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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>
This commit is contained in:
David S. Miller
2007-10-11 18:08:29 -07:00
parent b08d6cb22c
commit 6f53576316
3 changed files with 82 additions and 42 deletions
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17
drivers/net/sky2.c
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@@ -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);
@@ -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.
*/
@@ -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;
}