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Ring the freelist doorbell from within refill_fl. While here, fix a bug

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that could have allowed the hardware pidx to reach the cidx even though
the freelist isn't empty.  (Haven't actually seen this but it was there
waiting to happen..)

MFC after:	1 week
This commit is contained in:
Navdeep Parhar 2011-04-20 23:20:00 +00:00
parent caa7ccdc54
commit fb12416c9f
1 changed files with 20 additions and 16 deletions
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36
sys/dev/cxgbe/t4_sge.c
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@ -114,7 +114,7 @@ static void oneseg_dma_callback(void *, bus_dma_segment_t *, int, int);
static inline bool is_new_response(const struct sge_iq *, struct rsp_ctrl **);
static inline void iq_next(struct sge_iq *);
static inline void ring_fl_db(struct adapter *, struct sge_fl *);
static void refill_fl(struct sge_fl *, int);
static void refill_fl(struct adapter *, struct sge_fl *, int, int);
static int alloc_fl_sdesc(struct sge_fl *);
static void free_fl_sdesc(struct sge_fl *);
static int alloc_tx_maps(struct sge_txq *);
@ -763,9 +763,7 @@ t4_eth_rx(void *arg)
FL_LOCK(fl);
fl->needed += i;
if (fl->needed >= 32)
refill_fl(fl, 64);
if (fl->pending >= 32)
ring_fl_db(sc, fl);
refill_fl(sc, fl, 64, 32);
FL_UNLOCK(fl);
nextdesc: ndescs++;
@ -793,9 +791,7 @@ nextdesc: ndescs++;
FL_LOCK(fl);
if (fl->needed >= 32)
refill_fl(fl, 128);
if (fl->pending >= 8)
ring_fl_db(sc, fl);
refill_fl(sc, fl, 128, 8);
FL_UNLOCK(fl);
}
@ -1179,7 +1175,7 @@ alloc_iq_fl(struct port_info *pi, struct sge_iq *iq, struct sge_fl *fl,
rc);
return (rc);
}
fl->needed = fl->cap - 1; /* one less to avoid cidx = pidx */
fl->needed = fl->cap;
c.iqns_to_fl0congen =
htobe32(V_FW_IQ_CMD_FL0HOSTFCMODE(X_HOSTFCMODE_NONE));
@ -1222,9 +1218,7 @@ alloc_iq_fl(struct port_info *pi, struct sge_iq *iq, struct sge_fl *fl,
sc->sge.eqmap[cntxt_id] = (void *)fl;
FL_LOCK(fl);
refill_fl(fl, -1);
if (fl->pending >= 8)
ring_fl_db(sc, fl);
refill_fl(sc, fl, -1, 8);
FL_UNLOCK(fl);
}
@ -1692,24 +1686,31 @@ iq_next(struct sge_iq *iq)
}
}
#define FL_HW_IDX(x) ((x) >> 3)
static inline void
ring_fl_db(struct adapter *sc, struct sge_fl *fl)
{
int ndesc = fl->pending / 8;
/* Caller responsible for ensuring there's something useful to do */
KASSERT(ndesc > 0, ("%s called with no useful work to do.", __func__));
if (FL_HW_IDX(fl->pidx) == FL_HW_IDX(fl->cidx))
ndesc--; /* hold back one credit */
if (ndesc <= 0)
return; /* nothing to do */
wmb();
t4_write_reg(sc, MYPF_REG(A_SGE_PF_KDOORBELL), F_DBPRIO |
V_QID(fl->cntxt_id) | V_PIDX(ndesc));
fl->pending &= 7;
fl->pending -= ndesc * 8;
}
/*
* Fill up the freelist by upto nbufs and ring its doorbell if the number of
* buffers ready to be handed to the hardware >= dbthresh.
*/
static void
refill_fl(struct sge_fl *fl, int nbufs)
refill_fl(struct adapter *sc, struct sge_fl *fl, int nbufs, int dbthresh)
{
__be64 *d = &fl->desc[fl->pidx];
struct fl_sdesc *sd = &fl->sdesc[fl->pidx];
@ -1800,6 +1801,9 @@ refill_fl(struct sge_fl *fl, int nbufs)
d = fl->desc;
}
}
if (fl->pending >= dbthresh)
ring_fl_db(sc, fl);
}
static int