diff options
Diffstat (limited to 'net/mac80211/chan.c')
| -rw-r--r-- | net/mac80211/chan.c | 31 |
1 files changed, 29 insertions, 2 deletions
diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c index 5a7fb0e4f89d..6d0148dea126 100644 --- a/net/mac80211/chan.c +++ b/net/mac80211/chan.c @@ -547,8 +547,10 @@ static void ieee80211_change_chanctx(struct ieee80211_local *local, _ieee80211_change_chanctx(local, ctx, old_ctx, chanreq, NULL); } +/* Note: if successful, the returned chanctx is reserved for the link */ static struct ieee80211_chanctx * ieee80211_find_chanctx(struct ieee80211_local *local, + struct ieee80211_link_data *link, const struct ieee80211_chan_req *chanreq, enum ieee80211_chanctx_mode mode) { @@ -560,6 +562,9 @@ ieee80211_find_chanctx(struct ieee80211_local *local, if (mode == IEEE80211_CHANCTX_EXCLUSIVE) return NULL; + if (WARN_ON(link->reserved_chanctx)) + return NULL; + list_for_each_entry(ctx, &local->chanctx_list, list) { const struct ieee80211_chan_req *compat; @@ -578,6 +583,16 @@ ieee80211_find_chanctx(struct ieee80211_local *local, if (!compat) continue; + /* + * Reserve the chanctx temporarily, as the driver might change + * active links during callbacks we make into it below and/or + * later during assignment, which could (otherwise) cause the + * context to actually be removed. + */ + link->reserved_chanctx = ctx; + list_add(&link->reserved_chanctx_list, + &ctx->reserved_links); + ieee80211_change_chanctx(local, ctx, ctx, compat); return ctx; @@ -1701,6 +1716,7 @@ int ieee80211_link_use_channel(struct ieee80211_link_data *link, struct ieee80211_local *local = sdata->local; struct ieee80211_chanctx *ctx; u8 radar_detect_width = 0; + bool reserved = false; int ret; lockdep_assert_wiphy(local->hw.wiphy); @@ -1727,8 +1743,11 @@ int ieee80211_link_use_channel(struct ieee80211_link_data *link, __ieee80211_link_release_channel(link, false); - ctx = ieee80211_find_chanctx(local, chanreq, mode); - if (!ctx) + ctx = ieee80211_find_chanctx(local, link, chanreq, mode); + /* Note: context is now reserved */ + if (ctx) + reserved = true; + else ctx = ieee80211_new_chanctx(local, chanreq, mode); if (IS_ERR(ctx)) { ret = PTR_ERR(ctx); @@ -1738,6 +1757,14 @@ int ieee80211_link_use_channel(struct ieee80211_link_data *link, ieee80211_link_update_chanreq(link, chanreq); ret = ieee80211_assign_link_chanctx(link, ctx); + + if (reserved) { + /* remove reservation */ + WARN_ON(link->reserved_chanctx != ctx); + link->reserved_chanctx = NULL; + list_del(&link->reserved_chanctx_list); + } + if (ret) { /* if assign fails refcount stays the same */ if (ieee80211_chanctx_refcount(local, ctx) == 0) |