2017-06-19 02:40:42

by Jia-Ju Bai

[permalink] [raw]
Subject: [PATCH] qla4xxx: Fix a sleep-in-atomic bug in qla4_82xx_crb_win_lock

The driver may sleep under a write spin lock, the function call path is:
qla4_82xx_wr_32 (acquire the lock)
qla4_82xx_crb_win_lock
schedule or cpu_relax

To fix it, the lock is released before "schedule" and "cpu_relax",
and the lock is acquired again after "schedule" and "cpu_relax".

Signed-off-by: Jia-Ju Bai <[email protected]>
---
drivers/scsi/qla4xxx/ql4_glbl.h | 2 +-
drivers/scsi/qla4xxx/ql4_nx.c | 8 +++++---
2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/qla4xxx/ql4_glbl.h b/drivers/scsi/qla4xxx/ql4_glbl.h
index bce96a5..b723bef 100644
--- a/drivers/scsi/qla4xxx/ql4_glbl.h
+++ b/drivers/scsi/qla4xxx/ql4_glbl.h
@@ -115,7 +115,7 @@ uint8_t qla4xxx_update_local_ifcb(struct scsi_qla_host *ha,
void qla4_82xx_queue_iocb(struct scsi_qla_host *ha);
void qla4_82xx_complete_iocb(struct scsi_qla_host *ha);

-int qla4_82xx_crb_win_lock(struct scsi_qla_host *);
+int qla4_82xx_crb_win_lock(struct scsi_qla_host *, unsigned long *);
void qla4_82xx_crb_win_unlock(struct scsi_qla_host *);
int qla4_82xx_pci_get_crb_addr_2M(struct scsi_qla_host *, ulong *);
void qla4_82xx_wr_32(struct scsi_qla_host *, ulong, u32);
diff --git a/drivers/scsi/qla4xxx/ql4_nx.c b/drivers/scsi/qla4xxx/ql4_nx.c
index e91abb3..1cf5f4a 100644
--- a/drivers/scsi/qla4xxx/ql4_nx.c
+++ b/drivers/scsi/qla4xxx/ql4_nx.c
@@ -386,7 +386,7 @@

if (rv == 1) {
write_lock_irqsave(&ha->hw_lock, flags);
- qla4_82xx_crb_win_lock(ha);
+ qla4_82xx_crb_win_lock(ha, &flags);
qla4_82xx_pci_set_crbwindow_2M(ha, &off);
}

@@ -410,7 +410,7 @@ uint32_t qla4_82xx_rd_32(struct scsi_qla_host *ha, ulong off)

if (rv == 1) {
write_lock_irqsave(&ha->hw_lock, flags);
- qla4_82xx_crb_win_lock(ha);
+ qla4_82xx_crb_win_lock(ha, &flags);
qla4_82xx_pci_set_crbwindow_2M(ha, &off);
}
data = readl((void __iomem *)off);
@@ -476,7 +476,7 @@ int qla4_82xx_md_wr_32(struct scsi_qla_host *ha, uint32_t off, uint32_t data)

#define CRB_WIN_LOCK_TIMEOUT 100000000

-int qla4_82xx_crb_win_lock(struct scsi_qla_host *ha)
+int qla4_82xx_crb_win_lock(struct scsi_qla_host *ha, unsigned long *flags)
{
int i;
int done = 0, timeout = 0;
@@ -491,6 +491,7 @@ int qla4_82xx_crb_win_lock(struct scsi_qla_host *ha)

timeout++;

+ write_unlock_irqrestore(&ha->hw_lock, *flags);
/* Yield CPU */
if (!in_interrupt())
schedule();
@@ -498,6 +499,7 @@ int qla4_82xx_crb_win_lock(struct scsi_qla_host *ha)
for (i = 0; i < 20; i++)
cpu_relax(); /*This a nop instr on i386*/
}
+ write_lock_irqsave(&ha->hw_lock, *flags);
}
qla4_82xx_wr_32(ha, QLA82XX_CRB_WIN_LOCK_ID, ha->func_num);
return 0;
--
1.7.9.5