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bnx2x: napi_poll budget check

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Check the napi_poll budget only when updating it. Also add a comment to explain
the rmb

Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eilon Greenstein 2009-03-02 07:59:45 +00:00 committed by David S. Miller
parent 7961f79123
commit 8534f32c2f
1 changed files with 18 additions and 4 deletions
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22
drivers/net/bnx2x_main.c
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@ -10068,14 +10068,27 @@ static int bnx2x_poll(struct napi_struct *napi, int budget)
if (bnx2x_has_tx_work(fp))
bnx2x_tx_int(fp);
if (bnx2x_has_rx_work(fp))
if (bnx2x_has_rx_work(fp)) {
work_done = bnx2x_rx_int(fp, budget);
rmb(); /* BNX2X_HAS_WORK() reads the status block */
/* must not complete if we consumed full budget */
if (work_done >= budget)
goto poll_again;
}
/* must not complete if we consumed full budget */
if ((work_done < budget) && !BNX2X_HAS_WORK(fp)) {
/* BNX2X_HAS_WORK() reads the status block, thus we need to
* ensure that status block indices have been actually read
* (bnx2x_update_fpsb_idx) prior to this check (BNX2X_HAS_WORK)
* so that we won't write the "newer" value of the status block to IGU
* (if there was a DMA right after BNX2X_HAS_WORK and
* if there is no rmb, the memory reading (bnx2x_update_fpsb_idx)
* may be postponed to right before bnx2x_ack_sb). In this case
* there will never be another interrupt until there is another update
* of the status block, while there is still unhandled work.
*/
rmb();
if (!BNX2X_HAS_WORK(fp)) {
#ifdef BNX2X_STOP_ON_ERROR
poll_panic:
#endif
@ -10087,6 +10100,7 @@ poll_panic:
le16_to_cpu(fp->fp_c_idx), IGU_INT_ENABLE, 1);
}
poll_again:
return work_done;
}