lib: sbi_fifo: add TSA annotations

Add Thread Safety Analysis (TSA) annotations for the FIFO
implementation. This consists of indicating which fields are protected
by a spinlock and annotating functionst that must be called under a
spinlock. sbi_fifo_init() must be excluded, as acquiring a spinlock
before it is initialized does not make sense.

Signed-off-by: Carlos López <carlos.lopezr4096@gmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20260909162322.29778-5-carlos.lopezr4096@gmail.com
Signed-off-by: Anup Patel <anup@brainfault.org>

include/sbi/sbi_fifo.h

@@ -15,12 +15,12 @@
 #include <sbi/sbi_types.h>
 
 struct sbi_fifo {
-	void *queue;
 	spinlock_t qlock;
+	void *queue PT_GUARDED_BY(&qlock);
 	u16 entry_size;
 	u16 num_entries;
-	u16 avail;
-	u16 tail;
+	u16 avail GUARDED_BY(&qlock);
+	u16 tail GUARDED_BY(&qlock);
 };
 
 #define SBI_FIFO_INITIALIZER(__queue_mem, __entries, __entry_size)	\

lib/sbi/sbi_fifo.c

@@ -13,7 +13,7 @@
 #include <sbi/sbi_string.h>
 
 void sbi_fifo_init(struct sbi_fifo *fifo, void *queue_mem, u16 entries,
-		   u16 entry_size)
+		   u16 entry_size) NO_THREAD_SAFETY_ANALYSIS
 {
 	fifo->queue	  = queue_mem;
 	fifo->num_entries = entries;
@@ -25,6 +25,7 @@ void sbi_fifo_init(struct sbi_fifo *fifo, void *queue_mem, u16 entries,
 
 /* Note: must be called with fifo->qlock held */
 static inline bool __sbi_fifo_is_full(struct sbi_fifo *fifo)
+	MUST_HOLD(&fifo->qlock)
 {
 	return (fifo->avail == fifo->num_entries) ? true : false;
 }
@@ -59,6 +60,7 @@ int sbi_fifo_is_full(struct sbi_fifo *fifo)
 
 /* Note: must be called with fifo->qlock held */
 static inline void __sbi_fifo_enqueue(struct sbi_fifo *fifo, void *data)
+	MUST_HOLD(&fifo->qlock)
 {
 	u32 head;
 
@@ -92,6 +94,7 @@ static inline void  __sbi_fifo_enqueue(struct sbi_fifo *fifo, void *data)
 
 /* Note: must be called with fifo->qlock held */
 static inline void __sbi_fifo_dequeue(struct sbi_fifo *fifo, void *data)
+	MUST_HOLD(&fifo->qlock)
 {
 	if (!data)
 		goto skip_data_copy;
@@ -126,6 +129,7 @@ skip_data_copy:
 
 /* Note: must be called with fifo->qlock held */
 static inline bool __sbi_fifo_is_empty(struct sbi_fifo *fifo)
+	MUST_HOLD(&fifo->qlock)
 {
 	return (fifo->avail == 0) ? true : false;
 }
@@ -146,6 +150,7 @@ int sbi_fifo_is_empty(struct sbi_fifo *fifo)
 
 /* Note: must be called with fifo->qlock held */
 static inline void __sbi_fifo_reset(struct sbi_fifo *fifo)
+	MUST_HOLD(&fifo->qlock)
 {
 	size_t size = (size_t)fifo->num_entries * fifo->entry_size;