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net: dsa: warn about dsa_port and dsa_switch bit fields being non atomic

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As discussed during review here:
https://patchwork.kernel.org/project/netdevbpf/patch/20220105132141.2648876-3-vladimir.oltean@nxp.com/

we should inform developers about pitfalls of concurrent access to the
boolean properties of dsa_switch and dsa_port, now that they've been
converted to bit fields. No other measure than a comment needs to be
taken, since the code paths that update these bit fields are not
concurrent with each other.

Suggested-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vladimir Oltean 2022-01-06 00:11:50 +02:00 committed by David S. Miller
parent 63cfc65753
commit 1b26d364e4
1 changed files with 8 additions and 0 deletions
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8
include/net/dsa.h
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@ -265,6 +265,10 @@ struct dsa_port {
u8 stp_state;
/* Warning: the following bit fields are not atomic, and updating them
* can only be done from code paths where concurrency is not possible
* (probe time or under rtnl_lock).
*/
u8 vlan_filtering:1;
/* Managed by DSA on user ports and by drivers on CPU and DSA ports */
@ -333,6 +337,10 @@ struct dsa_switch {
struct dsa_switch_tree *dst;
unsigned int index;
/* Warning: the following bit fields are not atomic, and updating them
* can only be done from code paths where concurrency is not possible
* (probe time or under rtnl_lock).
*/
u32 setup:1;
/* Disallow bridge core from requesting different VLAN awareness