From 748e4f3d702def1a4bff191e0cf93b6a05340f01 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Fri, 10 May 2024 07:41:34 +0000
Subject: [PATCH] add gpio led uart
---
kernel/include/linux/mbcache.h | 41 +++++++++++++++++++++++++++++++----------
1 files changed, 31 insertions(+), 10 deletions(-)
diff --git a/kernel/include/linux/mbcache.h b/kernel/include/linux/mbcache.h
index 20f1e3f..591bc4c 100644
--- a/kernel/include/linux/mbcache.h
+++ b/kernel/include/linux/mbcache.h
@@ -10,16 +10,29 @@
struct mb_cache;
+/* Cache entry flags */
+enum {
+ MBE_REFERENCED_B = 0,
+ MBE_REUSABLE_B
+};
+
struct mb_cache_entry {
/* List of entries in cache - protected by cache->c_list_lock */
struct list_head e_list;
- /* Hash table list - protected by hash chain bitlock */
+ /*
+ * Hash table list - protected by hash chain bitlock. The entry is
+ * guaranteed to be hashed while e_refcnt > 0.
+ */
struct hlist_bl_node e_hash_list;
+ /*
+ * Entry refcount. Once it reaches zero, entry is unhashed and freed.
+ * While refcount > 0, the entry is guaranteed to stay in the hash and
+ * e.g. mb_cache_entry_try_delete() will fail.
+ */
atomic_t e_refcnt;
/* Key in hash - stable during lifetime of the entry */
u32 e_key;
- u32 e_referenced:1;
- u32 e_reusable:1;
+ unsigned long e_flags;
/* User provided value - stable during lifetime of the entry */
u64 e_value;
};
@@ -29,16 +42,24 @@
int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key,
u64 value, bool reusable);
-void __mb_cache_entry_free(struct mb_cache_entry *entry);
-static inline int mb_cache_entry_put(struct mb_cache *cache,
- struct mb_cache_entry *entry)
+void __mb_cache_entry_free(struct mb_cache *cache,
+ struct mb_cache_entry *entry);
+void mb_cache_entry_wait_unused(struct mb_cache_entry *entry);
+static inline void mb_cache_entry_put(struct mb_cache *cache,
+ struct mb_cache_entry *entry)
{
- if (!atomic_dec_and_test(&entry->e_refcnt))
- return 0;
- __mb_cache_entry_free(entry);
- return 1;
+ unsigned int cnt = atomic_dec_return(&entry->e_refcnt);
+
+ if (cnt > 0) {
+ if (cnt <= 2)
+ wake_up_var(&entry->e_refcnt);
+ return;
+ }
+ __mb_cache_entry_free(cache, entry);
}
+struct mb_cache_entry *mb_cache_entry_delete_or_get(struct mb_cache *cache,
+ u32 key, u64 value);
void mb_cache_entry_delete(struct mb_cache *cache, u32 key, u64 value);
struct mb_cache_entry *mb_cache_entry_get(struct mb_cache *cache, u32 key,
u64 value);
--
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