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Support discard in "block" and "swapon" #13

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Support discard in "block" and "swapon" #13

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ac8e912
block: define swap flags for block and swapon
mstorchak Jul 20, 2025
d6c6701
block: support discard in block
mstorchak Jul 20, 2025
ef7c9a5
block: add discard support to swapon
mstorchak Jul 19, 2025
123f0ec
block: enable discard in swapon -a
mstorchak Jul 20, 2025
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63 changes: 54 additions & 9 deletions block.c
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Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,16 @@
#include "libubi/libubi.h"
#endif

#ifndef SWAP_FLAG_DISCARD
#define SWAP_FLAG_DISCARD 0x10000
#endif
#ifndef SWAP_FLAG_DISCARD_ONCE
#define SWAP_FLAG_DISCARD_ONCE 0x20000
#endif
#ifndef SWAP_FLAG_DISCARD_PAGES
#define SWAP_FLAG_DISCARD_PAGES 0x40000
#endif

enum {
TYPE_MOUNT,
TYPE_SWAP,
Expand Down Expand Up @@ -143,6 +153,7 @@ enum {
SWAP_LABEL,
SWAP_DEVICE,
SWAP_PRIO,
SWAP_DISCARD,
__SWAP_MAX
};

Expand All @@ -152,6 +163,7 @@ static const struct blobmsg_policy swap_policy[__SWAP_MAX] = {
[SWAP_LABEL] = { .name = "label", .type = BLOBMSG_TYPE_STRING },
[SWAP_DEVICE] = { .name = "device", .type = BLOBMSG_TYPE_STRING },
[SWAP_PRIO] = { .name = "priority", .type = BLOBMSG_TYPE_INT32 },
[SWAP_DISCARD] = { .name = "discard", .type = BLOBMSG_TYPE_STRING },
};

static const struct uci_blob_param_list swap_attr_list = {
Expand Down Expand Up @@ -307,6 +319,7 @@ static int swap_add(struct uci_section *s)
{
struct blob_attr *tb[__SWAP_MAX] = { 0 };
struct mount *m;
char *discard;

blob_buf_init(&b, 0);
uci_to_blob(&b, s, &swap_attr_list);
Expand All @@ -321,11 +334,23 @@ static int swap_add(struct uci_section *s)
m->uuid = blobmsg_get_strdup(tb[SWAP_UUID]);
m->label = blobmsg_get_strdup(tb[SWAP_LABEL]);
m->device = blobmsg_get_basename(tb[SWAP_DEVICE]);
discard = blobmsg_get_strdup(tb[SWAP_DISCARD]);

if (tb[SWAP_PRIO])
m->prio = blobmsg_get_u32(tb[SWAP_PRIO]);
if (m->prio)
m->prio = ((m->prio << SWAP_FLAG_PRIO_SHIFT) & SWAP_FLAG_PRIO_MASK) | SWAP_FLAG_PREFER;

if (discard) {
if (!strcmp(discard, "yes") || !strcmp(discard, "1") || !strcmp(discard, "on"))
m->prio |= SWAP_FLAG_DISCARD;
else if (!strcmp(discard, "pages"))
m->prio |= (SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_PAGES);
else if (!strcmp(discard, "once"))
m->prio |= (SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE);
} else
m->prio |= SWAP_FLAG_DISCARD;

if ((!tb[SWAP_ENABLE]) || blobmsg_get_u32(tb[SWAP_ENABLE])) {
/* store complete swap path */
if (tb[SWAP_DEVICE])
Expand Down Expand Up @@ -1817,11 +1842,12 @@ static int main_info(int argc, char **argv)

static int swapon_usage(void)
{
fprintf(stderr, "Usage: swapon [-s] [-a] [[-p pri] DEVICE]\n\n"
"\tStart swapping on [DEVICE]\n"
" -a\tStart swapping on all swap devices\n"
" -p pri\tSet priority of swap device\n"
" -s\tShow summary\n");
fprintf(stderr, "Usage: swapon [-s] [-a] [ [[-p pri] [-d [once|pages]] DEVICE] ]\n\n"
"\t\t\tStart swapping on [DEVICE]\n"
" -a\t\t\tStart swapping on all swap devices\n"
" -p pri\t\t\tSet priority of swap device\n"
" -d [once|pages]\tEnable discard, using 'once', 'pages' or both (default) discard policy\n"
" -s\t\t\tShow summary\n");
return -1;
}

Expand All @@ -1837,12 +1863,11 @@ static int main_swapon(int argc, char **argv)
struct stat st;
int err;

while ((ch = getopt(argc, argv, "ap:s")) != -1) {
while ((ch = getopt(argc, argv, "ap:sd::")) != -1) {
switch(ch) {
case 's':
fp = fopen("/proc/swaps", "r");
lineptr = NULL;

if (!fp) {
ULOG_ERR("failed to open /proc/swaps\n");
return -1;
Expand All @@ -1858,14 +1883,34 @@ static int main_swapon(int argc, char **argv)
list_for_each_entry(pr, &devices, list) {
if (strcmp(pr->type, "swap"))
continue;
if (swapon(pr->dev, 0))
if (swapon(pr->dev, SWAP_FLAG_DISCARD))
ULOG_ERR("failed to swapon %s\n", pr->dev);
}
return 0;
case 'p':
pri = atoi(optarg);
if (pri >= 0)
flags = ((pri << SWAP_FLAG_PRIO_SHIFT) & SWAP_FLAG_PRIO_MASK) | SWAP_FLAG_PREFER;
flags |= ((pri << SWAP_FLAG_PRIO_SHIFT) & SWAP_FLAG_PRIO_MASK) | SWAP_FLAG_PREFER;
break;
case 'd':
lineptr = NULL;
flags |= SWAP_FLAG_DISCARD;
if (optarg)
lineptr = optarg;
else if (optind == (argc - 1))
break;
else if (optind < argc && argv[optind][0] != '-') {
lineptr = argv[optind];
optind++;
}
if (lineptr) {
if (!strcmp(lineptr, "once"))
flags |= SWAP_FLAG_DISCARD_ONCE;
else if (!strcmp(lineptr, "pages"))
flags |= SWAP_FLAG_DISCARD_PAGES;
else
return swapon_usage();
}
break;
default:
return swapon_usage();
Expand Down