add_entropy_words(r, tmp, bytes);
credit_entropy_store(r, bytes*8);
@@ -1263,8 +1239,8 @@
unsigned long cpuflags;
/* Redundant, but just in case... */
- if (r->entropy_count > r->poolinfo.POOLBITS)
- r->entropy_count = r->poolinfo.POOLBITS;
+ if (r->entropy_count > r->poolinfo->POOLBITS)
+ r->entropy_count = r->poolinfo->POOLBITS;
if (flags & EXTRACT_ENTROPY_SECONDARY)
xfer_secondary_pool(r, nbytes, tmp);
@@ -1323,7 +1299,7 @@
* attempts to find previous ouputs), unless the hash
* function can be inverted.
*/
- for (i = 0, x = 0; i < r->poolinfo.poolwords; i += 16, x+=2) {
+ for (i = 0, x = 0; i < r->poolinfo->poolwords; i += 16, x+=2) {
HASH_TRANSFORM(tmp, r->pool+i);
add_entropy_words(r, &tmp[x%HASH_BUFFER_SIZE], 1);
}
@@ -1377,21 +1353,8 @@
*/
void get_random_bytes(void *buf, int nbytes)
{
- struct entropy_store *r = nonblocking_pool;
- int flags = EXTRACT_ENTROPY_SECONDARY;
-
- if (!r)
- r = blocking_pool;
- if (!r) {
- r = input_pool;
- flags = 0;
- }
- if (!r) {
- printk(KERN_NOTICE "get_random_bytes called before "
- "random driver initialization\n");
- return;
- }
- extract_entropy(r, (char *) buf, nbytes, flags);
+ extract_entropy(&nonblocking_pool, (char *) buf, nbytes,
+ EXTRACT_ENTROPY_SECONDARY);
}
EXPORT_SYMBOL(get_random_bytes);
@@ -1422,21 +1385,13 @@
static int __init rand_initialize(void)
{
- if (create_entropy_store(INPUT_POOL_WORDS, "input", &input_pool))
- goto err;
- if (batch_entropy_init(BATCH_ENTROPY_SIZE, input_pool))
- goto err;
- if (create_entropy_store(OUTPUT_POOL_WORDS, "blocking",
- &blocking_pool))
- goto err;
- if (create_entropy_store(OUTPUT_POOL_WORDS, "nonblocking",
- &nonblocking_pool))
+ if (batch_entropy_init(BATCH_ENTROPY_SIZE, &input_pool))
goto err;
- init_std_data(input_pool);
- init_std_data(blocking_pool);
- init_std_data(nonblocking_pool);
+ init_std_data(&input_pool);
+ init_std_data(&blocking_pool);
+ init_std_data(&nonblocking_pool);
#ifdef CONFIG_SYSCTL
- sysctl_init_random(input_pool);
+ sysctl_init_random(&input_pool);
#endif
return 0;
err:
@@ -1492,7 +1447,7 @@
DEBUG_ENT("reading %d bits\n", n*8);
- n = extract_entropy(blocking_pool, buf, n,
+ n = extract_entropy(&blocking_pool, buf, n,
EXTRACT_ENTROPY_USER |
EXTRACT_ENTROPY_LIMIT |
EXTRACT_ENTROPY_SECONDARY);
@@ -1509,7 +1464,7 @@
DEBUG_ENT("sleeping?\n");
wait_event_interruptible(random_read_wait,
- input_pool->entropy_count >=
+ input_pool.entropy_count >=
random_read_wakeup_thresh);
DEBUG_ENT("awake\n");
@@ -1549,12 +1504,12 @@
int flags = EXTRACT_ENTROPY_USER;
unsigned long cpuflags;
- spin_lock_irqsave(&input_pool->lock, cpuflags);
- if (input_pool->entropy_count > input_pool->poolinfo.POOLBITS)
+ spin_lock_irqsave(&input_pool.lock, cpuflags);
+ if (input_pool.entropy_count > input_pool.poolinfo->POOLBITS)
flags |= EXTRACT_ENTROPY_SECONDARY;
- spin_unlock_irqrestore(&input_pool->lock, cpuflags);
+ spin_unlock_irqrestore(&input_pool.lock, cpuflags);
- return extract_entropy(nonblocking_pool, buf, nbytes, flags);
+ return extract_entropy(&nonblocking_pool, buf, nbytes, flags);
}
static unsigned int
@@ -1565,9 +1520,9 @@
poll_wait(file, &random_read_wait, wait);
poll_wait(file, &random_write_wait, wait);
mask = 0;
- if (input_pool->entropy_count >= random_read_wakeup_thresh)
+ if (input_pool.entropy_count >= random_read_wakeup_thresh)
mask |= POLLIN | POLLRDNORM;
- if (input_pool->entropy_count < random_write_wakeup_thresh)
+ if (input_pool.entropy_count < random_write_wakeup_thresh)
mask |= POLLOUT | POLLWRNORM;
return mask;
}
@@ -1593,7 +1548,7 @@
c -= bytes;
p += bytes;
- add_entropy_words(input_pool, buf, (bytes + 3) / 4);
+ add_entropy_words(&input_pool, buf, (bytes + 3) / 4);
}
if (p == buffer) {
return (ssize_t)ret;
@@ -1614,7 +1569,7 @@
switch (cmd) {
case RNDGETENTCNT:
- ent_count = input_pool->entropy_count;
+ ent_count = input_pool.entropy_count;
if (put_user(ent_count, p))
return -EFAULT;
return 0;
@@ -1623,12 +1578,12 @@
return -EPERM;
if (get_user(ent_count, p))
return -EFAULT;
- credit_entropy_store(input_pool, ent_count);
+ credit_entropy_store(&input_pool, ent_count);
/*
* Wake up waiting processes if we have enough
* entropy.
*/
- if (input_pool->entropy_count >= random_read_wakeup_thresh)
+ if (input_pool.entropy_count >= random_read_wakeup_thresh)
wake_up_interruptible(&random_read_wait);
return 0;
case RNDADDENTROPY:
@@ -1644,12 +1599,12 @@
size, &file->f_pos);
if (retval < 0)
return retval;
- credit_entropy_store(input_pool, ent_count);
+ credit_entropy_store(&input_pool, ent_count);
/*
* Wake up waiting processes if we have enough
* entropy.
*/
- if (input_pool->entropy_count >= random_read_wakeup_thresh)
+ if (input_pool.entropy_count >= random_read_wakeup_thresh)
wake_up_interruptible(&random_read_wait);
return 0;
case RNDZAPENTCNT:
@@ -1657,9 +1612,9 @@
/* Clear the entropy pool counters. */
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- init_std_data(input_pool);
- init_std_data(blocking_pool);
- init_std_data(nonblocking_pool);
+ init_std_data(&input_pool);
+ init_std_data(&blocking_pool);
+ init_std_data(&nonblocking_pool);
return 0;
default:
return -EINVAL;
@@ -1842,7 +1797,7 @@
{
min_read_thresh = 8;
min_write_thresh = 0;
- max_read_thresh = max_write_thresh = pool->poolinfo.POOLBITS;
+ max_read_thresh = max_write_thresh = pool->poolinfo->POOLBITS;
random_table[1].data = &pool->entropy_count;
}
#endif /* CONFIG_SYSCTL */
-
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