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From: Arnd Bergmann <arnd@kernel.org>
To: "James E.J. Bottomley" <jejb@linux.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Bill Wendling <morbo@google.com>,
	Justin Stitt <justinstitt@google.com>,
	James Bottomley <JBottomley@Parallels.com>,
	Naresh Kumar Inna <naresh@chelsio.com>,
	linux-scsi@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	llvm@lists.linux.dev
Subject: [PATCH] scsi: csiostor: avoid function pointer casts
Date: Tue, 13 Feb 2024 11:05:00 +0100
Message-Id: <20240213100518.457623-1-arnd@kernel.org>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

From: Arnd Bergmann <arnd@arndb.de>

csiostor uses function pointer casts to keep the csio_ln_ev state machine
hidden, but this causes warnings about control flow integrity (KCFI) violations
in clang-16 and higher:

drivers/scsi/csiostor/csio_lnode.c:1098:33: error: cast from 'void (*)(struct csio_lnode *, enum csio_ln_ev)' to 'csio_sm_state_t' (aka 'void (*)(void *, unsigned int)') converts to incompatible function type [-Werror,-Wcast-function-type-strict]
 1098 |         return (csio_get_state(ln) == ((csio_sm_state_t)csio_lns_ready));
      |                                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/csiostor/csio_lnode.c:1369:29: error: cast from 'void (*)(struct csio_lnode *, enum csio_ln_ev)' to 'csio_sm_state_t' (aka 'void (*)(void *, unsigned int)') converts to incompatible function type [-Werror,-Wcast-function-type-strict]
 1369 |         if (csio_get_state(ln) == ((csio_sm_state_t)csio_lns_uninit)) {
      |                                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/csiostor/csio_lnode.c:1373:29: error: cast from 'void (*)(struct csio_lnode *, enum csio_ln_ev)' to 'csio_sm_state_t' (aka 'void (*)(void *, unsigned int)') converts to incompatible function type [-Werror,-Wcast-function-type-strict]
 1373 |         if (csio_get_state(ln) == ((csio_sm_state_t)csio_lns_ready)) {
      |                                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/scsi/csiostor/csio_lnode.c:1377:29: error: cast from 'void (*)(struct csio_lnode *, enum csio_ln_ev)' to 'csio_sm_state_t' (aka 'void (*)(void *, unsigned int)') converts to incompatible function type [-Werror,-Wcast-function-type-strict]
 1377 |         if (csio_get_state(ln) == ((csio_sm_state_t)csio_lns_offline)) {
      |                                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Move the enum into a shared header so the correct types can be used without the
need for casts.

Fixes: a3667aaed569 ("[SCSI] csiostor: Chelsio FCoE offload driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/scsi/csiostor/csio_defs.h  | 18 ++++++++++++++++--
 drivers/scsi/csiostor/csio_lnode.c |  8 ++++----
 drivers/scsi/csiostor/csio_lnode.h | 13 -------------
 3 files changed, 20 insertions(+), 19 deletions(-)

diff --git a/drivers/scsi/csiostor/csio_defs.h b/drivers/scsi/csiostor/csio_defs.h
index c38017b4af98..e50e93e7fe5a 100644
--- a/drivers/scsi/csiostor/csio_defs.h
+++ b/drivers/scsi/csiostor/csio_defs.h
@@ -73,7 +73,21 @@ csio_list_deleted(struct list_head *list)
 #define csio_list_prev(elem)	(((struct list_head *)(elem))->prev)
 
 /* State machine */
-typedef void (*csio_sm_state_t)(void *, uint32_t);
+struct csio_lnode;
+
+/* State machine evets */
+enum csio_ln_ev {
+	CSIO_LNE_NONE = (uint32_t)0,
+	CSIO_LNE_LINKUP,
+	CSIO_LNE_FAB_INIT_DONE,
+	CSIO_LNE_LINK_DOWN,
+	CSIO_LNE_DOWN_LINK,
+	CSIO_LNE_LOGO,
+	CSIO_LNE_CLOSE,
+	CSIO_LNE_MAX_EVENT,
+};
+
+typedef void (*csio_sm_state_t)(struct csio_lnode *ln, enum csio_ln_ev evt);
 
 struct csio_sm {
 	struct list_head	sm_list;
@@ -83,7 +97,7 @@ struct csio_sm {
 static inline void
 csio_set_state(void *smp, void *state)
 {
-	((struct csio_sm *)smp)->sm_state = (csio_sm_state_t)state;
+	((struct csio_sm *)smp)->sm_state = state;
 }
 
 static inline void
diff --git a/drivers/scsi/csiostor/csio_lnode.c b/drivers/scsi/csiostor/csio_lnode.c
index d5ac93897023..5b3ffefae476 100644
--- a/drivers/scsi/csiostor/csio_lnode.c
+++ b/drivers/scsi/csiostor/csio_lnode.c
@@ -1095,7 +1095,7 @@ csio_handle_link_down(struct csio_hw *hw, uint8_t portid, uint32_t fcfi,
 int
 csio_is_lnode_ready(struct csio_lnode *ln)
 {
-	return (csio_get_state(ln) == ((csio_sm_state_t)csio_lns_ready));
+	return (csio_get_state(ln) == csio_lns_ready);
 }
 
 /*****************************************************************************/
@@ -1366,15 +1366,15 @@ csio_free_fcfinfo(struct kref *kref)
 void
 csio_lnode_state_to_str(struct csio_lnode *ln, int8_t *str)
 {
-	if (csio_get_state(ln) == ((csio_sm_state_t)csio_lns_uninit)) {
+	if (csio_get_state(ln) == csio_lns_uninit) {
 		strcpy(str, "UNINIT");
 		return;
 	}
-	if (csio_get_state(ln) == ((csio_sm_state_t)csio_lns_ready)) {
+	if (csio_get_state(ln) == csio_lns_ready) {
 		strcpy(str, "READY");
 		return;
 	}
-	if (csio_get_state(ln) == ((csio_sm_state_t)csio_lns_offline)) {
+	if (csio_get_state(ln) == csio_lns_offline) {
 		strcpy(str, "OFFLINE");
 		return;
 	}
diff --git a/drivers/scsi/csiostor/csio_lnode.h b/drivers/scsi/csiostor/csio_lnode.h
index 372a67d122d3..607698a0f063 100644
--- a/drivers/scsi/csiostor/csio_lnode.h
+++ b/drivers/scsi/csiostor/csio_lnode.h
@@ -53,19 +53,6 @@
 extern int csio_fcoe_rnodes;
 extern int csio_fdmi_enable;
 
-/* State machine evets */
-enum csio_ln_ev {
-	CSIO_LNE_NONE = (uint32_t)0,
-	CSIO_LNE_LINKUP,
-	CSIO_LNE_FAB_INIT_DONE,
-	CSIO_LNE_LINK_DOWN,
-	CSIO_LNE_DOWN_LINK,
-	CSIO_LNE_LOGO,
-	CSIO_LNE_CLOSE,
-	CSIO_LNE_MAX_EVENT,
-};
-
-
 struct csio_fcf_info {
 	struct list_head	list;
 	uint8_t			priority;
-- 
2.39.2