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device_get_path(): take sbuf directly

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This allows to fix a bug where sbuf allocation done in the context of
dev_wired_cache_match() must use non-sleepable allocations.

Suggested by:	jhb
Reviewed by:	jhb, takawata
Discussed with:	imp
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D36899
This commit is contained in:
Konstantin Belousov 2022-10-08 03:08:14 +03:00
parent 8cf783bde3
commit 555a861d68
1 changed files with 35 additions and 38 deletions
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73
sys/kern/subr_bus.c
View File

@ -5305,37 +5305,24 @@ device_do_deferred_actions(void)
}
static int
device_get_path(device_t dev, const char *locator, char **rvp)
device_get_path(device_t dev, const char *locator, struct sbuf *sb)
{
struct sbuf *sb;
char *s;
device_t parent;
ssize_t len;
int error;
sb = sbuf_new(NULL, NULL, 0, SBUF_AUTOEXTEND | SBUF_INCLUDENUL);
parent = device_get_parent(dev);
if (parent == NULL) {
*rvp = strdup_flags("/", M_BUS, M_NOWAIT);
return (*rvp == NULL ? ENOMEM : 0);
}
sb = sbuf_new(NULL, NULL, 0, SBUF_AUTOEXTEND | SBUF_INCLUDENUL);
error = BUS_GET_DEVICE_PATH(parent, dev, locator, sb);
sbuf_finish(sb); /* Note: errors checked with sbuf_len() below */
if (error == 0) {
len = sbuf_len(sb);
if (len <= 1) {
error = EIO;
} else {
s = malloc(len, M_BUS, M_NOWAIT);
if (s == NULL) {
error = ENOMEM;
} else {
memcpy(s, sbuf_data(sb), len);
*rvp = s;
}
error = sbuf_printf(sb, "/");
} else {
error = BUS_GET_DEVICE_PATH(parent, dev, locator, sb);
if (error == 0) {
error = sbuf_error(sb);
if (error == 0 && sbuf_len(sb) <= 1)
error = EIO;
}
}
sbuf_delete(sb);
sbuf_finish(sb);
return (error);
}
@ -5599,25 +5586,28 @@ devctl2_ioctl(struct cdev *cdev, u_long cmd, caddr_t data, int fflag,
req->dr_flags);
break;
case DEV_GET_PATH: {
struct sbuf *sb;
char locator[64];
char *path;
ssize_t len;
error = copyinstr(req->dr_buffer.buffer, locator,
sizeof(locator), NULL);
if (error != 0)
break;
error = device_get_path(dev, locator, &path);
if (error != 0)
break;
len = strlen(path) + 1;
if (req->dr_buffer.length < len) {
error = ENAMETOOLONG;
} else {
error = copyout(path, req->dr_buffer.buffer, len);
sb = sbuf_new(NULL, NULL, 0, SBUF_AUTOEXTEND |
SBUF_INCLUDENUL /* | SBUF_WAITOK */);
error = device_get_path(dev, locator, sb);
if (error == 0) {
len = sbuf_len(sb);
if (req->dr_buffer.length < len) {
error = ENAMETOOLONG;
} else {
error = copyout(sbuf_data(sb),
req->dr_buffer.buffer, len);
}
req->dr_buffer.length = len;
}
req->dr_buffer.length = len;
free(path, M_BUS);
sbuf_delete(sb);
break;
}
}
@ -5712,8 +5702,8 @@ bool
dev_wired_cache_match(device_location_cache_t *dcp, device_t dev,
const char *at)
{
struct sbuf *sb;
const char *cp;
char *path;
char locator[32];
int error, len;
struct device_location_node *res;
@ -5732,9 +5722,16 @@ dev_wired_cache_match(device_location_cache_t *dcp, device_t dev,
/* maybe cache this inside device_t and look that up, but not yet */
res = dev_wired_cache_lookup(dcp, locator);
if (res == NULL) {
error = device_get_path(dev, locator, &path);
if (error == 0)
res = dev_wired_cache_add(dcp, locator, path);
sb = sbuf_new(NULL, NULL, 0, SBUF_AUTOEXTEND |
SBUF_INCLUDENUL | SBUF_NOWAIT);
if (sb != NULL) {
error = device_get_path(dev, locator, sb);
if (error == 0) {
res = dev_wired_cache_add(dcp, locator,
sbuf_data(sb));
}
sbuf_delete(sb);
}
}
if (error != 0 || res == NULL || res->dln_path == NULL)
return (false);