diff mbox series

[net-next,v3,3/4] netconsole: Attach cmdline target to dynamic target

Message ID 20231010093751.3878229-4-leitao@debian.org (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series net: netconsole: configfs entries for boot target | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1361 this patch: 1361
netdev/cc_maintainers success CCed 5 of 5 maintainers
netdev/build_clang success Errors and warnings before: 1386 this patch: 1386
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1386 this patch: 1386
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 40 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Breno Leitao Oct. 10, 2023, 9:37 a.m. UTC
Enable the attachment of a dynamic target to the target created during
boot time. The boot-time targets are named as "cmdline\d", where "\d" is
a number starting at 0.

If the user creates a dynamic target named "cmdline0", it will attach to
the first target created at boot time (as defined in the
`netconsole=...` command line argument). `cmdline1` will attach to the
second target and so forth.

If there is no netconsole target created at boot time, then, the target
name could be reused.

Relevant design discussion:
https://lore.kernel.org/all/ZRWRal5bW93px4km@gmail.com/

Suggested-by: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
---
 drivers/net/netconsole.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)
diff mbox series

Patch

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 3d7002af505d..519f4d065921 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -629,6 +629,23 @@  static const struct config_item_type netconsole_target_type = {
 	.ct_owner		= THIS_MODULE,
 };
 
+static struct netconsole_target *find_cmdline_target(const char *name)
+{
+	struct netconsole_target *nt, *ret = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&target_list_lock, flags);
+	list_for_each_entry(nt, &target_list, list) {
+		if (!strcmp(nt->item.ci_name, name)) {
+			ret = nt;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&target_list_lock, flags);
+
+	return ret;
+}
+
 /*
  * Group operations and type for netconsole_subsys.
  */
@@ -639,6 +656,17 @@  static struct config_item *make_netconsole_target(struct config_group *group,
 	struct netconsole_target *nt;
 	unsigned long flags;
 
+	/* Checking if a target by this name was created at boot time.  If so,
+	 * attach a configfs entry to that target.  This enables dynamic
+	 * control.
+	 */
+	if (!strncmp(name, NETCONSOLE_PARAM_TARGET_NAME,
+		     strlen(NETCONSOLE_PARAM_TARGET_NAME))) {
+		nt = find_cmdline_target(name);
+		if (nt)
+			return &nt->item;
+	}
+
 	nt = alloc_and_init();
 	if (!nt)
 		return ERR_PTR(-ENOMEM);