scsi: lpfc: Rework MIB Rx Monitor debug info logic

The kernel test robot reported the following sparse warning:

arch/arm64/include/asm/cmpxchg.h:88:1: sparse: sparse: cast truncates
   bits from constant value (369 becomes 69)

On arm64, atomic_xchg only works on 8-bit byte fields.  Thus, the macro
usage of LPFC_RXMONITOR_TABLE_IN_USE can be unintentionally truncated
leading to all logic involving the LPFC_RXMONITOR_TABLE_IN_USE macro to not
work properly.

Replace the Rx Table atomic_t indexing logic with a new
lpfc_rx_info_monitor structure that holds a circular ring buffer.  For
locking semantics, a spinlock_t is used.

Link: https://lore.kernel.org/r/20220819011736.14141-4-jsmart2021@gmail.com
Fixes: 17b27ac59224 ("scsi: lpfc: Add rx monitoring statistics")
Cc: <stable@vger.kernel.org> # v5.15+
Co-developed-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 10 insertions, 49 deletions

diff --git a/drivers/scsi/lpfc/lpfc_debugfs.c b/drivers/scsi/lpfc/lpfc_debugfs.c
index 5037ea09a810..e37b028eae5f 100644
--- a/drivers/scsi/lpfc/lpfc_debugfs.c
+++ b/drivers/scsi/lpfc/lpfc_debugfs.c
@@ -5531,7 +5531,7 @@ lpfc_rx_monitor_open(struct inode *inode, struct file *file)
 	if (!debug)
 		goto out;
 
-	debug->buffer = vmalloc(MAX_DEBUGFS_RX_TABLE_SIZE);
+	debug->buffer = vmalloc(MAX_DEBUGFS_RX_INFO_SIZE);
 	if (!debug->buffer) {
 		kfree(debug);
 		goto out;
@@ -5552,57 +5552,18 @@ lpfc_rx_monitor_read(struct file *file, char __user *buf, size_t nbytes,
 	struct lpfc_rx_monitor_debug *debug = file->private_data;
 	struct lpfc_hba *phba = (struct lpfc_hba *)debug->i_private;
 	char *buffer = debug->buffer;
-	struct rxtable_entry *entry;
-	int i, len = 0, head, tail, last, start;
-
-	head = atomic_read(&phba->rxtable_idx_head);
-	while (head == LPFC_RXMONITOR_TABLE_IN_USE) {
-		/* Table is getting updated */
-		msleep(20);
-		head = atomic_read(&phba->rxtable_idx_head);
-	}
 
-	tail = atomic_xchg(&phba->rxtable_idx_tail, head);
-	if (!phba->rxtable || head == tail) {
-		len += scnprintf(buffer + len, MAX_DEBUGFS_RX_TABLE_SIZE - len,
-				"Rxtable is empty\n");
-		goto out;
-	}
-	last = (head > tail) ?  head : LPFC_MAX_RXMONITOR_ENTRY;
-	start = tail;
-
-	len += scnprintf(buffer + len, MAX_DEBUGFS_RX_TABLE_SIZE - len,
-			"        MaxBPI    Tot_Data_CMF Tot_Data_Cmd "
-			"Tot_Data_Cmpl  Lat(us)  Avg_IO  Max_IO "
-			"Bsy IO_cnt Info BWutil(ms)\n");
-get_table:
-	for (i = start; i < last; i++) {
-		entry = &phba->rxtable[i];
-		len += scnprintf(buffer + len, MAX_DEBUGFS_RX_TABLE_SIZE - len,
-				"%3d:%12lld %12lld %12lld %12lld "
-				"%7lldus %8lld %7lld "
-				"%2d   %4d   %2d   %2d(%2d)\n",
-				i, entry->max_bytes_per_interval,
-				entry->cmf_bytes,
-				entry->total_bytes,
-				entry->rcv_bytes,
-				entry->avg_io_latency,
-				entry->avg_io_size,
-				entry->max_read_cnt,
-				entry->cmf_busy,
-				entry->io_cnt,
-				entry->cmf_info,
-				entry->timer_utilization,
-				entry->timer_interval);
+	if (!phba->rx_monitor) {
+		scnprintf(buffer, MAX_DEBUGFS_RX_INFO_SIZE,
+			  "Rx Monitor Info is empty.\n");
+	} else {
+		lpfc_rx_monitor_report(phba, phba->rx_monitor, buffer,
+				       MAX_DEBUGFS_RX_INFO_SIZE,
+				       LPFC_MAX_RXMONITOR_ENTRY);
 	}
 
-	if (head != last) {
-		start = 0;
-		last = head;
-		goto get_table;
-	}
-out:
-	return simple_read_from_buffer(buf, nbytes, ppos, buffer, len);
+	return simple_read_from_buffer(buf, nbytes, ppos, buffer,
+				       strlen(buffer));
 }
 
 static int