[PATCH] firmware: arm_scmi: Support loop control in quirk code snippets

[Geert Uytterhoeven]

Each SCMI firmware quirk contains a code snippet, which handles the
quirk, and has full access to the surrounding context.  When this
context is (part of) a loop body, the code snippet may want to use loop
control statements like "break" and "continue".  Unfortunately the
SCMI_QUIRK() macro implementation contains a dummy loop, taking
precedence over any outer loops.  Hence quirk code cannot use loop
control statements, but has to resort to polluting the surrounding
context with a label, and use goto.

Fix this by replacing the "do { ... } while (0)" construct in the
SCMI_QUIRK() implementation by "({ ... })".

Signed-off-by: Geert Uytterhoeven <geert+renesas at glider.be>
---
Example:

    #define QUIRK_EXAMPLE					\
	    ({							\
		    if (ret == -EOPNOTSUPP)			\
			    continue;				\
	    })

    for (unsigned int i = 0; i < n; i++) {
	    ret = foo(handle, i);
	    SCMI_QUIRK(example_quirk, QUIRK_EXAMPLE);
	    if (ret)
		    return ret;

	    ret = bar(handle, i);
	    if (ret)
		    return ret;
    }
---
 drivers/firmware/arm_scmi/quirks.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/firmware/arm_scmi/quirks.h b/drivers/firmware/arm_scmi/quirks.h
index a71fde85a5272aff..d8ba60b956522d04 100644
--- a/drivers/firmware/arm_scmi/quirks.h
+++ b/drivers/firmware/arm_scmi/quirks.h
@@ -20,10 +20,10 @@
  * named as _qn.
  */
 #define SCMI_QUIRK(_qn, _blk)						\
-	do {								\
+	({								\
 		if (static_branch_unlikely(&(scmi_quirk_ ## _qn)))	\
 			(_blk);						\
-	} while (0)
+	})
 
 void scmi_quirks_initialize(void);
 void scmi_quirks_enable(struct device *dev, const char *vend,
@@ -34,10 +34,10 @@ void scmi_quirks_enable(struct device *dev, const char *vend,
 #define DECLARE_SCMI_QUIRK(_qn)
 /* Force quirks compilation even when SCMI Quirks are disabled */
 #define SCMI_QUIRK(_qn, _blk)						\
-	do {								\
+	({								\
 		if (0)							\
 			(_blk);						\
-	} while (0)
+	})
 
 static inline void scmi_quirks_initialize(void) { }
 static inline void scmi_quirks_enable(struct device *dev, const char *vend,
-- 
2.43.0