git: 3ff0dc1af85e - main - vmxnet3: make descriptor count checks more robust

The branch main has been updated by kp:

URL: https://cgit.FreeBSD.org/src/commit/?id=3ff0dc1af85e253b83127ea2417a22a7b2c31f27

commit 3ff0dc1af85e253b83127ea2417a22a7b2c31f27
Author:     Kristof Provost <kp@FreeBSD.org>
AuthorDate: 2024-06-10 08:47:38 +0000
Commit:     Kristof Provost <kp@FreeBSD.org>
CommitDate: 2024-06-10 09:04:47 +0000

    vmxnet3: make descriptor count checks more robust
    
    When we update credits there is a potential for a race causing an
    overflow of vxcr_next (i.e. incrementing it past vxcr_ndesc). Change the
    check to >= rather than == to be more robust against this.
    
    Reviewed by:    emaste
    Sponsored by:   Rubicon Communications, LLC ("Netgate")
    Differential Revision:  https://reviews.freebsd.org/D43712
---
 sys/dev/vmware/vmxnet3/if_vmx.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sys/dev/vmware/vmxnet3/if_vmx.c b/sys/dev/vmware/vmxnet3/if_vmx.c
index fdcad0dd4bba..62b5f313a137 100644
--- a/sys/dev/vmware/vmxnet3/if_vmx.c
+++ b/sys/dev/vmware/vmxnet3/if_vmx.c
@@ -1429,7 +1429,8 @@ vmxnet3_isc_txd_credits_update(void *vsc, uint16_t txqid, bool clear)
 			return (1);
 		vmxnet3_barrier(sc, VMXNET3_BARRIER_RD);
 
-		if (++txc->vxcr_next == txc->vxcr_ndesc) {
+		MPASS(txc->vxcr_next < txc->vxcr_ndesc);
+		if (++txc->vxcr_next >= txc->vxcr_ndesc) {
 			txc->vxcr_next = 0;
 			txc->vxcr_gen ^= 1;
 		}