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- In _iflib_fl_refill(), don't mark an RX buffer as available in the

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corresponding bitmap before adding an mbuf has actually succeeded.
  Previously, m_gethdr(M_NOWAIT, ...) failing caused a "hole" in the
  RX ring but not in its bitmap. One implication of such a hole was
  that in a subsequent call to _iflib_fl_refill() with the RX buffer
  accounting still indicating another reclaimable buffer, bit_ffc(3)
  nevertheless returned -1 in frag_idx which in turn caused havoc
  when used as an index. Thus, additionally assert that frag_idx is
  0 or greater.
  Another possible consequence of a hole in the RX ring was a NULL-
  dereference when trying to use the unallocated mbuf, for example
  in iflib_rxd_pkt_get().

  While at it, make the variable declarations in _iflib_fl_refill()
  conform to style(9) and remove redundant checks already performed
  by bit_ffc{,_at}(3).

- In iflib_queues_alloc(), don't pass redundant M_ZERO to bit_alloc(3).

Reported and tested by: pho
This commit is contained in:
Marius Strobl 2019-01-26 21:35:51 +00:00
parent 4268f3b3e0
commit 3db348b54a
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=343481
1 changed files with 16 additions and 15 deletions
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31
sys/net/iflib.c
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@ -1921,27 +1921,27 @@ _rxq_refill_cb(void *arg, bus_dma_segment_t *segs, int nseg, int error)
static void
_iflib_fl_refill(if_ctx_t ctx, iflib_fl_t fl, int count)
{
struct mbuf *m;
int idx, frag_idx = fl->ifl_fragidx;
int pidx = fl->ifl_pidx;
caddr_t cl, *sd_cl;
struct mbuf **sd_m;
struct if_rxd_update iru;
struct rxq_refill_cb_arg cb_arg;
struct mbuf *m;
caddr_t cl, *sd_cl;
struct mbuf **sd_m;
bus_dmamap_t *sd_map;
int n, i = 0;
bus_addr_t bus_addr, *sd_ba;
int err;
int err, frag_idx, i, idx, n, pidx;
qidx_t credits;
sd_m = fl->ifl_sds.ifsd_m;
sd_map = fl->ifl_sds.ifsd_map;
sd_cl = fl->ifl_sds.ifsd_cl;
sd_ba = fl->ifl_sds.ifsd_ba;
pidx = fl->ifl_pidx;
idx = pidx;
frag_idx = fl->ifl_fragidx;
credits = fl->ifl_credits;
n = count;
i = 0;
n = count;
MPASS(n > 0);
MPASS(credits + n <= fl->ifl_size);
@ -1963,9 +1963,11 @@ _iflib_fl_refill(if_ctx_t ctx, iflib_fl_t fl, int count)
*
* If the cluster is still set then we know a minimum sized packet was received
*/
bit_ffc_at(fl->ifl_rx_bitmap, frag_idx, fl->ifl_size, &frag_idx);
if ((frag_idx < 0) || (frag_idx >= fl->ifl_size))
bit_ffc(fl->ifl_rx_bitmap, fl->ifl_size, &frag_idx);
bit_ffc_at(fl->ifl_rx_bitmap, frag_idx, fl->ifl_size,
&frag_idx);
if (frag_idx < 0)
bit_ffc(fl->ifl_rx_bitmap, fl->ifl_size, &frag_idx);
MPASS(frag_idx >= 0);
if ((cl = sd_cl[frag_idx]) == NULL) {
if ((cl = m_cljget(NULL, M_NOWAIT, fl->ifl_buf_size)) == NULL)
break;
@ -1995,12 +1997,12 @@ _iflib_fl_refill(if_ctx_t ctx, iflib_fl_t fl, int count)
bus_addr = sd_ba[frag_idx];
}
bit_set(fl->ifl_rx_bitmap, frag_idx);
MPASS(sd_m[frag_idx] == NULL);
if ((m = m_gethdr(M_NOWAIT, MT_NOINIT)) == NULL) {
break;
}
sd_m[frag_idx] = m;
bit_set(fl->ifl_rx_bitmap, frag_idx);
#if MEMORY_LOGGING
fl->ifl_m_enqueued++;
#endif
@ -2025,7 +2027,6 @@ _iflib_fl_refill(if_ctx_t ctx, iflib_fl_t fl, int count)
fl->ifl_pidx = idx;
fl->ifl_credits = credits;
}
}
if (i) {
@ -4896,7 +4897,6 @@ iflib_device_deregister(if_ctx_t ctx)
for (j = 0, fl = rxq->ifr_fl; j < rxq->ifr_nfl; j++, fl++)
free(fl->ifl_rx_bitmap, M_IFLIB);
}
tqg = qgroup_if_config_tqg;
if (ctx->ifc_admin_task.gt_uniq != NULL)
@ -5304,7 +5304,8 @@ iflib_queues_alloc(if_ctx_t ctx)
}
for (j = 0, fl = rxq->ifr_fl; j < rxq->ifr_nfl; j++, fl++)
fl->ifl_rx_bitmap = bit_alloc(fl->ifl_size, M_IFLIB, M_WAITOK|M_ZERO);
fl->ifl_rx_bitmap = bit_alloc(fl->ifl_size, M_IFLIB,
M_WAITOK);
}
/* TXQs */