iommu: Use sysfs_emit() for sysfs show

Use sysfs_emit() instead of the sprintf() for sysfs entries. sysfs_emit()
knows the maximum of the temporary buffer used for outputting sysfs
content and avoids overrunning the buffer length.

Prefer 'long long' over 'long long int' as suggested by checkpatch.pl.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20230322123421.278852-1-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: LuBaolu

drivers/iommu/amd/init.c

@@ -1941,7 +1941,7 @@ static ssize_t amd_iommu_show_cap(struct device *dev,
 				  char *buf)
 {
 	struct amd_iommu *iommu = dev_to_amd_iommu(dev);
-	return sprintf(buf, "%x\n", iommu->cap);
+	return sysfs_emit(buf, "%x\n", iommu->cap);
 }
 static DEVICE_ATTR(cap, S_IRUGO, amd_iommu_show_cap, NULL);
 
@@ -1950,7 +1950,7 @@ static ssize_t amd_iommu_show_features(struct device *dev,
 				       char *buf)
 {
 	struct amd_iommu *iommu = dev_to_amd_iommu(dev);
-	return sprintf(buf, "%llx:%llx\n", iommu->features2, iommu->features);
+	return sysfs_emit(buf, "%llx:%llx\n", iommu->features2, iommu->features);
 }
 static DEVICE_ATTR(features, S_IRUGO, amd_iommu_show_features, NULL);
 

drivers/iommu/intel/iommu.c

@@ -3760,49 +3760,50 @@ static ssize_t version_show(struct device *dev,
 {
 	struct intel_iommu *iommu = dev_to_intel_iommu(dev);
 	u32 ver = readl(iommu->reg + DMAR_VER_REG);
-	return sprintf(buf, "%d:%d\n",
-		       DMAR_VER_MAJOR(ver), DMAR_VER_MINOR(ver));
+	return sysfs_emit(buf, "%d:%d\n",
+			  DMAR_VER_MAJOR(ver), DMAR_VER_MINOR(ver));
 }
 static DEVICE_ATTR_RO(version);
 
 static ssize_t address_show(struct device *dev,
 			    struct device_attribute *attr, char *buf)
 {
 	struct intel_iommu *iommu = dev_to_intel_iommu(dev);
-	return sprintf(buf, "%llx\n", iommu->reg_phys);
+	return sysfs_emit(buf, "%llx\n", iommu->reg_phys);
 }
 static DEVICE_ATTR_RO(address);
 
 static ssize_t cap_show(struct device *dev,
 			struct device_attribute *attr, char *buf)
 {
 	struct intel_iommu *iommu = dev_to_intel_iommu(dev);
-	return sprintf(buf, "%llx\n", iommu->cap);
+	return sysfs_emit(buf, "%llx\n", iommu->cap);
 }
 static DEVICE_ATTR_RO(cap);
 
 static ssize_t ecap_show(struct device *dev,
 			 struct device_attribute *attr, char *buf)
 {
 	struct intel_iommu *iommu = dev_to_intel_iommu(dev);
-	return sprintf(buf, "%llx\n", iommu->ecap);
+	return sysfs_emit(buf, "%llx\n", iommu->ecap);
 }
 static DEVICE_ATTR_RO(ecap);
 
 static ssize_t domains_supported_show(struct device *dev,
 				      struct device_attribute *attr, char *buf)
 {
 	struct intel_iommu *iommu = dev_to_intel_iommu(dev);
-	return sprintf(buf, "%ld\n", cap_ndoms(iommu->cap));
+	return sysfs_emit(buf, "%ld\n", cap_ndoms(iommu->cap));
 }
 static DEVICE_ATTR_RO(domains_supported);
 
 static ssize_t domains_used_show(struct device *dev,
 				 struct device_attribute *attr, char *buf)
 {
 	struct intel_iommu *iommu = dev_to_intel_iommu(dev);
-	return sprintf(buf, "%d\n", bitmap_weight(iommu->domain_ids,
-						  cap_ndoms(iommu->cap)));
+	return sysfs_emit(buf, "%d\n",
+			  bitmap_weight(iommu->domain_ids,
+					cap_ndoms(iommu->cap)));
 }
 static DEVICE_ATTR_RO(domains_used);
 

drivers/iommu/iommu.c

@@ -616,7 +616,7 @@ static void iommu_group_remove_file(struct iommu_group *group,
 
 static ssize_t iommu_group_show_name(struct iommu_group *group, char *buf)
 {
-	return sprintf(buf, "%s\n", group->name);
+	return sysfs_emit(buf, "%s\n", group->name);
 }
 
 /**
@@ -729,52 +729,51 @@ static ssize_t iommu_group_show_resv_regions(struct iommu_group *group,
 {
 	struct iommu_resv_region *region, *next;
 	struct list_head group_resv_regions;
-	char *str = buf;
+	int offset = 0;
 
 	INIT_LIST_HEAD(&group_resv_regions);
 	iommu_get_group_resv_regions(group, &group_resv_regions);
 
 	list_for_each_entry_safe(region, next, &group_resv_regions, list) {
-		str += sprintf(str, "0x%016llx 0x%016llx %s\n",
-			       (long long int)region->start,
-			       (long long int)(region->start +
-						region->length - 1),
-			       iommu_group_resv_type_string[region->type]);
+		offset += sysfs_emit_at(buf, offset, "0x%016llx 0x%016llx %s\n",
+					(long long)region->start,
+					(long long)(region->start +
+						    region->length - 1),
+					iommu_group_resv_type_string[region->type]);
 		kfree(region);
 	}
 
-	return (str - buf);
+	return offset;
 }
 
 static ssize_t iommu_group_show_type(struct iommu_group *group,
 				     char *buf)
 {
-	char *type = "unknown\n";
+	char *type = "unknown";
 
 	mutex_lock(&group->mutex);
 	if (group->default_domain) {
 		switch (group->default_domain->type) {
 		case IOMMU_DOMAIN_BLOCKED:
-			type = "blocked\n";
+			type = "blocked";
 			break;
 		case IOMMU_DOMAIN_IDENTITY:
-			type = "identity\n";
+			type = "identity";
 			break;
 		case IOMMU_DOMAIN_UNMANAGED:
-			type = "unmanaged\n";
+			type = "unmanaged";
 			break;
 		case IOMMU_DOMAIN_DMA:
-			type = "DMA\n";
+			type = "DMA";
 			break;
 		case IOMMU_DOMAIN_DMA_FQ:
-			type = "DMA-FQ\n";
+			type = "DMA-FQ";
 			break;
 		}
 	}
 	mutex_unlock(&group->mutex);
-	strcpy(buf, type);
 
-	return strlen(type);
+	return sysfs_emit(buf, "%s\n", type);
 }
 
 static IOMMU_GROUP_ATTR(name, S_IRUGO, iommu_group_show_name, NULL);