target: Convert se_device statistics to atomic_long_t

This patch converts the handful of se_device statistics to type
atomic_long_t, instead of using se_device->stats_lock when
incrementing these values.

More importantly, go ahead and drop the spinlock usage within
transport_lookup_cmd_lun() fast-path code.

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 9 insertions, 6 deletions

diff --git a/drivers/target/target_core_stat.c b/drivers/target/target_core_stat.c
index 632665c026a8..03538994d2f7 100644
--- a/drivers/target/target_core_stat.c
+++ b/drivers/target/target_core_stat.c
@@ -213,7 +213,8 @@ static ssize_t target_stat_scsi_tgt_dev_show_attr_resets(
 	struct se_device *dev =
 		container_of(sgrps, struct se_device, dev_stat_grps);
 
-	return snprintf(page, PAGE_SIZE, "%u\n", dev->num_resets);
+	return snprintf(page, PAGE_SIZE, "%lu\n",
+			atomic_long_read(&dev->num_resets));
 }
 DEV_STAT_SCSI_TGT_DEV_ATTR_RO(resets);
 
@@ -396,8 +397,8 @@ static ssize_t target_stat_scsi_lu_show_attr_num_cmds(
 		container_of(sgrps, struct se_device, dev_stat_grps);
 
 	/* scsiLuNumCommands */
-	return snprintf(page, PAGE_SIZE, "%llu\n",
-			(unsigned long long)dev->num_cmds);
+	return snprintf(page, PAGE_SIZE, "%lu\n",
+			atomic_long_read(&dev->num_cmds));
 }
 DEV_STAT_SCSI_LU_ATTR_RO(num_cmds);
 
@@ -408,7 +409,8 @@ static ssize_t target_stat_scsi_lu_show_attr_read_mbytes(
 		container_of(sgrps, struct se_device, dev_stat_grps);
 
 	/* scsiLuReadMegaBytes */
-	return snprintf(page, PAGE_SIZE, "%u\n", (u32)(dev->read_bytes >> 20));
+	return snprintf(page, PAGE_SIZE, "%lu\n",
+			atomic_long_read(&dev->read_bytes) >> 20);
 }
 DEV_STAT_SCSI_LU_ATTR_RO(read_mbytes);
 
@@ -419,7 +421,8 @@ static ssize_t target_stat_scsi_lu_show_attr_write_mbytes(
 		container_of(sgrps, struct se_device, dev_stat_grps);
 
 	/* scsiLuWrittenMegaBytes */
-	return snprintf(page, PAGE_SIZE, "%u\n", (u32)(dev->write_bytes >> 20));
+	return snprintf(page, PAGE_SIZE, "%lu\n",
+			atomic_long_read(&dev->write_bytes) >> 20);
 }
 DEV_STAT_SCSI_LU_ATTR_RO(write_mbytes);
 
@@ -430,7 +433,7 @@ static ssize_t target_stat_scsi_lu_show_attr_resets(
 		container_of(sgrps, struct se_device, dev_stat_grps);
 
 	/* scsiLuInResets */
-	return snprintf(page, PAGE_SIZE, "%u\n", dev->num_resets);
+	return snprintf(page, PAGE_SIZE, "%lu\n", atomic_long_read(&dev->num_resets));
 }
 DEV_STAT_SCSI_LU_ATTR_RO(resets);