octeontx2-pf: Fix the use of GFP_KERNEL in atomic context on rt

commit 55ba18dc62deff5910c0fa64486dea1ff20832ff upstream.

The commit 4af1b64f80fb ("octeontx2-pf: Fix lmtst ID used in aura
free") uses the get/put_cpu() to protect the usage of percpu pointer
in ->aura_freeptr() callback, but it also unnecessarily disable the
preemption for the blockable memory allocation. The commit 87b93b678e95
("octeontx2-pf: Avoid use of GFP_KERNEL in atomic context") tried to
fix these sleep inside atomic warnings. But it only fix the one for
the non-rt kernel. For the rt kernel, we still get the similar warnings
like below.
  BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46
  in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper/0
  preempt_count: 1, expected: 0
  RCU nest depth: 0, expected: 0
  3 locks held by swapper/0/1:
   #0: ffff800009fc5fe8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x24/0x30
   #1: ffff000100c276c0 (&mbox->lock){+.+.}-{3:3}, at: otx2_init_hw_resources+0x8c/0x3a4
   #2: ffffffbfef6537e0 (&cpu_rcache->lock){+.+.}-{2:2}, at: alloc_iova_fast+0x1ac/0x2ac
  Preemption disabled at:
  [<ffff800008b1908c>] otx2_rq_aura_pool_init+0x14c/0x284
  CPU: 20 PID: 1 Comm: swapper/0 Tainted: G        W          6.2.0-rc3-rt1-yocto-preempt-rt #1
  Hardware name: Marvell OcteonTX CN96XX board (DT)
  Call trace:
   dump_backtrace.part.0+0xe8/0xf4
   show_stack+0x20/0x30
   dump_stack_lvl+0x9c/0xd8
   dump_stack+0x18/0x34
   __might_resched+0x188/0x224
   rt_spin_lock+0x64/0x110
   alloc_iova_fast+0x1ac/0x2ac
   iommu_dma_alloc_iova+0xd4/0x110
   __iommu_dma_map+0x80/0x144
   iommu_dma_map_page+0xe8/0x260
   dma_map_page_attrs+0xb4/0xc0
   __otx2_alloc_rbuf+0x90/0x150
   otx2_rq_aura_pool_init+0x1c8/0x284
   otx2_init_hw_resources+0xe4/0x3a4
   otx2_open+0xf0/0x610
   __dev_open+0x104/0x224
   __dev_change_flags+0x1e4/0x274
   dev_change_flags+0x2c/0x7c
   ic_open_devs+0x124/0x2f8
   ip_auto_config+0x180/0x42c
   do_one_initcall+0x90/0x4dc
   do_basic_setup+0x10c/0x14c
   kernel_init_freeable+0x10c/0x13c
   kernel_init+0x2c/0x140
   ret_from_fork+0x10/0x20

Of course, we can shuffle the get/put_cpu() to only wrap the invocation
of ->aura_freeptr() as what commit 87b93b678e95 does. But there are only
two ->aura_freeptr() callbacks, otx2_aura_freeptr() and
cn10k_aura_freeptr(). There is no usage of perpcu variable in the
otx2_aura_freeptr() at all, so the get/put_cpu() seems redundant to it.
We can move the get/put_cpu() into the corresponding callback which
really has the percpu variable usage and avoid the sprinkling of
get/put_cpu() in several places.

Fixes: 4af1b64f80fb ("octeontx2-pf: Fix lmtst ID used in aura free")
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Link: https://lore.kernel.org/r/20230118071300.3271125-1-haokexin@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
index 497b777..8a41ad8 100644 (file)
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
@@ -1012,7 +1012,6 @@ static void otx2_pool_refill_task(struct work_struct *work)
        rbpool = cq->rbpool;
        free_ptrs = cq->pool_ptrs;
 
-       get_cpu();
        while (cq->pool_ptrs) {
                if (otx2_alloc_rbuf(pfvf, rbpool, &bufptr)) {
                        /* Schedule a WQ if we fails to free atleast half of the
@@ -1032,7 +1031,6 @@ static void otx2_pool_refill_task(struct work_struct *work)
                pfvf->hw_ops->aura_freeptr(pfvf, qidx, bufptr + OTX2_HEAD_ROOM);
                cq->pool_ptrs--;
        }
-       put_cpu();
        cq->refill_task_sched = false;
 }
 
@@ -1387,9 +1385,7 @@ int otx2_sq_aura_pool_init(struct otx2_nic *pfvf)
                        err = otx2_alloc_rbuf(pfvf, pool, &bufptr);
                        if (err)
                                goto err_mem;
-                       get_cpu();
                        pfvf->hw_ops->aura_freeptr(pfvf, pool_id, bufptr);
-                       put_cpu();
                        sq->sqb_ptrs[sq->sqb_count++] = (u64)bufptr;
                }
        }
@@ -1435,21 +1431,18 @@ int otx2_rq_aura_pool_init(struct otx2_nic *pfvf)
        if (err)
                goto fail;
 
-       get_cpu();
        /* Allocate pointers and free them to aura/pool */
        for (pool_id = 0; pool_id < hw->rqpool_cnt; pool_id++) {
                pool = &pfvf->qset.pool[pool_id];
                for (ptr = 0; ptr < num_ptrs; ptr++) {
                        err = otx2_alloc_rbuf(pfvf, pool, &bufptr);
                        if (err)
-                               goto err_mem;
+                               return -ENOMEM;
                        pfvf->hw_ops->aura_freeptr(pfvf, pool_id,
                                                   bufptr + OTX2_HEAD_ROOM);
                }
        }
-err_mem:
-       put_cpu();
-       return err ? -ENOMEM : 0;
+       return 0;
 fail:
        otx2_mbox_reset(&pfvf->mbox.mbox, 0);
        otx2_aura_pool_free(pfvf);

diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h
index 67aa02b..712715a 100644 (file)
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h
@@ -733,8 +733,10 @@ static inline void cn10k_aura_freeptr(void *dev, int aura, u64 buf)
        u64 ptrs[2];
 
        ptrs[1] = buf;
+       get_cpu();
        /* Free only one buffer at time during init and teardown */
        __cn10k_aura_freeptr(pfvf, aura, ptrs, 2);
+       put_cpu();
 }
 
 /* Alloc pointer from pool/aura */