pm8001: add a new spinlock to protect the CCB

Patch adds a new spinlock to protect the ccb management.
It may happen that concurrent threads become the same tag value
from the 'alloc' function', the spinlock prevents this situation.

Signed-off-by: Tomas Henzl <thenzl@redhat.com>
Acked-by: Suresh Thiagarajan <Suresh.Thiagarajan@pmcs.com>
Acked-by: Jack Wang <xjtuwjp@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

3 files changed, 8 insertions, 1 deletions

diff --git a/drivers/scsi/pm8001/pm8001_init.c b/drivers/scsi/pm8001/pm8001_init.c
index aad060aa3c0c..acef7d6a5790 100644
--- a/drivers/scsi/pm8001/pm8001_init.c
+++ b/drivers/scsi/pm8001/pm8001_init.c
@@ -246,6 +246,7 @@ static int pm8001_alloc(struct pm8001_hba_info *pm8001_ha,
 {
         int i;
         spin_lock_init(&pm8001_ha->lock);
+        spin_lock_init(&pm8001_ha->bitmap_lock);
         PM8001_INIT_DBG(pm8001_ha,
                 pm8001_printk("pm8001_alloc: PHY:%x\n",
                                 pm8001_ha->chip->n_phy));
diff --git a/drivers/scsi/pm8001/pm8001_sas.c b/drivers/scsi/pm8001/pm8001_sas.c
index be55859042cd..34cea8291772 100644
--- a/drivers/scsi/pm8001/pm8001_sas.c
+++ b/drivers/scsi/pm8001/pm8001_sas.c
@@ -77,11 +77,16 @@ inline int pm8001_tag_alloc(struct pm8001_hba_info *pm8001_ha, u32 *tag_out)
 {
         unsigned int tag;
         void *bitmap = pm8001_ha->tags;
+        unsigned long flags;
 
+        spin_lock_irqsave(&pm8001_ha->bitmap_lock, flags);
         tag = find_first_zero_bit(bitmap, pm8001_ha->tags_num);
-        if (tag >= pm8001_ha->tags_num)
+        if (tag >= pm8001_ha->tags_num) {
+                spin_unlock_irqrestore(&pm8001_ha->bitmap_lock, flags);
                 return -SAS_QUEUE_FULL;
+        }
         set_bit(tag, bitmap);
+        spin_unlock_irqrestore(&pm8001_ha->bitmap_lock, flags);
         *tag_out = tag;
         return 0;
 }
diff --git a/drivers/scsi/pm8001/pm8001_sas.h b/drivers/scsi/pm8001/pm8001_sas.h
index 14106adec009..f6b2ac59dae4 100644
--- a/drivers/scsi/pm8001/pm8001_sas.h
+++ b/drivers/scsi/pm8001/pm8001_sas.h
@@ -475,6 +475,7 @@ struct pm8001_hba_info {
         struct list_head        list;
         unsigned long           flags;
         spinlock_t              lock;/* host-wide lock */
+        spinlock_t              bitmap_lock;
         struct pci_dev          *pdev;/* our device */
         struct device           *dev;
         struct pm8001_hba_memspace io_mem[6];