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authorJohannes Berg <johannes.berg@intel.com>2021-01-22 18:19:43 +0300
committerJohannes Berg <johannes.berg@intel.com>2021-01-26 13:55:50 +0300
commita05829a7222e9d10c416dd2dbbf3929fe6646b89 (patch)
tree87d6d74e56da555ca3976d42fa94589f917b23ce /net/wireless/debugfs.c
parent2fe8ef106238b274c505c480ecf00d8765abf0d8 (diff)
downloadlinux-a05829a7222e9d10c416dd2dbbf3929fe6646b89.tar.xz
cfg80211: avoid holding the RTNL when calling the driver
Currently, _everything_ in cfg80211 holds the RTNL, and if you have a slow USB device (or a few) you can get some bad lock contention on that. Fix that by re-adding a mutex to each wiphy/rdev as we had at some point, so we have locking for the wireless_dev lists and all the other things in there, and also so that drivers still don't have to worry too much about it (they still won't get parallel calls for a single device). Then, we can restrict the RTNL to a few cases where we add or remove interfaces and really need the added protection. Some of the global list management still also uses the RTNL, since we need to have it anyway for netdev management, but we only hold the RTNL for very short periods of time here. Link: https://lore.kernel.org/r/20210122161942.81df9f5e047a.I4a8e1a60b18863ea8c5e6d3a0faeafb2d45b2f40@changeid Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> [marvell driver issues] Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/wireless/debugfs.c')
-rw-r--r--net/wireless/debugfs.c4
1 files changed, 0 insertions, 4 deletions
diff --git a/net/wireless/debugfs.c b/net/wireless/debugfs.c
index 76b845f68ac8..aab43469a2f0 100644
--- a/net/wireless/debugfs.c
+++ b/net/wireless/debugfs.c
@@ -73,8 +73,6 @@ static ssize_t ht40allow_map_read(struct file *file,
if (!buf)
return -ENOMEM;
- rtnl_lock();
-
for (band = 0; band < NUM_NL80211_BANDS; band++) {
sband = wiphy->bands[band];
if (!sband)
@@ -84,8 +82,6 @@ static ssize_t ht40allow_map_read(struct file *file,
buf, buf_size, offset);
}
- rtnl_unlock();
-
r = simple_read_from_buffer(user_buf, count, ppos, buf, offset);
kfree(buf);