[PATCH 1/2] s390/dasd: Add __context_unsafe() attribute to various functions

[Heiko Carstens <hca@linux.ibm.com>]

Disable context analysis for various functions to get rid of context
analysis compile time warnings using clang caused by conditional
locking like e.g.:

drivers/s390/block/dasd_eckd.c:1462:3:
  warning: releasing mutex 'dasd_pe_handler_mutex' that was not held [-Wthread-safety-analysis]
 1462 |                 mutex_unlock(&dasd_pe_handler_mutex);
      |                 ^

Use __context_unsafe() to provide a short comment why context analysis is
disabled for each function. It doesn't look like those functions can be
easily reworked to get rid of conditional locking.
Therefore disable context analysis for (only) those functions.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
---
 drivers/s390/block/dasd_eckd.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index bacf770c0e1f..b4dcef06edaa 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -1468,6 +1468,7 @@ static void dasd_eckd_path_available_action(struct dasd_device *device,
 }
 
 static void do_pe_handler_work(struct work_struct *work)
+__context_unsafe(/* Conditional locking */)
 {
 	struct pe_handler_work_data *data;
 	struct dasd_device *device;
@@ -1501,6 +1502,7 @@ static void do_pe_handler_work(struct work_struct *work)
 
 static int dasd_eckd_pe_handler(struct dasd_device *device,
 				__u8 tbvpm, __u8 fcsecpm)
+__context_unsafe(/* Conditional locking */)
 {
 	struct pe_handler_work_data *data;
 
@@ -1601,6 +1603,7 @@ static int dasd_eckd_read_features(struct dasd_device *device)
 
 /* Read Volume Information - Volume Storage Query */
 static int dasd_eckd_read_vol_info(struct dasd_device *device)
+__context_unsafe(/* Conditional locking */)
 {
 	struct dasd_eckd_private *private = device->private;
 	struct dasd_psf_prssd_data *prssdp;
@@ -5965,6 +5968,7 @@ dasd_eckd_fill_info(struct dasd_device * device,
  */
 static int
 dasd_eckd_release(struct dasd_device *device)
+__context_unsafe(/* Conditional locking */)
 {
 	struct dasd_ccw_req *cqr;
 	int rc;
@@ -6020,6 +6024,7 @@ dasd_eckd_release(struct dasd_device *device)
  */
 static int
 dasd_eckd_reserve(struct dasd_device *device)
+__context_unsafe(/* Conditional locking */)
 {
 	struct dasd_ccw_req *cqr;
 	int rc;
@@ -6074,6 +6079,7 @@ dasd_eckd_reserve(struct dasd_device *device)
  */
 static int
 dasd_eckd_steal_lock(struct dasd_device *device)
+__context_unsafe(/* Conditional locking */)
 {
 	struct dasd_ccw_req *cqr;
 	int rc;
@@ -6129,6 +6135,7 @@ dasd_eckd_steal_lock(struct dasd_device *device)
  */
 static int dasd_eckd_snid(struct dasd_device *device,
 			  void __user *argp)
+__context_unsafe(/* Conditional locking */)
 {
 	struct dasd_ccw_req *cqr;
 	int rc;
-- 
2.53.0