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cnic: Prevent status block race conditions with hardware 

The status block index is used to acknowledge interrupt events and must
be read before checking for the interrupt events, so we need to add rmb()
to guarantee that.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Michael Chan 2011-03-02 13:00:49 +00:00 committed by David S. Miller
parent 1707be1be1
commit 107c3f4d42
1 changed files with 8 additions and 0 deletions
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8
drivers/net/cnic.c
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@ -2760,6 +2760,8 @@ static u32 cnic_service_bnx2_queues(struct cnic_dev *dev)
u32 status_idx = (u16) *cp->kcq1.status_idx_ptr;
int kcqe_cnt;
/* status block index must be read before reading other fields */
rmb();
cp->kwq_con_idx = *cp->kwq_con_idx_ptr;
while ((kcqe_cnt = cnic_get_kcqes(dev, &cp->kcq1))) {
@ -2770,6 +2772,8 @@ static u32 cnic_service_bnx2_queues(struct cnic_dev *dev)
barrier();
if (status_idx != *cp->kcq1.status_idx_ptr) {
status_idx = (u16) *cp->kcq1.status_idx_ptr;
/* status block index must be read first */
rmb();
cp->kwq_con_idx = *cp->kwq_con_idx_ptr;
} else
break;
@ -2888,6 +2892,8 @@ static u32 cnic_service_bnx2x_kcq(struct cnic_dev *dev, struct kcq_info *info)
u32 last_status = *info->status_idx_ptr;
int kcqe_cnt;
/* status block index must be read before reading the KCQ */
rmb();
while ((kcqe_cnt = cnic_get_kcqes(dev, info))) {
service_kcqes(dev, kcqe_cnt);
@ -2898,6 +2904,8 @@ static u32 cnic_service_bnx2x_kcq(struct cnic_dev *dev, struct kcq_info *info)
break;
last_status = *info->status_idx_ptr;
/* status block index must be read before reading the KCQ */
rmb();
}
return last_status;
}