[PATCH v3 56/57] scsi: core: Enable lock context analysis

Document which functions expect that shost->scan_mutex is held. Inform
the compiler about synchronization object aliases with __assume_ctx_lock().
Enable lock context analysis for the SCSI core and also for all drivers
in the drivers/scsi/ directory.

Signed-off-by: Bart Van Assche <[email protected]>
---
 drivers/scsi/Makefile                | 1 +
 drivers/scsi/device_handler/Makefile | 3 +++
 drivers/scsi/scsi_scan.c             | 5 +++++
 include/scsi/scsi_host.h             | 2 ++
 4 files changed, 11 insertions(+)

diff --git a/drivers/scsi/Makefile b/drivers/scsi/Makefile
index 842c254bb226..a1fbdf4b0705 100644
--- a/drivers/scsi/Makefile
+++ b/drivers/scsi/Makefile
@@ -14,6 +14,7 @@
 # satisfy certain initialization assumptions in the SCSI layer.
 # *!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!*!
 
+CONTEXT_ANALYSIS := y
 
 CFLAGS_aha152x.o =   -DAHA152X_STAT -DAUTOCONF
 
diff --git a/drivers/scsi/device_handler/Makefile b/drivers/scsi/device_handler/Makefile
index 0a603aefd2bb..5aa282a63e24 100644
--- a/drivers/scsi/device_handler/Makefile
+++ b/drivers/scsi/device_handler/Makefile
@@ -2,6 +2,9 @@
 #
 # SCSI Device Handler
 #
+
+CONTEXT_ANALYSIS := y
+
 obj-$(CONFIG_SCSI_DH_RDAC)	+= scsi_dh_rdac.o
 obj-$(CONFIG_SCSI_DH_HP_SW)	+= scsi_dh_hp_sw.o
 obj-$(CONFIG_SCSI_DH_EMC)	+= scsi_dh_emc.o
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index a8994c07d415..8096ca51161b 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -1195,6 +1195,7 @@ static int scsi_probe_and_add_lun(struct Scsi_Host *shost,
 				  struct scsi_device **sdevp,
 				  enum scsi_scan_mode rescan,
 				  void *hostdata)
+	__must_hold(&shost->scan_mutex)
 {
 	struct scsi_device *sdev;
 	unsigned char *result;
@@ -1352,6 +1353,7 @@ static void scsi_sequential_lun_scan(struct Scsi_Host *shost,
 				     struct scsi_target *starget,
 				     blist_flags_t bflags, int scsi_level,
 				     enum scsi_scan_mode rescan)
+	__must_hold(&shost->scan_mutex)
 {
 	uint max_dev_lun;
 	u64 sparse_lun, lun;
@@ -1443,6 +1445,7 @@ static void scsi_sequential_lun_scan(struct Scsi_Host *shost,
 static int scsi_report_lun_scan(struct Scsi_Host *shost,
 			struct scsi_target *starget, blist_flags_t bflags,
 			enum scsi_scan_mode rescan)
+	__must_hold(&shost->scan_mutex)
 {
 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
 	unsigned int length;
@@ -1768,6 +1771,7 @@ EXPORT_SYMBOL(scsi_rescan_device);
 static void __scsi_scan_target(struct Scsi_Host *shost, struct device *parent,
 			       unsigned int channel, unsigned int id, u64 lun,
 			       enum scsi_scan_mode rescan)
+	__must_hold(&shost->scan_mutex)
 {
 	blist_flags_t bflags = 0;
 	int res;
@@ -1865,6 +1869,7 @@ EXPORT_SYMBOL(scsi_scan_target);
 static void scsi_scan_channel(struct Scsi_Host *shost, unsigned int channel,
 			      unsigned int id, u64 lun,
 			      enum scsi_scan_mode rescan)
+	__must_hold(&shost->scan_mutex)
 {
 	uint order_id;
 
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 7e2011830ba4..2bbe7cb0060b 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -534,6 +534,8 @@ struct scsi_host_template {
 		enum scsi_qc_status rc;					\
 									\
 		spin_lock_irqsave(shost->host_lock, irq_flags);		\
+		/* Tell the compiler that cmd->device->host == shost. */\
+		__assume_ctx_lock(cmd->device->host->host_lock);	\
 		rc = func_name##_lck(cmd);				\
 		spin_unlock_irqrestore(shost->host_lock, irq_flags);	\
 		return rc;						\