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cnic: Prevent status block race conditions with hardware

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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;
}