git: c930816b7671 - stable/13 - cxgbe(4): Save proper zone index on low memory in refill_fl().

[Navdeep Parhar]

The branch stable/13 has been updated by np:

URL: https://cgit.FreeBSD.org/src/commit/?id=c930816b76713623ccdef09d682e41266c1d724f

commit c930816b76713623ccdef09d682e41266c1d724f
Author:     Alexander Motin <mav at FreeBSD.org>
AuthorDate: 2021-02-17 02:15:28 +0000
Commit:     Navdeep Parhar <np at FreeBSD.org>
CommitDate: 2021-02-22 23:51:58 +0000

    cxgbe(4): Save proper zone index on low memory in refill_fl().
    
    When refill_fl() fails to allocate large (9/16KB) mbuf cluster, it
    falls back to safe (4KB) ones.  But it still saved into sd->zidx
    the original fl->zidx instead of fl->safe_zidx.  It caused problems
    with the later use of that cluster, including memory and/or data
    corruption.
    
    While there, make refill_fl() to use the safe zone for all following
    clusters for the call, since it is unlikely that large succeed.
    
    MFC after:      3 days
    Sponsored by:   iXsystems, Inc.
    Reviewed by:    np, jhb
    Differential Revision:  https://reviews.freebsd.org/D28716
    
    (cherry picked from commit 294e62bebf36f873fd083d2fe8edd78919dda4e8)
---
 sys/dev/cxgbe/t4_sge.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/sys/dev/cxgbe/t4_sge.c b/sys/dev/cxgbe/t4_sge.c
index 45f07358f0db..d16f17c45614 100644
--- a/sys/dev/cxgbe/t4_sge.c
+++ b/sys/dev/cxgbe/t4_sge.c
@@ -4524,7 +4524,7 @@ refill_fl(struct adapter *sc, struct sge_fl *fl, int n)
 	caddr_t cl;
 	struct rx_buf_info *rxb;
 	struct cluster_metadata *clm;
-	uint16_t max_pidx;
+	uint16_t max_pidx, zidx = fl->zidx;
 	uint16_t hw_cidx = fl->hw_cidx;		/* stable snapshot */
 
 	FL_LOCK_ASSERT_OWNED(fl);
@@ -4540,6 +4540,7 @@ refill_fl(struct adapter *sc, struct sge_fl *fl, int n)
 
 	d = &fl->desc[fl->pidx];
 	sd = &fl->sdesc[fl->pidx];
+	rxb = &sc->sge.rx_buf_info[zidx];
 
 	while (n > 0) {
 
@@ -4573,11 +4574,11 @@ refill_fl(struct adapter *sc, struct sge_fl *fl, int n)
 			sd->cl = NULL;	/* gave up my reference */
 		}
 		MPASS(sd->cl == NULL);
-		rxb = &sc->sge.rx_buf_info[fl->zidx];
 		cl = uma_zalloc(rxb->zone, M_NOWAIT);
 		if (__predict_false(cl == NULL)) {
-			if (fl->zidx != fl->safe_zidx) {
-				rxb = &sc->sge.rx_buf_info[fl->safe_zidx];
+			if (zidx != fl->safe_zidx) {
+				zidx = fl->safe_zidx;
+				rxb = &sc->sge.rx_buf_info[zidx];
 				cl = uma_zalloc(rxb->zone, M_NOWAIT);
 			}
 			if (cl == NULL)
@@ -4588,7 +4589,7 @@ refill_fl(struct adapter *sc, struct sge_fl *fl, int n)
 
 		pa = pmap_kextract((vm_offset_t)cl);
 		sd->cl = cl;
-		sd->zidx = fl->zidx;
+		sd->zidx = zidx;
 
 		if (fl->flags & FL_BUF_PACKING) {
 			*d = htobe64(pa | rxb->hwidx2);