linux-toradex.git/net/mac80211/mesh_pathtbl.c, branch v4.10 Linux kernel for Apalis and Colibri modules mac80211: make mpath path fixing more robust 2016-09-12T10:27:14+00:00 Pedersen, Thomas twp@qca.qualcomm.com 2016-09-06T18:59:00+00:00 5df20f2141eadb5430caaad20eceac61cfe0f139 A fixed mpath was not quite being treated as such: 1) if a PERR frame was received, a fixed mpath was deactivated. 2) queued path discovery for fixed mpath was potentially being considered, changing mpath state. 3) other mpath flags were potentially being inherited when fixing the mpath. Just assign PATH_FIXED and SN_VALID. This solves several issues when fixing a mesh path in one direction. The reverse direction mpath should probably also be fixed, or root announcements at least be enabled. Signed-off-by: Thomas Pedersen <twp@qca.qualcomm.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> 
A fixed mpath was not quite being treated as such:

1) if a PERR frame was received, a fixed mpath was
   deactivated.

2) queued path discovery for fixed mpath was potentially
   being considered, changing mpath state.

3) other mpath flags were potentially being inherited when
   fixing the mpath. Just assign PATH_FIXED and SN_VALID.

This solves several issues when fixing a mesh path in one
direction. The reverse direction mpath should probably
also be fixed, or root announcements at least be enabled.

Signed-off-by: Thomas Pedersen <twp@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
mac80211: mesh: embed gates hlist head directly 2016-04-05T19:34:51+00:00 Bob Copeland me@bobcopeland.com 2016-03-19T02:11:30+00:00 18b27ff7d2e232b0f07f2f51aa8052ff2a617908 Since we have converted the mesh path tables to rhashtable, we are no longer swapping out the entire mesh_pathtbl pointer with RCU. As a result, we no longer need indirection to the hlist head for the gates list and can simply embed it, saving a pair of pointer-sized allocations. Signed-off-by: Bob Copeland <me@bobcopeland.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> 
Since we have converted the mesh path tables to rhashtable, we are
no longer swapping out the entire mesh_pathtbl pointer with RCU.
As a result, we no longer need indirection to the hlist head for
the gates list and can simply embed it, saving a pair of
pointer-sized allocations.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
mac80211: mesh: fix crash in mesh_path_timer 2016-04-05T19:34:49+00:00 Bob Copeland me@bobcopeland.com 2016-03-19T02:03:24+00:00 749329594b5e0fb612b2de642a692323ddf661dd The mesh_path_reclaim() function, called from an rcu callback, cancels the mesh_path_timer associated with a mesh path. Unfortunately, this call can happen much later, perhaps after the hash table itself is destroyed. Such a situation led to the following crash in mesh_path_send_to_gates() when dereferencing the tbl pointer: [ 23.901661] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 [ 23.905516] IP: [<ffffffff814c910b>] mesh_path_send_to_gates+0x2b/0x740 [ 23.908757] PGD 99ca067 PUD 99c4067 PMD 0 [ 23.910789] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC [ 23.913485] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.5.0-rc6-wt+ #43 [ 23.916675] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 [ 23.920471] task: ffffffff81685500 ti: ffffffff81678000 task.ti: ffffffff81678000 [ 23.922619] RIP: 0010:[<ffffffff814c910b>] [<ffffffff814c910b>] mesh_path_send_to_gates+0x2b/0x740 [ 23.925237] RSP: 0018:ffff88000b403d30 EFLAGS: 00010286 [ 23.926739] RAX: 0000000000000000 RBX: ffff880009bc0d20 RCX: 0000000000000102 [ 23.928796] RDX: 000000000000002e RSI: 0000000000000001 RDI: ffff880009bc0d20 [ 23.930895] RBP: ffff88000b403e18 R08: 0000000000000001 R09: 0000000000000001 [ 23.932917] R10: 0000000000000000 R11: 0000000000000001 R12: ffff880009c20940 [ 23.936370] R13: ffff880009bc0e70 R14: ffff880009c21c40 R15: ffff880009bc0d20 [ 23.939823] FS: 0000000000000000(0000) GS:ffff88000b400000(0000) knlGS:0000000000000000 [ 23.943688] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 23.946429] CR2: 0000000000000008 CR3: 00000000099c5000 CR4: 00000000000006b0 [ 23.949861] Stack: [ 23.950840] 000000000000002e ffff880009c20940 ffff88000b403da8 ffffffff8109e551 [ 23.954467] ffffffff82711be2 000000000000002e 0000000000000000 ffffffff8166a5f5 [ 23.958141] 0000000000685ce8 0000000000000246 ffff880009bc0d20 ffff880009c20940 [ 23.961801] Call Trace: [ 23.962987] <IRQ> [ 23.963963] [<ffffffff8109e551>] ? vprintk_emit+0x351/0x5e0 [ 23.966782] [<ffffffff8109e8ff>] ? vprintk_default+0x1f/0x30 [ 23.969529] [<ffffffff810ffa41>] ? printk+0x48/0x50 [ 23.971956] [<ffffffff814ceef3>] mesh_path_timer+0x133/0x160 [ 23.974707] [<ffffffff814cedc0>] ? mesh_nexthop_resolve+0x230/0x230 [ 23.977775] [<ffffffff810b04ee>] call_timer_fn+0xce/0x330 [ 23.980448] [<ffffffff810b0425>] ? call_timer_fn+0x5/0x330 [ 23.983126] [<ffffffff814cedc0>] ? mesh_nexthop_resolve+0x230/0x230 [ 23.986091] [<ffffffff810b097c>] run_timer_softirq+0x22c/0x390 Instead of cancelling in the RCU callback, set a new flag to prevent the timer from being rearmed, and then cancel the timer synchronously when freeing the mesh path. This leaves mesh_path_reclaim() doing nothing but kfree, so switch to kfree_rcu(). Fixes: 3b302ada7f0a ("mac80211: mesh: move path tables into if_mesh") Signed-off-by: Bob Copeland <me@bobcopeland.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> 
The mesh_path_reclaim() function, called from an rcu callback, cancels
the mesh_path_timer associated with a mesh path.  Unfortunately, this
call can happen much later, perhaps after the hash table itself is
destroyed.

Such a situation led to the following crash in mesh_path_send_to_gates()
when dereferencing the tbl pointer:

[   23.901661] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
[   23.905516] IP: [<ffffffff814c910b>] mesh_path_send_to_gates+0x2b/0x740
[   23.908757] PGD 99ca067 PUD 99c4067 PMD 0
[   23.910789] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[   23.913485] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.5.0-rc6-wt+ #43
[   23.916675] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
[   23.920471] task: ffffffff81685500 ti: ffffffff81678000 task.ti: ffffffff81678000
[   23.922619] RIP: 0010:[<ffffffff814c910b>]  [<ffffffff814c910b>] mesh_path_send_to_gates+0x2b/0x740
[   23.925237] RSP: 0018:ffff88000b403d30  EFLAGS: 00010286
[   23.926739] RAX: 0000000000000000 RBX: ffff880009bc0d20 RCX: 0000000000000102
[   23.928796] RDX: 000000000000002e RSI: 0000000000000001 RDI: ffff880009bc0d20
[   23.930895] RBP: ffff88000b403e18 R08: 0000000000000001 R09: 0000000000000001
[   23.932917] R10: 0000000000000000 R11: 0000000000000001 R12: ffff880009c20940
[   23.936370] R13: ffff880009bc0e70 R14: ffff880009c21c40 R15: ffff880009bc0d20
[   23.939823] FS:  0000000000000000(0000) GS:ffff88000b400000(0000) knlGS:0000000000000000
[   23.943688] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[   23.946429] CR2: 0000000000000008 CR3: 00000000099c5000 CR4: 00000000000006b0
[   23.949861] Stack:
[   23.950840]  000000000000002e ffff880009c20940 ffff88000b403da8 ffffffff8109e551
[   23.954467]  ffffffff82711be2 000000000000002e 0000000000000000 ffffffff8166a5f5
[   23.958141]  0000000000685ce8 0000000000000246 ffff880009bc0d20 ffff880009c20940
[   23.961801] Call Trace:
[   23.962987]  <IRQ>
[   23.963963]  [<ffffffff8109e551>] ? vprintk_emit+0x351/0x5e0
[   23.966782]  [<ffffffff8109e8ff>] ? vprintk_default+0x1f/0x30
[   23.969529]  [<ffffffff810ffa41>] ? printk+0x48/0x50
[   23.971956]  [<ffffffff814ceef3>] mesh_path_timer+0x133/0x160
[   23.974707]  [<ffffffff814cedc0>] ? mesh_nexthop_resolve+0x230/0x230
[   23.977775]  [<ffffffff810b04ee>] call_timer_fn+0xce/0x330
[   23.980448]  [<ffffffff810b0425>] ? call_timer_fn+0x5/0x330
[   23.983126]  [<ffffffff814cedc0>] ? mesh_nexthop_resolve+0x230/0x230
[   23.986091]  [<ffffffff810b097c>] run_timer_softirq+0x22c/0x390

Instead of cancelling in the RCU callback, set a new flag to prevent the
timer from being rearmed, and then cancel the timer synchronously when
freeing the mesh path.  This leaves mesh_path_reclaim() doing nothing
but kfree, so switch to kfree_rcu().

Fixes: 3b302ada7f0a ("mac80211: mesh: move path tables into if_mesh")
Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
mac80211: mesh: convert path table to rhashtable 2016-04-05T08:56:33+00:00 Bob Copeland me@bobcopeland.com 2016-03-02T15:09:20+00:00 60854fd94573f0d3b80b55b40cf0140a0430f3ab In the time since the mesh path table was implemented as an RCU-traversable, dynamically growing hash table, a generic RCU hashtable implementation was added to the kernel. Switch the mesh path table over to rhashtable to remove some code and also gain some features like automatic shrinking. Cc: Thomas Graf <tgraf@suug.ch> Cc: netdev@vger.kernel.org Signed-off-by: Bob Copeland <me@bobcopeland.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> 
In the time since the mesh path table was implemented as an
RCU-traversable, dynamically growing hash table, a generic RCU
hashtable implementation was added to the kernel.

Switch the mesh path table over to rhashtable to remove some code
and also gain some features like automatic shrinking.

Cc: Thomas Graf <tgraf@suug.ch>
Cc: netdev@vger.kernel.org
Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
mac80211: mesh: embed known gates list in struct mesh_path 2016-04-05T08:56:32+00:00 Bob Copeland me@bobcopeland.com 2016-02-29T01:03:59+00:00 947c2a0eccec29fcd30e717787e65792b1e607ed The mesh path table uses a struct mesh_node in its hlists in order to support a resizable hash table: the mesh_node provides an indirection to the actual mesh path so that two different bucket lists can point to the same path entry. However, for the known gates list, we don't need this indirection because there is ever only one list. So we can just embed the hlist_node in the mesh path itself, which simplifies things a bit and saves a linear search whenever we need to find an item in the list. Signed-off-by: Bob Copeland <me@bobcopeland.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> 
The mesh path table uses a struct mesh_node in its hlists in
order to support a resizable hash table: the mesh_node provides
an indirection to the actual mesh path so that two different
bucket lists can point to the same path entry.

However, for the known gates list, we don't need this indirection
because there is ever only one list.  So we can just embed the
hlist_node in the mesh path itself, which simplifies things a bit
and saves a linear search whenever we need to find an item in
the list.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
mac80211: mesh: factor out common mesh path allocation code 2016-04-05T08:56:31+00:00 Bob Copeland me@bobcopeland.com 2016-02-29T01:03:58+00:00 b15dc38b9817729d3d4962f8c84bbda0eccb3532 Remove duplicate code to allocate and initialize a mesh path or mesh proxy path. Signed-off-by: Bob Copeland <me@bobcopeland.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> 
Remove duplicate code to allocate and initialize a mesh
path or mesh proxy path.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
mac80211: mesh: don't hash sdata in mpath tables 2016-04-05T08:56:31+00:00 Bob Copeland me@bobcopeland.com 2016-02-29T01:03:57+00:00 443954815b63b36f09623d74170520e6554f5fac Now that the sdata pointer is the same for all entries of a path table, hashing it is pointless, so hash only the address. Signed-off-by: Bob Copeland <me@bobcopeland.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> 
Now that the sdata pointer is the same for all entries of a
path table, hashing it is pointless, so hash only the address.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
mac80211: mesh: move path tables into if_mesh 2016-04-05T08:56:30+00:00 Bob Copeland me@bobcopeland.com 2016-02-29T01:03:56+00:00 2bdaf386f99c4a82788812e583ff59c6714ae4d6 The mesh path and mesh gate hashtables are global, containing all of the mpaths for every mesh interface, but the paths are all tied logically to a single interface. The common case is just a single mesh interface, so optimize for that by moving the global hashtable into the per-interface struct. Doing so allows us to drop sdata pointer comparisons inside the lookups and also saves a few bytes of BSS and data. Signed-off-by: Bob Copeland <me@bobcopeland.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> 
The mesh path and mesh gate hashtables are global, containing
all of the mpaths for every mesh interface, but the paths are
all tied logically to a single interface.  The common case is
just a single mesh interface, so optimize for that by moving
the global hashtable into the per-interface struct.

Doing so allows us to drop sdata pointer comparisons inside
the lookups and also saves a few bytes of BSS and data.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
mac80211: Unify mesh and mpp path removal function 2016-02-24T08:04:36+00:00 Henning Rogge hrogge@gmail.com 2016-02-03T12:58:38+00:00 4cc955de7c99fe60b09688d7c2564f8fc7d00ca2 mpp_path_del() and mesh_path_del() are mostly the same function. Move common code into a new static function. Acked-by: Bob Copeland <me@bobcopeland.com> Signed-off-by: Henning Rogge <henning.rogge@fkie.fraunhofer.de> Signed-off-by: Johannes Berg <johannes.berg@intel.com> 
mpp_path_del() and mesh_path_del() are mostly the same function.
Move common code into a new static function.

Acked-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Henning Rogge <henning.rogge@fkie.fraunhofer.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
mac80211: let unused MPP table entries timeout 2016-02-24T08:04:35+00:00 Henning Rogge hrogge@gmail.com 2016-02-03T12:58:37+00:00 ab1c7906b0bead549065a3a2def5aeda21818c99 Remember the last time when a mpp table entry is used for rx or tx and remove them after MESH_PATH_EXPIRE time. Acked-by: Bob Copeland <me@bobcopeland.com> Signed-off-by: Henning Rogge <henning.rogge@fkie.fraunhofer.de> Signed-off-by: Johannes Berg <johannes.berg@intel.com> 
Remember the last time when a mpp table entry is used for
rx or tx and remove them after MESH_PATH_EXPIRE time.

Acked-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Henning Rogge <henning.rogge@fkie.fraunhofer.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>