[net-next PATCH v2] octeontx2-af: Fix multicast/mirror group lock/unlock issue

Suman Ghosh
2023-12-13T09:54:23Z

As per the existing implementation, there exists a race between finding
a multicast/mirror group entry and deleting that entry. The group lock
was taken and released independently by rvu_nix_mcast_find_grp_elem()
function. Which is incorrect and group lock should be taken during the
entire operation of group updation/deletion. This patch fixes the same.

Fixes: 51b2804c19cd ("octeontx2-af: Add new mbox to support multicast/mirror offload")
Signed-off-by: Suman Ghosh <sumang@marvell.com>
---
Note: This is a follow up of

https://urldefense.proofpoint.com/v2/url?u=https-3A__git.kernel.org_netdev_net-2Dnext_c_51b2804c19cd&d=DwIDaQ&c=nKjWec2b6R0mOyPaz7xtfQ&r=7si3Xn9Ly-Se1a655kvEPIYU0nQ9HPeN280sEUv5ROU&m=NjKPoTkYVlL5Dh4aSr3-dVo-AukiIperlvB0S4_Mqzkyl_VcYAAKrWhkGZE5Cx-p&s=AkBf0454Xm-0adqV0Os7ZE8peaCXtYyuNbCS5kit6Jk&e=

v2 changes:
- Addresed review comments from Simon about a missed unlock and re-org the code
with some goto labels.

.../ethernet/marvell/octeontx2/af/rvu_nix.c | 84 ++++++++++++-------
1 file changed, 54 insertions(+), 30 deletions(-)

diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
index b01503acd520..72e0a7717c3e 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c
@@ -6142,14 +6142,12 @@ static struct nix_mcast_grp_elem *rvu_nix_mcast_find_grp_elem(struct nix_mcast_g
struct nix_mcast_grp_elem *iter;
bool is_found = false;

- mutex_lock(&mcast_grp->mcast_grp_lock);
list_for_each_entry(iter, &mcast_grp->mcast_grp_head, list) {
if (iter->mcast_grp_idx == mcast_grp_idx) {
is_found = true;
break;
}
}
- mutex_unlock(&mcast_grp->mcast_grp_lock);

if (is_found)
return iter;
@@ -6162,7 +6160,7 @@ int rvu_nix_mcast_get_mce_index(struct rvu *rvu, u16 pcifunc, u32 mcast_grp_idx)
struct nix_mcast_grp_elem *elem;
struct nix_mcast_grp *mcast_grp;
struct nix_hw *nix_hw;
- int blkaddr;
+ int blkaddr, ret;

blkaddr = rvu_get_blkaddr(rvu, BLKTYPE_NIX, pcifunc);
nix_hw = get_nix_hw(rvu->hw, blkaddr);
@@ -6170,11 +6168,15 @@ int rvu_nix_mcast_get_mce_index(struct rvu *rvu, u16 pcifunc, u32 mcast_grp_idx)
return NIX_AF_ERR_INVALID_NIXBLK;

mcast_grp = &nix_hw->mcast_grp;
+ mutex_lock(&mcast_grp->mcast_grp_lock);
elem = rvu_nix_mcast_find_grp_elem(mcast_grp, mcast_grp_idx);
if (!elem)
- return NIX_AF_ERR_INVALID_MCAST_GRP;
+ ret = NIX_AF_ERR_INVALID_MCAST_GRP;
+ else
+ ret = elem->mce_start_index;

- return elem->mce_start_index;
+ mutex_unlock(&mcast_grp->mcast_grp_lock);
+ return ret;
}

void rvu_nix_mcast_flr_free_entries(struct rvu *rvu, u16 pcifunc)
@@ -6238,7 +6240,7 @@ int rvu_nix_mcast_update_mcam_entry(struct rvu *rvu, u16 pcifunc,
struct nix_mcast_grp_elem *elem;
struct nix_mcast_grp *mcast_grp;
struct nix_hw *nix_hw;
- int blkaddr;
+ int blkaddr, ret = 0;

blkaddr = rvu_get_blkaddr(rvu, BLKTYPE_NIX, pcifunc);
nix_hw = get_nix_hw(rvu->hw, blkaddr);
@@ -6246,13 +6248,15 @@ int rvu_nix_mcast_update_mcam_entry(struct rvu *rvu, u16 pcifunc,
return NIX_AF_ERR_INVALID_NIXBLK;

mcast_grp = &nix_hw->mcast_grp;
+ mutex_lock(&mcast_grp->mcast_grp_lock);
elem = rvu_nix_mcast_find_grp_elem(mcast_grp, mcast_grp_idx);
if (!elem)
- return NIX_AF_ERR_INVALID_MCAST_GRP;
-
- elem->mcam_index = mcam_index;
+ ret = NIX_AF_ERR_INVALID_MCAST_GRP;
+ else
+ elem->mcam_index = mcam_index;

- return 0;
+ mutex_unlock(&mcast_grp->mcast_grp_lock);
+ return ret;
}

int rvu_mbox_handler_nix_mcast_grp_create(struct rvu *rvu,
@@ -6297,18 +6301,27 @@ int rvu_mbox_handler_nix_mcast_grp_destroy(struct rvu *rvu,
struct npc_delete_flow_rsp uninstall_rsp = { 0 };
struct nix_mcast_grp_elem *elem;
struct nix_mcast_grp *mcast_grp;
+ int blkaddr, err, ret = 0;
struct nix_mcast *mcast;
struct nix_hw *nix_hw;
- int blkaddr, err;

err = nix_get_struct_ptrs(rvu, req->hdr.pcifunc, &nix_hw, &blkaddr);
if (err)
return err;

mcast_grp = &nix_hw->mcast_grp;
+
+ /* If AF is requesting for the deletion,
+ * then AF is already taking the lock
+ */
+ if (!req->is_af)
+ mutex_lock(&mcast_grp->mcast_grp_lock);
+
elem = rvu_nix_mcast_find_grp_elem(mcast_grp, req->mcast_grp_idx);
- if (!elem)
- return NIX_AF_ERR_INVALID_MCAST_GRP;
+ if (!elem) {
+ ret = NIX_AF_ERR_INVALID_MCAST_GRP;
+ goto unlock_grp;
+ }

/* If no mce entries are associated with the group
* then just remove it from the global list.
@@ -6333,19 +6346,15 @@ int rvu_mbox_handler_nix_mcast_grp_destroy(struct rvu *rvu,
mutex_unlock(&mcast->mce_lock);

delete_grp:
- /* If AF is requesting for the deletion,
- * then AF is already taking the lock
- */
- if (!req->is_af)
- mutex_lock(&mcast_grp->mcast_grp_lock);
-
list_del(&elem->list);
kfree(elem);
mcast_grp->count--;
+
+unlock_grp:
if (!req->is_af)
mutex_unlock(&mcast_grp->mcast_grp_lock);

- return 0;
+ return ret;
}

int rvu_mbox_handler_nix_mcast_grp_update(struct rvu *rvu,
@@ -6370,9 +6379,18 @@ int rvu_mbox_handler_nix_mcast_grp_update(struct rvu *rvu,
return err;

mcast_grp = &nix_hw->mcast_grp;
+
+ /* If AF is requesting for the updation,
+ * then AF is already taking the lock
+ */
+ if (!req->is_af)
+ mutex_lock(&mcast_grp->mcast_grp_lock);
+
elem = rvu_nix_mcast_find_grp_elem(mcast_grp, req->mcast_grp_idx);
- if (!elem)
- return NIX_AF_ERR_INVALID_MCAST_GRP;
+ if (!elem) {
+ ret = NIX_AF_ERR_INVALID_MCAST_GRP;
+ goto unlock_grp;
+ }

/* If any pcifunc matches the group's pcifunc, then we can
* delete the entire group.
@@ -6383,9 +6401,10 @@ int rvu_mbox_handler_nix_mcast_grp_update(struct rvu *rvu,
/* Delete group */
dreq.hdr.pcifunc = elem->pcifunc;
dreq.mcast_grp_idx = elem->mcast_grp_idx;
- dreq.is_af = req->is_af;
+ dreq.is_af = 1;
rvu_mbox_handler_nix_mcast_grp_destroy(rvu, &dreq, NULL);
- return 0;
+ ret = 0;
+ goto unlock_grp;
}
}
}
@@ -6410,7 +6429,7 @@ int rvu_mbox_handler_nix_mcast_grp_update(struct rvu *rvu,
npc_enable_mcam_entry(rvu, mcam, npc_blkaddr,
elem->mcam_index, true);
ret = NIX_AF_ERR_NON_CONTIG_MCE_LIST;
- goto done;
+ goto unlock_mce;
}
}

@@ -6426,7 +6445,7 @@ int rvu_mbox_handler_nix_mcast_grp_update(struct rvu *rvu,
npc_enable_mcam_entry(rvu, mcam, npc_blkaddr,
elem->mcam_index, true);

- goto done;
+ goto unlock_mce;
}
} else {
if (!prev_count || prev_count < req->num_mce_entry) {
@@ -6434,7 +6453,7 @@ int rvu_mbox_handler_nix_mcast_grp_update(struct rvu *rvu,
npc_enable_mcam_entry(rvu, mcam, npc_blkaddr,
elem->mcam_index, true);
ret = NIX_AF_ERR_INVALID_MCAST_DEL_REQ;
- goto done;
+ goto unlock_mce;
}

nix_free_mce_list(mcast, prev_count, elem->mce_start_index, elem->dir);
@@ -6450,14 +6469,14 @@ int rvu_mbox_handler_nix_mcast_grp_update(struct rvu *rvu,
elem->mcam_index,
true);

- goto done;
+ goto unlock_mce;
}
}

if (elem->mcam_index == -1) {
rsp->mce_start_index = elem->mce_start_index;
ret = 0;
- goto done;
+ goto unlock_mce;
}

nix_mcast_update_action(rvu, elem);
@@ -6465,7 +6484,12 @@ int rvu_mbox_handler_nix_mcast_grp_update(struct rvu *rvu,
rsp->mce_start_index = elem->mce_start_index;
ret = 0;

-done:
+unlock_mce:
mutex_unlock(&mcast->mce_lock);
+
+unlock_grp:
+ if (!req->is_af)
+ mutex_unlock(&mcast_grp->mcast_grp_lock);
+
return ret;
}
--
2.25.1