[PATCH net v2] octeontx2-af: Fix BPID leak in nix_bp_enable()

[<nshettyj@marvell.com>]

From: Rakesh Kudurumalla <rkudurumalla@marvell.com>

For LBK interfaces, rvu_nix_get_bpid() allocates a BPID from the free
pool on every call. nix_bp_enable() called it unconditionally before
the loop, and again after the last channel was programmed, leaking a
BPID whenever that extra call's result went unused. With
req->chan_cnt == 0, the pre-loop call leaked a BPID on every call.

Move the allocation into the loop body so it runs exactly once per
channel actually programmed, and reject req->chan_cnt == 0 upfront.

Fixes: d6212d2e41a0 ("octeontx2-af: Create BPIDs free pool")
Signed-off-by: Nitin Shetty J <nshettyj@marvell.com>
Signed-off-by: Rakesh Kudurumalla <rkudurumalla@marvell.com>
---
changes in v2:
- Move the rvu_nix_get_bpid() call for LBK BPID allocation from before
  the loop into the loop body.
- Validate req->chan_cnt before allocating BPIDs.
- updated commit message and fix tag
---
 drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
index 153eb57bad06..3a43432d29c1 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
@@ -764,19 +764,25 @@ static int nix_bp_enable(struct rvu *rvu,
 	if (cpt_link && !rvu->hw->cpt_links)
 		return 0;
 
+	if (!req->chan_cnt)
+		return NIX_AF_ERR_INVALID_BPID_REQ;
+
 	pfvf = rvu_get_pfvf(rvu, pcifunc);
 	blkaddr = rvu_get_blkaddr(rvu, BLKTYPE_NIX, pcifunc);
 
-	bpid_base = rvu_nix_get_bpid(rvu, req, type, chan_id);
 	chan_base = pfvf->rx_chan_base + req->chan_base;
-	bpid = bpid_base;
+	bpid_base = -1;
 
 	for (chan = chan_base; chan < (chan_base + req->chan_cnt); chan++) {
+		bpid = rvu_nix_get_bpid(rvu, req, type, chan_id);
 		if (bpid < 0) {
 			dev_warn(rvu->dev, "Fail to enable backpressure\n");
 			return -EINVAL;
 		}
 
+		if (bpid_base < 0)
+			bpid_base = bpid;
+
 		chan_v = nix_get_channel(chan, cpt_link);
 
 		cfg = rvu_read64(rvu, blkaddr, NIX_AF_RX_CHANX_CFG(chan_v));
@@ -784,7 +790,6 @@ static int nix_bp_enable(struct rvu *rvu,
 		rvu_write64(rvu, blkaddr, NIX_AF_RX_CHANX_CFG(chan_v),
 			    cfg | (bpid & GENMASK_ULL(8, 0)) | BIT_ULL(16));
 		chan_id++;
-		bpid = rvu_nix_get_bpid(rvu, req, type, chan_id);
 	}
 
 	for (chan = 0; chan < req->chan_cnt; chan++) {
-- 
2.48.1