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authorJoe Eykholt <jeykholt@cisco.com>2010-03-12 16:08:55 -0800
committerJames Bottomley <James.Bottomley@suse.de>2010-04-11 09:23:44 -0500
commitf018b73af6db4f330ad5da9ac53997a699c30c42 (patch)
tree4f4e9405d923c0021771549dbdec34569c0e27a7 /drivers/scsi/libfc/fc_exch.c
parentb3ef990c1514859bffae221b9e82e46a38f1e7bf (diff)
[SCSI] libfc, libfcoe, fcoe: use smp_processor_id() only when preempt disabled
When the kernel is configured for preemption, using smp_processor_id() when preemption is enabled causes a warning backtrace and is wrong since we could move off of that CPU as soon as we get the ID, and we would be referencing the wrong CPU, and possibly an invalid one if it could be hotswapped out. Remove the fc_lport_get_stats() function and explicitly use per_cpu_ptr() to get the statistics. Where preemption has been disabled by holding a _bh lock continue to use smp_processor_id(), but otherwise use get_cpu()/put_cpu(). In fcoe_recv_frame() also changed the cases where we return in the middle to do a goto to the code which bumps ErrorFrames and does a put_cpu(). Two of these cases didn't bump ErrorFrames before, but doing so is harmless because they "can't happen", due to prior length checks. Also rearranged code in fcoe_recv_frame() to have only one call to fc_exch_recv(). It's just as efficient and saves a call to put_cpu(). In fc_fcp.c, adjusted a FIXME comment for code which doesn't need fixing. Signed-off-by: Joe Eykholt <jeykholt@cisco.com> Signed-off-by: Robert Love <robert.w.love@intel.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Diffstat (limited to 'drivers/scsi/libfc/fc_exch.c')
-rw-r--r--drivers/scsi/libfc/fc_exch.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c
index dc12a2bf0c9..d0496dafd84 100644
--- a/drivers/scsi/libfc/fc_exch.c
+++ b/drivers/scsi/libfc/fc_exch.c
@@ -676,9 +676,10 @@ static struct fc_exch *fc_exch_em_alloc(struct fc_lport *lport,
}
memset(ep, 0, sizeof(*ep));
- cpu = smp_processor_id();
+ cpu = get_cpu();
pool = per_cpu_ptr(mp->pool, cpu);
spin_lock_bh(&pool->lock);
+ put_cpu();
index = pool->next_index;
/* allocate new exch from pool */
while (fc_exch_ptr_get(pool, index)) {