From 77dd7d7b344283a3bce334d0f43fc2c0629ffe48 Mon Sep 17 00:00:00 2001 From: Dick Kennedy Date: Mon, 6 Jul 2020 13:42:46 -0700 Subject: scsi: lpfc: Fix less-than-zero comparison of unsigned value The expression start_idx - dbg_cnt is evaluated using unsigned int arthithmetic (since these variables are unsigned ints) and hence can never be less than zero, so the less than comparison is never true. Rewrite the expression to check for start_idx being less than dbg_cnt. After the logic was corrected, temp_idx wasn't working correctly. So fix it as well. Link: https://lore.kernel.org/r/20200706204246.130416-1-jsmart2021@gmail.com Fixes: 372c187b8a70 ("scsi: lpfc: Add an internal trace log buffer") CC: Colin Ian King Signed-off-by: Dick Kennedy Signed-off-by: James Smart Signed-off-by: Martin K. Petersen Addresses-Coverity: ("Unsigned compared against 0") --- drivers/scsi/lpfc/lpfc_init.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c index 4ba8202d391b..f3656bdcb582 100644 --- a/drivers/scsi/lpfc/lpfc_init.c +++ b/drivers/scsi/lpfc/lpfc_init.c @@ -14161,12 +14161,10 @@ void lpfc_dmp_dbg(struct lpfc_hba *phba) if ((start_idx + dbg_cnt) > (DBG_LOG_SZ - 1)) { temp_idx = (start_idx + dbg_cnt) % DBG_LOG_SZ; } else { - if ((start_idx - dbg_cnt) < 0) { + if (start_idx < dbg_cnt) start_idx = DBG_LOG_SZ - (dbg_cnt - start_idx); - temp_idx = 0; - } else { + else start_idx -= dbg_cnt; - } } } dev_info(&phba->pcidev->dev, "start %d end %d cnt %d\n", @@ -14174,7 +14172,7 @@ void lpfc_dmp_dbg(struct lpfc_hba *phba) for (i = 0; i < dbg_cnt; i++) { if ((start_idx + i) < DBG_LOG_SZ) - temp_idx = (start_idx + i) % (DBG_LOG_SZ - 1); + temp_idx = (start_idx + i) % DBG_LOG_SZ; else temp_idx = j++; rem_nsec = do_div(phba->dbg_log[temp_idx].t_ns, NSEC_PER_SEC); -- cgit v1.2.3