[PATCH v2 24/26] zram: Enable lock context analysis

[Bart Van Assche <bvanassche@acm.org>]

Add the lock context annotations that are required by Clang. Enable lock
context analysis in the Makefile.

Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/block/zram/Makefile   | 2 ++
 drivers/block/zram/zcomp.c    | 3 ++-
 drivers/block/zram/zcomp.h    | 6 ++++--
 drivers/block/zram/zram_drv.c | 1 +
 4 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/block/zram/Makefile b/drivers/block/zram/Makefile
index 0fdefd576691..a5663ab01653 100644
--- a/drivers/block/zram/Makefile
+++ b/drivers/block/zram/Makefile
@@ -1,5 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
+CONTEXT_ANALYSIS := y
+
 zram-y	:=	zcomp.o zram_drv.o
 
 zram-$(CONFIG_ZRAM_BACKEND_LZO)		+= backend_lzorle.o backend_lzo.o
diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index a771a8ecc540..5f431596f3b5 100644
--- a/drivers/block/zram/zcomp.c
+++ b/drivers/block/zram/zcomp.c
@@ -107,7 +107,8 @@ ssize_t zcomp_available_show(const char *comp, char *buf, ssize_t at)
 	return at;
 }
 
-struct zcomp_strm *zcomp_stream_get(struct zcomp *comp)
+struct zcomp_strm *__zcomp_stream_get(struct zcomp *comp)
+	__no_context_analysis /* __acquires(&raw_cpu_ptr(comp->stream)->lock) */
 {
 	for (;;) {
 		struct zcomp_strm *zstrm = raw_cpu_ptr(comp->stream);
diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h
index eacfd3f7d61d..4814087e8ac9 100644
--- a/drivers/block/zram/zcomp.h
+++ b/drivers/block/zram/zcomp.h
@@ -85,8 +85,10 @@ bool zcomp_available_algorithm(const char *comp);
 struct zcomp *zcomp_create(const char *alg, struct zcomp_params *params);
 void zcomp_destroy(struct zcomp *comp);
 
-struct zcomp_strm *zcomp_stream_get(struct zcomp *comp);
-void zcomp_stream_put(struct zcomp_strm *zstrm);
+#define zcomp_stream_get(...) __acquire_ret(__zcomp_stream_get(__VA_ARGS__), &__ret->lock)
+struct zcomp_strm *__zcomp_stream_get(struct zcomp *comp);
+void zcomp_stream_put(struct zcomp_strm *zstrm)
+	__releases(&zstrm->lock);
 
 int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm,
 		   const void *src, unsigned int *dst_len);
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index a324ede6206d..e0f716d80369 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -2395,6 +2395,7 @@ static int scan_slots_for_recompress(struct zram *zram, u32 mode, u32 prio_max,
 static int recompress_slot(struct zram *zram, u32 index, struct page *page,
 			   u64 *num_recomp_pages, u32 threshold, u32 prio,
 			   u32 prio_max)
+	__no_context_analysis /* too complex for Clang */
 {
 	struct zcomp_strm *zstrm = NULL;
 	unsigned long handle_old;