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pm8001: add a new spinlock to protect the CCB

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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>
This commit is contained in:
Tomas Henzl 2014-07-09 17:21:01 +05:30 committed by Christoph Hellwig
parent 5533abca06
commit 646cdf0083
3 changed files with 8 additions and 1 deletions
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1
drivers/scsi/pm8001/pm8001_init.c
View file

@ -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));

7
drivers/scsi/pm8001/pm8001_sas.c
View file

@ -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;
}

1
drivers/scsi/pm8001/pm8001_sas.h
View file

@ -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];