IB/qib: Use device_show_string() helper for sysfs attributes

Deduplicate sysfs ->show() callbacks which expose a string at a static
memory location.  Use the newly introduced device_show_string() helper
in the driver core instead by declaring those sysfs attributes with
DEVICE_STRING_ATTR_RO().

No functional change intended.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/185a88dd3e6e18bf508a875d87c95ea2a5c3fa13.1713608122.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: l1k

drivers/infiniband/hw/qib/qib.h

@@ -1359,7 +1359,6 @@ static inline u32 qib_get_rcvhdrtail(const struct qib_ctxtdata *rcd)
  * sysfs interface.
  */
 
-extern const char ib_qib_version[];
 extern const struct attribute_group qib_attr_group;
 extern const struct attribute_group *qib_attr_port_groups[];
 

drivers/infiniband/hw/qib/qib_driver.c

@@ -44,12 +44,6 @@
 
 #include "qib.h"
 
-/*
- * The size has to be longer than this string, so we can append
- * board/chip information to it in the init code.
- */
-const char ib_qib_version[] = QIB_DRIVER_VERSION "\n";
-
 DEFINE_MUTEX(qib_mutex);	/* general driver use */
 
 unsigned qib_ibmtu;

drivers/infiniband/hw/qib/qib_sysfs.c

@@ -585,13 +585,7 @@ static ssize_t hca_type_show(struct device *device,
 static DEVICE_ATTR_RO(hca_type);
 static DEVICE_ATTR(board_id, 0444, hca_type_show, NULL);
 
-static ssize_t version_show(struct device *device,
-			    struct device_attribute *attr, char *buf)
-{
-	/* The string printed here is already newline-terminated. */
-	return sysfs_emit(buf, "%s", (char *)ib_qib_version);
-}
-static DEVICE_ATTR_RO(version);
+static DEVICE_STRING_ATTR_RO(version, 0444, QIB_DRIVER_VERSION);
 
 static ssize_t boardversion_show(struct device *device,
 				 struct device_attribute *attr, char *buf)
@@ -721,7 +715,7 @@ static struct attribute *qib_attributes[] = {
 	&dev_attr_hw_rev.attr,
 	&dev_attr_hca_type.attr,
 	&dev_attr_board_id.attr,
-	&dev_attr_version.attr,
+	&dev_attr_version.attr.attr,
 	&dev_attr_nctxts.attr,
 	&dev_attr_nfreectxts.attr,
 	&dev_attr_serial.attr,