This is v2 of a patch series that increases the maximum number of
IB HCAs supported per system.
The original mail thread is here:
http://lkml.org/lkml/2010/1/29/346
One note, I decided to "copy/paste" since factoring out the overflow
code in the three drivers seemed like overkill. If so desired, I could
factor those three separate functions into something provided by the
core, but that seemed like more trouble than it was worth at the time.
As before, I still don't have access to a giant system, so what I did
to test was to stick 4 cards into a small system, and then modify the
limits with debug patches similar to this:
diff --git a/drivers/infiniband/core/ucm.c b/drivers/infiniband/core/ucm.c
index 7bf0a82..8581e64 100644
--- a/drivers/infiniband/core/ucm.c
+++ b/drivers/infiniband/core/ucm.c
@@ -102,7 +102,7 @@ struct ib_ucm_event {
enum {
IB_UCM_MAJOR = 231,
IB_UCM_BASE_MINOR = 224,
- IB_UCM_MAX_DEVICES = 32
+ IB_UCM_MAX_DEVICES = 2
};
I tested all 3 drivers this way (uverbs, umad, ucm). I verified that
we're not leaking device numbers on multiple modprobe/rmmod cycles,
that there aren't any funny interactions when various combinations of
the drivers are loaded.
I did not test the rest of the OFED stack. I did write some trivial
programs to open the devices in /dev and close them again.
Here's an example of some of the testing:
dl585g2:~ # modprobe ib_uverbs
dl585g2:~ # modprobe ib_umad
dl585g2:~ # modprobe ib_ucm
dl585g2:~ # ls -l /dev/uverb*
crw-rw---- 1 root root 231, 192 Feb 2 05:55 /dev/uverbs0
crw-rw---- 1 root root 231, 193 Feb 2 05:55 /dev/uverbs1
crw-rw---- 1 root root 249, 0 Feb 2 05:55 /dev/uverbs2
crw-rw---- 1 root root 249, 1 Feb 2 05:55 /dev/uverbs3
dl585g2:~ # ls -l /dev/umad*
crw-rw---- 1 root root 231, 0 Feb 2 05:55 /dev/umad0
crw-rw---- 1 root root 231, 1 Feb 2 05:55 /dev/umad1
crw-rw---- 1 root root 231, 2 Feb 2 05:55 /dev/umad2
crw-rw---- 1 root root 231, 3 Feb 2 05:55 /dev/umad3
crw-rw---- 1 root root 248, 0 Feb 2 05:55 /dev/umad4
crw-rw---- 1 root root 248, 1 Feb 2 05:55 /dev/umad5
crw-rw---- 1 root root 248, 2 Feb 2 05:55 /dev/umad6
crw-rw---- 1 root root 248, 3 Feb 2 05:55 /dev/umad7
dl585g2:~ # ls -l /dev/issm*
crw-rw---- 1 root root 231, 4 Feb 2 05:55 /dev/issm0
crw-rw---- 1 root root 231, 5 Feb 2 05:55 /dev/issm1
crw-rw---- 1 root root 231, 6 Feb 2 05:55 /dev/issm2
crw-rw---- 1 root root 231, 7 Feb 2 05:55 /dev/issm3
crw-rw---- 1 root root 248, 4 Feb 2 05:55 /dev/issm4
crw-rw---- 1 root root 248, 5 Feb 2 05:55 /dev/issm5
crw-rw---- 1 root root 248, 6 Feb 2 05:55 /dev/issm6
crw-rw---- 1 root root 248, 7 Feb 2 05:55 /dev/issm7
dl585g2:~ # ls -l /dev/ucm*
crw-rw---- 1 root root 231, 224 Feb 2 05:55 /dev/ucm0
crw-rw---- 1 root root 231, 225 Feb 2 05:55 /dev/ucm1
crw-rw---- 1 root root 247, 0 Feb 2 05:55 /dev/ucm2
crw-rw---- 1 root root 247, 1 Feb 2 05:55 /dev/ucm3
Note that the major and minor numbers are behaving rather sanely.
dl585g2:~ # rmmod ib_ucm
dl585g2:~ # rmmod ib_uverbs
dl585g2:~ # rmmod ib_umad
Reset.
dl585g2:~ # modprobe ib_ucm
dl585g2:~ # ls -l /dev/ucm*
crw-rw---- 1 root root 231, 224 Feb 2 05:57 /dev/ucm0
crw-rw---- 1 root root 231, 225 Feb 2 05:57 /dev/ucm1
crw-rw---- 1 root root 248, 0 Feb 2 05:57 /dev/ucm2
crw-rw---- 1 root root 248, 1 Feb 2 05:57 /dev/ucm3
See that /dev/ucm* devices now have a different major number
compared to last time(248 vs 247), since we loaded that driver first.
But wait, why is it 248 and not 249? Is there a leak somewhere?
dl585g2:~ # ls -l /dev/uverb*
crw-rw---- 1 root root 231, 192 Feb 2 05:57 /dev/uverbs0
crw-rw---- 1 root root 231, 193 Feb 2 05:57 /dev/uverbs1
crw-rw---- 1 root root 249, 0 Feb 2 05:57 /dev/uverbs2
crw-rw---- 1 root root 249, 1 Feb 2 05:57 /dev/uverbs3
dl585g2:~ # rmmod ib_uverbs
ERROR: Module ib_uverbs is in use by ib_ucm
Ah, ib_ucm is dependent on ib_uverbs, so when we modprobed ib_ucm,
in reality ib_uverbs got loaded first. See how it has a higher
major number.
dl585g2:~ # rmmod ib_ucm
dl585g2:~ # rmmod ib_uverbs
dl585g2:~ # modprobe ib_umad
dl585g2:~ # ls -l /dev/umad*
crw-rw---- 1 root root 231, 0 Feb 2 05:58 /dev/umad0
crw-rw---- 1 root root 231, 1 Feb 2 05:58 /dev/umad1
crw-rw---- 1 root root 231, 2 Feb 2 05:58 /dev/umad2
crw-rw---- 1 root root 231, 3 Feb 2 05:58 /dev/umad3
crw-rw---- 1 root root 249, 0 Feb 2 05:58 /dev/umad4
crw-rw---- 1 root root 249, 1 Feb 2 05:58 /dev/umad5
crw-rw---- 1 root root 249, 2 Feb 2 05:58 /dev/umad6
crw-rw---- 1 root root 249, 3 Feb 2 05:58 /dev/umad7
dl585g2:~ # ls -l /dev/issm*
crw-rw---- 1 root root 231, 4 Feb 2 05:58 /dev/issm0
crw-rw---- 1 root root 231, 5 Feb 2 05:58 /dev/issm1
crw-rw---- 1 root root 231, 6 Feb 2 05:58 /dev/issm2
crw-rw---- 1 root root 231, 7 Feb 2 05:58 /dev/issm3
crw-rw---- 1 root root 249, 4 Feb 2 05:58 /dev/issm4
crw-rw---- 1 root root 249, 5 Feb 2 05:58 /dev/issm5
crw-rw---- 1 root root 249, 6 Feb 2 05:58 /dev/issm6
crw-rw---- 1 root root 249, 7 Feb 2 05:58 /dev/issm7
Finally, after one more reset, we see ib_umad loaded first and
obtaining the major number of 249.
v1 -> v2:
- update umad and ucm drivers too
---
Alex Chiang (18):
IB/uverbs: convert *cdev to cdev in struct ib_uverbs_device
IB/uverbs: remove dev_table
IB/uverbs: use stack variable 'devnum' in ib_uverbs_add_one
IB/uverbs: use stack variable 'base' in ib_uverbs_add_one
IB/uverbs: increase maximum devices supported
IB/uverbs: pack struct ib_uverbs_event_file tighter
IB/uverbs: whitespace cleanup
IB/umad: convert cdev pointers to embedded structs in struct ib_umad_port
IB/umad: remove port_table[]
IB/umad: use stack variable 'devnum' in ib_umad_init_port
IB/umad: use stack variable 'base' in ib_umad_init_port
IB/umad: increase maximum devices supported
IB/umad: clean whitespace
IB/ucm: use stack variable 'devnum' in ib_ucm_add_one
IB/ucm: use stack variable 'base' in ib_ucm_add_one
IB/ucm: increase maximum devices supported
IB/ucm: clean whitespace errors
IB/core: pack struct ib_device a little tighter
drivers/infiniband/core/ucm.c | 63 ++++++++++--
drivers/infiniband/core/user_mad.c | 173 +++++++++++++++++----------------
drivers/infiniband/core/uverbs.h | 11 +-
drivers/infiniband/core/uverbs_main.c | 175 +++++++++++++++++++--------------
include/rdma/ib_verbs.h | 4 -
5 files changed, 255 insertions(+), 171 deletions(-)
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