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[NET]: Fix NAPI completion handling in some drivers.
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In order for the list handling in net_rx_action() to be
correct, drivers must follow certain rules as stated by
this comment in net_rx_action():

		/* Drivers must not modify the NAPI state if they
		 * consume the entire weight.  In such cases this code
		 * still "owns" the NAPI instance and therefore can
		 * move the instance around on the list at-will.
		 */

A few drivers do not do this because they mix the budget checks
with reading hardware state, resulting in crashes like the one
reported by takano@axe-inc.co.jp.

BNX2 and TG3 are taken care of here, SKY2 fix is from Stephen
Hemminger.

Signed-off-by: David S. Miller <davem@davemloft.net>
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David S. Miller committed Oct 12, 2007
1 parent b08d6cb commit 6f53576
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Showing 3 changed files with 82 additions and 42 deletions.
52 changes: 32 additions & 20 deletions drivers/net/bnx2.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2633,15 +2633,11 @@ bnx2_has_work(struct bnx2 *bp)
return 0;
}

static int
bnx2_poll(struct napi_struct *napi, int budget)
static int bnx2_poll_work(struct bnx2 *bp, int work_done, int budget)
{
struct bnx2 *bp = container_of(napi, struct bnx2, napi);
struct net_device *dev = bp->dev;
struct status_block *sblk = bp->status_blk;
u32 status_attn_bits = sblk->status_attn_bits;
u32 status_attn_bits_ack = sblk->status_attn_bits_ack;
int work_done = 0;

if ((status_attn_bits & STATUS_ATTN_EVENTS) !=
(status_attn_bits_ack & STATUS_ATTN_EVENTS)) {
Expand All @@ -2660,27 +2656,43 @@ bnx2_poll(struct napi_struct *napi, int budget)
bnx2_tx_int(bp);

if (bp->status_blk->status_rx_quick_consumer_index0 != bp->hw_rx_cons)
work_done = bnx2_rx_int(bp, budget);
work_done += bnx2_rx_int(bp, budget - work_done);

bp->last_status_idx = bp->status_blk->status_idx;
rmb();
return work_done;
}

static int bnx2_poll(struct napi_struct *napi, int budget)
{
struct bnx2 *bp = container_of(napi, struct bnx2, napi);
int work_done = 0;

while (1) {
work_done = bnx2_poll_work(bp, work_done, budget);

if (!bnx2_has_work(bp)) {
netif_rx_complete(dev, napi);
if (likely(bp->flags & USING_MSI_FLAG)) {
if (unlikely(work_done >= budget))
break;

if (likely(!bnx2_has_work(bp))) {
bp->last_status_idx = bp->status_blk->status_idx;
rmb();

netif_rx_complete(bp->dev, napi);
if (likely(bp->flags & USING_MSI_FLAG)) {
REG_WR(bp, BNX2_PCICFG_INT_ACK_CMD,
BNX2_PCICFG_INT_ACK_CMD_INDEX_VALID |
bp->last_status_idx);
return 0;
}
REG_WR(bp, BNX2_PCICFG_INT_ACK_CMD,
BNX2_PCICFG_INT_ACK_CMD_INDEX_VALID |
BNX2_PCICFG_INT_ACK_CMD_MASK_INT |
bp->last_status_idx);
return 0;
}
REG_WR(bp, BNX2_PCICFG_INT_ACK_CMD,
BNX2_PCICFG_INT_ACK_CMD_INDEX_VALID |
BNX2_PCICFG_INT_ACK_CMD_MASK_INT |
bp->last_status_idx);

REG_WR(bp, BNX2_PCICFG_INT_ACK_CMD,
BNX2_PCICFG_INT_ACK_CMD_INDEX_VALID |
bp->last_status_idx);
REG_WR(bp, BNX2_PCICFG_INT_ACK_CMD,
BNX2_PCICFG_INT_ACK_CMD_INDEX_VALID |
bp->last_status_idx);
break;
}
}

return work_done;
Expand Down
17 changes: 13 additions & 4 deletions drivers/net/sky2.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2606,7 +2606,7 @@ static int sky2_poll(struct napi_struct *napi, int work_limit)
{
struct sky2_hw *hw = container_of(napi, struct sky2_hw, napi);
u32 status = sky2_read32(hw, B0_Y2_SP_EISR);
int work_done;
int work_done = 0;

if (unlikely(status & Y2_IS_ERROR))
sky2_err_intr(hw, status);
Expand All @@ -2617,10 +2617,16 @@ static int sky2_poll(struct napi_struct *napi, int work_limit)
if (status & Y2_IS_IRQ_PHY2)
sky2_phy_intr(hw, 1);

work_done = sky2_status_intr(hw, work_limit);
for(;;) {
work_done += sky2_status_intr(hw, work_limit);

if (work_done >= work_limit)
break;

/* More work? */
if (hw->st_idx != sky2_read16(hw, STAT_PUT_IDX))
continue;

/* More work? */
if (hw->st_idx == sky2_read16(hw, STAT_PUT_IDX)) {
/* Bug/Errata workaround?
* Need to kick the TX irq moderation timer.
*/
Expand All @@ -2631,7 +2637,10 @@ static int sky2_poll(struct napi_struct *napi, int work_limit)

napi_complete(napi);
sky2_read32(hw, B0_Y2_SP_LISR);
break;

}

return work_done;
}

Expand Down
55 changes: 37 additions & 18 deletions drivers/net/tg3.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3555,12 +3555,9 @@ static int tg3_rx(struct tg3 *tp, int budget)
return received;
}

static int tg3_poll(struct napi_struct *napi, int budget)
static int tg3_poll_work(struct tg3 *tp, int work_done, int budget)
{
struct tg3 *tp = container_of(napi, struct tg3, napi);
struct net_device *netdev = tp->dev;
struct tg3_hw_status *sblk = tp->hw_status;
int work_done = 0;

/* handle link change and other phy events */
if (!(tp->tg3_flags &
Expand All @@ -3578,33 +3575,55 @@ static int tg3_poll(struct napi_struct *napi, int budget)
/* run TX completion thread */
if (sblk->idx[0].tx_consumer != tp->tx_cons) {
tg3_tx(tp);
if (unlikely(tp->tg3_flags & TG3_FLAG_TX_RECOVERY_PENDING)) {
netif_rx_complete(netdev, napi);
schedule_work(&tp->reset_task);
if (unlikely(tp->tg3_flags & TG3_FLAG_TX_RECOVERY_PENDING))
return 0;
}
}

/* run RX thread, within the bounds set by NAPI.
* All RX "locking" is done by ensuring outside
* code synchronizes with tg3->napi.poll()
*/
if (sblk->idx[0].rx_producer != tp->rx_rcb_ptr)
work_done = tg3_rx(tp, budget);
work_done += tg3_rx(tp, budget - work_done);

if (tp->tg3_flags & TG3_FLAG_TAGGED_STATUS) {
tp->last_tag = sblk->status_tag;
rmb();
} else
sblk->status &= ~SD_STATUS_UPDATED;
return work_done;
}

/* if no more work, tell net stack and NIC we're done */
if (!tg3_has_work(tp)) {
netif_rx_complete(netdev, napi);
tg3_restart_ints(tp);
static int tg3_poll(struct napi_struct *napi, int budget)
{
struct tg3 *tp = container_of(napi, struct tg3, napi);
int work_done = 0;

while (1) {
work_done = tg3_poll_work(tp, work_done, budget);

if (unlikely(tp->tg3_flags & TG3_FLAG_TX_RECOVERY_PENDING))
goto tx_recovery;

if (unlikely(work_done >= budget))
break;

if (likely(!tg3_has_work(tp))) {
struct tg3_hw_status *sblk = tp->hw_status;

if (tp->tg3_flags & TG3_FLAG_TAGGED_STATUS) {
tp->last_tag = sblk->status_tag;
rmb();
} else
sblk->status &= ~SD_STATUS_UPDATED;

netif_rx_complete(tp->dev, napi);
tg3_restart_ints(tp);
break;
}
}

return work_done;

tx_recovery:
netif_rx_complete(tp->dev, napi);
schedule_work(&tp->reset_task);
return 0;
}

static void tg3_irq_quiesce(struct tg3 *tp)
Expand Down

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