diff mbox series

[3/3] Bluetooth: Limit duration of Remote Name Resolve

Message ID 20211111195320.3.I35b7f3a496f834de6b43a32f94b6160cb1467c94@changeid (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series [1/3] Bluetooth: Send device found event on name resolve failure | expand

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Context Check Description
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix warning Target tree name not specified in the subject
netdev/cover_letter warning Series does not have a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 36 this patch: 36
netdev/cc_maintainers success CCed 7 of 7 maintainers
netdev/build_clang success Errors and warnings before: 4 this patch: 4
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 36 this patch: 36
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 34 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/tree_selection success Guessing tree name failed - patch did not apply

Commit Message

Archie Pusaka Nov. 11, 2021, 11:53 a.m. UTC 
From: Archie Pusaka <apusaka@chromium.org>

When doing remote name request, we cannot scan. In the normal case it's
OK since we can expect it to finish within a short amount of time.
However, there is a possibility to scan lots of devices that
(1) requires Remote Name Resolve
(2) is unresponsive to Remote Name Resolve
When this happens, we are stuck to do Remote Name Resolve until all is
done before continue scanning.

This patch adds a time limit to stop us spending too long on remote
name request.

Signed-off-by: Archie Pusaka <apusaka@chromium.org>
Reviewed-by: Miao-chen Chou <mcchou@chromium.org>
---

 include/net/bluetooth/hci_core.h | 3 +++
 net/bluetooth/hci_event.c        | 7 +++++++
 2 files changed, 10 insertions(+)
diff mbox series

Patch

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index eb08dd502f2a..941cfbb024d1 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -89,6 +89,7 @@  struct discovery_state {
 	u8			(*uuids)[16];
 	unsigned long		scan_start;
 	unsigned long		scan_duration;
+	unsigned long		name_resolve_timeout;
 };
 
 #define SUSPEND_NOTIFIER_TIMEOUT	msecs_to_jiffies(2000) /* 2 seconds */
@@ -1763,6 +1764,8 @@  void hci_mgmt_chan_unregister(struct hci_mgmt_chan *c);
 #define DISCOV_LE_FAST_ADV_INT_MIN	0x00A0	/* 100 msec */
 #define DISCOV_LE_FAST_ADV_INT_MAX	0x00F0	/* 150 msec */
 
+#define NAME_RESOLVE_DURATION		msecs_to_jiffies(10240)	/* msec */
+
 void mgmt_fill_version_info(void *ver);
 int mgmt_new_settings(struct hci_dev *hdev);
 void mgmt_index_added(struct hci_dev *hdev);
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 2de3080659f9..6180ab0e8b8d 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -2129,6 +2129,12 @@  static bool hci_resolve_next_name(struct hci_dev *hdev)
 	if (list_empty(&discov->resolve))
 		return false;
 
+	/* We should stop if we already spent too much time resolving names. */
+	if (time_after(jiffies, discov->name_resolve_timeout)) {
+		bt_dev_dbg(hdev, "Name resolve takes too long, stopping.");
+		return false;
+	}
+
 	e = hci_inquiry_cache_lookup_resolve(hdev, BDADDR_ANY, NAME_NEEDED);
 	if (!e)
 		return false;
@@ -2716,6 +2722,7 @@  static void hci_inquiry_complete_evt(struct hci_dev *hdev, struct sk_buff *skb)
 	if (e && hci_resolve_name(hdev, e) == 0) {
 		e->name_state = NAME_PENDING;
 		hci_discovery_set_state(hdev, DISCOVERY_RESOLVING);
+		discov->name_resolve_timeout = jiffies + NAME_RESOLVE_DURATION;
 	} else {
 		/* When BR/EDR inquiry is active and no LE scanning is in
 		 * progress, then change discovery state to indicate completion.