[PATCH 00/39] drop null test before destroy functions

[PATCH 00/39] drop null test before destroy functions

[Julia Lawall]

Recent commits to kernel/git/torvalds/linux.git have made the following
functions able to tolerate NULL arguments:

kmem_cache_destroy (commit 3942d29918522)
mempool_destroy (commit 4e3ca3e033d1)
dma_pool_destroy (commit 44d7175da6ea)

These patches remove the associated NULL tests for the files that I found
easy to compile test.  If these changes are OK, I will address the
remainder later.

---

 arch/x86/kvm/mmu.c                                 |    6 --
 block/bio-integrity.c                              |    7 --
 block/bio.c                                        |    7 --
 block/blk-core.c                                   |    3 -
 block/elevator.c                                   |    3 -
 drivers/atm/he.c                                   |    7 --
 drivers/block/aoe/aoedev.c                         |    3 -
 drivers/block/drbd/drbd_main.c                     |   21 ++-----
 drivers/block/pktcdvd.c                            |    3 -
 drivers/block/rbd.c                                |    6 --
 drivers/dma/dmaengine.c                            |    6 --
 drivers/firmware/google/gsmi.c                     |    3 -
 drivers/gpu/drm/i915/i915_dma.c                    |   19 ++----
 drivers/iommu/amd_iommu_init.c                     |    7 --
 drivers/md/bcache/bset.c                           |    3 -
 drivers/md/bcache/request.c                        |    3 -
 drivers/md/bcache/super.c                          |    9 +--
 drivers/md/dm-bufio.c                              |    3 -
 drivers/md/dm-cache-target.c                       |    3 -
 drivers/md/dm-crypt.c                              |    6 --
 drivers/md/dm-io.c                                 |    3 -
 drivers/md/dm-log-userspace-base.c                 |    3 -
 drivers/md/dm-region-hash.c                        |    4 -
 drivers/md/dm.c                                    |   13 +---
 drivers/md/multipath.c                             |    3 -
 drivers/md/raid1.c                                 |    6 --
 drivers/md/raid10.c                                |    9 +--
 drivers/md/raid5.c                                 |    3 -
 drivers/mtd/nand/nandsim.c                         |    3 -
 drivers/mtd/ubi/attach.c                           |    4 -
 drivers/net/ethernet/intel/ixgbe/ixgbe_fcoe.c      |    3 -
 drivers/staging/lustre/lustre/llite/super25.c      |   16 +----
 drivers/staging/lustre/lustre/obdclass/genops.c    |   24 ++------
 drivers/staging/lustre/lustre/obdclass/lu_object.c |    6 --
 drivers/staging/rdma/hfi1/user_sdma.c              |    3 -
 drivers/thunderbolt/ctl.c                          |    3 -
 drivers/usb/gadget/udc/bdc/bdc_core.c              |    3 -
 drivers/usb/gadget/udc/gr_udc.c                    |    3 -
 drivers/usb/gadget/udc/mv_u3d_core.c               |    3 -
 drivers/usb/gadget/udc/mv_udc_core.c               |    3 -
 drivers/usb/host/fotg210-hcd.c                     |   12 +---
 drivers/usb/host/fusbh200-hcd.c                    |   12 +---
 drivers/usb/host/whci/init.c                       |    3 -
 drivers/usb/host/xhci-mem.c                        |   12 +---
 fs/btrfs/backref.c                                 |    3 -
 fs/btrfs/delayed-inode.c                           |    3 -
 fs/btrfs/delayed-ref.c                             |   12 +---
 fs/btrfs/disk-io.c                                 |    3 -
 fs/btrfs/extent_io.c                               |    6 --
 fs/btrfs/extent_map.c                              |    3 -
 fs/btrfs/file.c                                    |    3 -
 fs/btrfs/inode.c                                   |   18 ++----
 fs/btrfs/ordered-data.c                            |    3 -
 fs/dlm/memory.c                                    |    6 --
 fs/ecryptfs/main.c                                 |    3 -
 fs/ext4/crypto.c                                   |    9 +--
 fs/ext4/extents_status.c                           |    3 -
 fs/ext4/mballoc.c                                  |    3 -
 fs/f2fs/crypto.c                                   |    9 +--
 fs/gfs2/main.c                                     |   29 ++--------
 fs/jbd2/journal.c                                  |   15 +----
 fs/jbd2/revoke.c                                   |   12 +---
 fs/jbd2/transaction.c                              |    6 --
 fs/jffs2/malloc.c                                  |   27 +++------
 fs/nfsd/nfscache.c                                 |    6 --
 fs/nilfs2/super.c                                  |   12 +---
 fs/ocfs2/dlm/dlmlock.c                             |    3 -
 fs/ocfs2/dlm/dlmmaster.c                           |   16 +----
 fs/ocfs2/super.c                                   |   18 ++----
 fs/ocfs2/uptodate.c                                |    3 -
 lib/debugobjects.c                                 |    3 -
 net/core/sock.c                                    |   12 +---
 net/dccp/ackvec.c                                  |   12 +---
 net/dccp/ccid.c                                    |    3 -
 net/sunrpc/sched.c                                 |   12 +---
 75 files changed, 180 insertions(+), 381 deletions(-)

[PATCH 10/39] atm: he: drop null test before destroy functions

[Julia Lawall]

Remove unneeded NULL test.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@ expression x; @@
-if (x != NULL)
  \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x);
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

---
 drivers/atm/he.c |    7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/atm/he.c b/drivers/atm/he.c
index a8da3a5..0f5cb37 100644
--- a/drivers/atm/he.c
+++ b/drivers/atm/he.c
@@ -1578,9 +1578,7 @@ he_stop(struct he_dev *he_dev)
 
 	kfree(he_dev->rbpl_virt);
 	kfree(he_dev->rbpl_table);
-
-	if (he_dev->rbpl_pool)
-		dma_pool_destroy(he_dev->rbpl_pool);
+	dma_pool_destroy(he_dev->rbpl_pool);
 
 	if (he_dev->rbrq_base)
 		dma_free_coherent(&he_dev->pci_dev->dev, CONFIG_RBRQ_SIZE * sizeof(struct he_rbrq),
@@ -1594,8 +1592,7 @@ he_stop(struct he_dev *he_dev)
 		dma_free_coherent(&he_dev->pci_dev->dev, CONFIG_TBRQ_SIZE * sizeof(struct he_tbrq),
 				  he_dev->tpdrq_base, he_dev->tpdrq_phys);
 
-	if (he_dev->tpd_pool)
-		dma_pool_destroy(he_dev->tpd_pool);
+	dma_pool_destroy(he_dev->tpd_pool);
 
 	if (he_dev->pci_dev) {
 		pci_read_config_word(he_dev->pci_dev, PCI_COMMAND, &command);

Re: [PATCH 10/39] atm: he: drop null test before destroy functions

[David Miller]

From: Julia Lawall <Julia.Lawall@lip6.fr>
Date: Sun, 13 Sep 2015 14:15:03 +0200

> Remove unneeded NULL test.
> 
> The semantic patch that makes this change is as follows:
> (http://coccinelle.lip6.fr/)
> 
> // <smpl>
> @@ expression x; @@
> -if (x != NULL)
>   \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x);
> // </smpl>
> 
> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

Applied.

[PATCH 14/39] SUNRPC: drop null test before destroy functions

[Julia Lawall]

Remove unneeded NULL test.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@ expression x; @@
-if (x != NULL)
  \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x);
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

---
 net/sunrpc/sched.c |   12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index b140c09..425ca2f 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -1092,14 +1092,10 @@ void
 rpc_destroy_mempool(void)
 {
 	rpciod_stop();
-	if (rpc_buffer_mempool)
-		mempool_destroy(rpc_buffer_mempool);
-	if (rpc_task_mempool)
-		mempool_destroy(rpc_task_mempool);
-	if (rpc_task_slabp)
-		kmem_cache_destroy(rpc_task_slabp);
-	if (rpc_buffer_slabp)
-		kmem_cache_destroy(rpc_buffer_slabp);
+	mempool_destroy(rpc_buffer_mempool);
+	mempool_destroy(rpc_task_mempool);
+	kmem_cache_destroy(rpc_task_slabp);
+	kmem_cache_destroy(rpc_buffer_slabp);
 	rpc_destroy_wait_queue(&delay_queue);
 }
 

Re: [PATCH 14/39] SUNRPC: drop null test before destroy functions

[J. Bruce Fields]

ACK, but assuming Trond takes this one.--b.

On Sun, Sep 13, 2015 at 02:15:07PM +0200, Julia Lawall wrote:
> Remove unneeded NULL test.
> 
> The semantic patch that makes this change is as follows:
> (http://coccinelle.lip6.fr/)
> 
> // <smpl>
> @@ expression x; @@
> -if (x != NULL)
>   \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x);
> // </smpl>
> 
> Signed-off-by: Julia Lawall <Julia.Lawall-L2FTfq7BK8M@public.gmane.org>
> 
> ---
>  net/sunrpc/sched.c |   12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
> index b140c09..425ca2f 100644
> --- a/net/sunrpc/sched.c
> +++ b/net/sunrpc/sched.c
> @@ -1092,14 +1092,10 @@ void
>  rpc_destroy_mempool(void)
>  {
>  	rpciod_stop();
> -	if (rpc_buffer_mempool)
> -		mempool_destroy(rpc_buffer_mempool);
> -	if (rpc_task_mempool)
> -		mempool_destroy(rpc_task_mempool);
> -	if (rpc_task_slabp)
> -		kmem_cache_destroy(rpc_task_slabp);
> -	if (rpc_buffer_slabp)
> -		kmem_cache_destroy(rpc_buffer_slabp);
> +	mempool_destroy(rpc_buffer_mempool);
> +	mempool_destroy(rpc_task_mempool);
> +	kmem_cache_destroy(rpc_task_slabp);
> +	kmem_cache_destroy(rpc_buffer_slabp);
>  	rpc_destroy_wait_queue(&delay_queue);
>  }
>  
--
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Re: [PATCH 14/39] SUNRPC: drop null test before destroy functions

[Trond Myklebust]

On Mon, Sep 14, 2015 at 12:07 PM, J. Bruce Fields <bfields@fieldses.org> wrote:
> ACK, but assuming Trond takes this one.--b.

No problem. I'll pick it up...

Cheers
  Trond

> On Sun, Sep 13, 2015 at 02:15:07PM +0200, Julia Lawall wrote:
>> Remove unneeded NULL test.
>>
>> The semantic patch that makes this change is as follows:
>> (http://coccinelle.lip6.fr/)
>>
>> // <smpl>
>> @@ expression x; @@
>> -if (x != NULL)
>>   \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x);
>> // </smpl>
>>
>> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
>>
>> ---
>>  net/sunrpc/sched.c |   12 ++++--------
>>  1 file changed, 4 insertions(+), 8 deletions(-)
>>
>> diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
>> index b140c09..425ca2f 100644
>> --- a/net/sunrpc/sched.c
>> +++ b/net/sunrpc/sched.c
>> @@ -1092,14 +1092,10 @@ void
>>  rpc_destroy_mempool(void)
>>  {
>>       rpciod_stop();
>> -     if (rpc_buffer_mempool)
>> -             mempool_destroy(rpc_buffer_mempool);
>> -     if (rpc_task_mempool)
>> -             mempool_destroy(rpc_task_mempool);
>> -     if (rpc_task_slabp)
>> -             kmem_cache_destroy(rpc_task_slabp);
>> -     if (rpc_buffer_slabp)
>> -             kmem_cache_destroy(rpc_buffer_slabp);
>> +     mempool_destroy(rpc_buffer_mempool);
>> +     mempool_destroy(rpc_task_mempool);
>> +     kmem_cache_destroy(rpc_task_slabp);
>> +     kmem_cache_destroy(rpc_buffer_slabp);
>>       rpc_destroy_wait_queue(&delay_queue);
>>  }
>>

[PATCH 20/39] ixgbe: drop null test before destroy functions

[Julia Lawall]

Remove unneeded NULL test.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@ expression x; @@
-if (x != NULL)
  \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x);
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

---
 drivers/net/ethernet/intel/ixgbe/ixgbe_fcoe.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_fcoe.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_fcoe.c
index 631c603..5f98870 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_fcoe.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_fcoe.c
@@ -620,8 +620,7 @@ static void ixgbe_fcoe_dma_pool_free(struct ixgbe_fcoe *fcoe, unsigned int cpu)
 	struct ixgbe_fcoe_ddp_pool *ddp_pool;
 
 	ddp_pool = per_cpu_ptr(fcoe->ddp_pool, cpu);
-	if (ddp_pool->pool)
-		dma_pool_destroy(ddp_pool->pool);
+	dma_pool_destroy(ddp_pool->pool);
 	ddp_pool->pool = NULL;
 }
 

[PATCH 25/39] net: core: drop null test before destroy functions

[Julia Lawall]

Remove unneeded NULL test.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@ expression x; @@
-if (x != NULL) {
  \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x);
  x = NULL;
-}
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

---
 net/core/sock.c |   12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/net/core/sock.c b/net/core/sock.c
index ca2984a..3307c02 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2740,10 +2740,8 @@ static void req_prot_cleanup(struct request_sock_ops *rsk_prot)
 		return;
 	kfree(rsk_prot->slab_name);
 	rsk_prot->slab_name = NULL;
-	if (rsk_prot->slab) {
-		kmem_cache_destroy(rsk_prot->slab);
-		rsk_prot->slab = NULL;
-	}
+	kmem_cache_destroy(rsk_prot->slab);
+	rsk_prot->slab = NULL;
 }
 
 static int req_prot_init(const struct proto *prot)
@@ -2828,10 +2826,8 @@ void proto_unregister(struct proto *prot)
 	list_del(&prot->node);
 	mutex_unlock(&proto_list_mutex);
 
-	if (prot->slab != NULL) {
-		kmem_cache_destroy(prot->slab);
-		prot->slab = NULL;
-	}
+	kmem_cache_destroy(prot->slab);
+	prot->slab = NULL;
 
 	req_prot_cleanup(prot->rsk_prot);
 

Re: [PATCH 25/39] net: core: drop null test before destroy functions

[David Miller]

From: Julia Lawall <Julia.Lawall@lip6.fr>
Date: Sun, 13 Sep 2015 14:15:18 +0200

> Remove unneeded NULL test.
> 
> The semantic patch that makes this change is as follows:
> (http://coccinelle.lip6.fr/)
> 
> // <smpl>
> @@ expression x; @@
> -if (x != NULL) {
>   \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x);
>   x = NULL;
> -}
> // </smpl>
> 
> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

Applied.

[PATCH 34/39] dccp: drop null test before destroy functions

[Julia Lawall]

Remove unneeded NULL test.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression x;
@@

-if (x != NULL)
  \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x);

@@
expression x;
@@

-if (x != NULL) {
  \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x);
  x = NULL;
-}
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

---
 net/dccp/ackvec.c |   12 ++++--------
 net/dccp/ccid.c   |    3 +--
 2 files changed, 5 insertions(+), 10 deletions(-)

diff --git a/net/dccp/ccid.c b/net/dccp/ccid.c
index 8349897..90f77d0 100644
--- a/net/dccp/ccid.c
+++ b/net/dccp/ccid.c
@@ -95,8 +95,7 @@ static struct kmem_cache *ccid_kmem_cache_create(int obj_size, char *slab_name_f
 
 static void ccid_kmem_cache_destroy(struct kmem_cache *slab)
 {
-	if (slab != NULL)
-		kmem_cache_destroy(slab);
+	kmem_cache_destroy(slab);
 }
 
 static int __init ccid_activate(struct ccid_operations *ccid_ops)
diff --git a/net/dccp/ackvec.c b/net/dccp/ackvec.c
index bd9e718..3de0d03 100644
--- a/net/dccp/ackvec.c
+++ b/net/dccp/ackvec.c
@@ -398,12 +398,8 @@ out_err:
 
 void dccp_ackvec_exit(void)
 {
-	if (dccp_ackvec_slab != NULL) {
-		kmem_cache_destroy(dccp_ackvec_slab);
-		dccp_ackvec_slab = NULL;
-	}
-	if (dccp_ackvec_record_slab != NULL) {
-		kmem_cache_destroy(dccp_ackvec_record_slab);
-		dccp_ackvec_record_slab = NULL;
-	}
+	kmem_cache_destroy(dccp_ackvec_slab);
+	dccp_ackvec_slab = NULL;
+	kmem_cache_destroy(dccp_ackvec_record_slab);
+	dccp_ackvec_record_slab = NULL;
 }

Re: [PATCH 34/39] dccp: drop null test before destroy functions

[David Miller]

From: Julia Lawall <Julia.Lawall@lip6.fr>
Date: Sun, 13 Sep 2015 14:15:27 +0200

> Remove unneeded NULL test.
> 
> The semantic patch that makes this change is as follows:
> (http://coccinelle.lip6.fr/)
> 
> // <smpl>
> @@
> expression x;
> @@
> 
> -if (x != NULL)
>   \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x);
> 
> @@
> expression x;
> @@
> 
> -if (x != NULL) {
>   \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x);
>   x = NULL;
> -}
> // </smpl>
> 
> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

Applied.

Re: [PATCH 00/39] drop null test before destroy functions

[SF Markus Elfring]

> Recent commits to kernel/git/torvalds/linux.git have made the following
> functions able to tolerate NULL arguments:
>
> kmem_cache_destroy (commit 3942d29918522)
> mempool_destroy (commit 4e3ca3e033d1)
> dma_pool_destroy (commit 44d7175da6ea)

How do you think about to extend an other SmPL script?

Related topic:
scripts/coccinelle/free: Delete NULL test before freeing functions
https://systeme.lip6.fr/pipermail/cocci/2015-May/001960.html
https://www.mail-archive.com/cocci@systeme.lip6.fr/msg01855.html


> If these changes are OK, I will address the remainder later.

Would anybody like to reuse my general SmPL approach for similar source
code clean-up?

Regards,
Markus