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7882 Add /dev/full , the always-full memory device
Reviewed by: Adam Stevko <adam.stevko@gmail.com>
Reviewed by: Toomas Soome <tsoome@me.com>
*** 23,32 ****
--- 23,33 ----
* Use is subject to license terms.
*/
/*
* Copyright (c) 2015, Joyent, Inc. All rights reserved.
+ * Copyright 2017 James S Blachly, MD <james.blachly@gmail.com>
*/
/*
* Memory special file
*/
*** 158,167 ****
--- 159,169 ----
{ "mem", M_MEM, 0, NULL, "all", 0640 },
{ "kmem", M_KMEM, 0, NULL, "all", 0640 },
{ "allkmem", M_ALLKMEM, 0, "all", "all", 0600 },
{ "null", M_NULL, PRIVONLY_DEV, NULL, NULL, 0666 },
{ "zero", M_ZERO, PRIVONLY_DEV, NULL, NULL, 0666 },
+ { "full", M_FULL, PRIVONLY_DEV, NULL, NULL, 0666 },
};
kstat_t *ksp;
mutex_init(&mm_lock, NULL, MUTEX_DEFAULT, NULL);
mm_map = vmem_alloc(heap_arena, PAGESIZE, VM_SLEEP);
*** 219,228 ****
--- 221,231 ----
mmopen(dev_t *devp, int flag, int typ, struct cred *cred)
{
switch (getminor(*devp)) {
case M_NULL:
case M_ZERO:
+ case M_FULL:
case M_MEM:
case M_KMEM:
case M_ALLKMEM:
/* standard devices */
break;
*** 245,254 ****
--- 248,258 ----
struct pollhead **phpp)
{
switch (getminor(dev)) {
case M_NULL:
case M_ZERO:
+ case M_FULL:
case M_MEM:
case M_KMEM:
case M_ALLKMEM:
*reventsp = events & (POLLIN | POLLOUT | POLLPRI | POLLRDNORM |
POLLWRNORM | POLLRDBAND | POLLWRBAND);
*** 436,445 ****
--- 440,457 ----
S_WRITE);
}
break;
+ case M_FULL:
+ if (rw == UIO_WRITE) {
+ error = ENOSPC;
+ break;
+ }
+ /* else it's a read, fall through to zero case */
+ /*FALLTHROUGH*/
+
case M_ZERO:
if (rw == UIO_READ) {
label_t ljb;
if (on_fault(&ljb)) {
*** 825,834 ****
--- 837,847 ----
case M_KMEM:
case M_ALLKMEM:
/* no longer supported with KPR */
return (-1);
+ case M_FULL:
case M_ZERO:
/*
* We shouldn't be mmap'ing to /dev/zero here as
* mmsegmap() should have already converted
* a mapping request for this device to a mapping