Re: [PATCH net-next 01/14] net/smc: Remove error handling of unregister_dmb()

[Dust Li <dust.li@linux.alibaba.com>]

On 2025-09-05 16:54:14, Alexandra Winter wrote:
>smcd_buf_free() calls smc_ism_unregister_dmb(lgr->smcd, buf_desc) and
>then unconditionally frees buf_desc.
>
>Remove the cleaning up of fields of buf_desc in
>smc_ism_unregister_dmb(), because it is not helpful.
>
>This removes the only usage of ISM_ERROR from the smc module. So move it
>to drivers/s390/net/ism.h.
>
>Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
>Reviewed-by: Mahanta Jambigi <mjambigi@linux.ibm.com>

Reviewed-by: Dust Li <dust.li@linux.alibaba.com>

Best regards,
Dust

>---
> drivers/s390/net/ism.h |  1 +
> include/net/smc.h      |  2 --
> net/smc/smc_ism.c      | 14 +++++---------
> net/smc/smc_ism.h      |  3 ++-
> 4 files changed, 8 insertions(+), 12 deletions(-)
>
>diff --git a/drivers/s390/net/ism.h b/drivers/s390/net/ism.h
>index 047fa6101555..b5b03db52fce 100644
>--- a/drivers/s390/net/ism.h
>+++ b/drivers/s390/net/ism.h
>@@ -10,6 +10,7 @@
> #include <asm/pci_insn.h>
> 
> #define UTIL_STR_LEN	16
>+#define ISM_ERROR	0xFFFF
> 
> /*
>  * Do not use the first word of the DMB bits to ensure 8 byte aligned access.
>diff --git a/include/net/smc.h b/include/net/smc.h
>index db84e4e35080..a9c023dd1380 100644
>--- a/include/net/smc.h
>+++ b/include/net/smc.h
>@@ -44,8 +44,6 @@ struct smcd_dmb {
> 
> #define ISM_RESERVED_VLANID	0x1FFF
> 
>-#define ISM_ERROR	0xFFFF
>-
> struct smcd_dev;
> 
> struct smcd_gid {
>diff --git a/net/smc/smc_ism.c b/net/smc/smc_ism.c
>index a58ffb7a0610..fca01b95b65a 100644
>--- a/net/smc/smc_ism.c
>+++ b/net/smc/smc_ism.c
>@@ -205,13 +205,13 @@ int smc_ism_put_vlan(struct smcd_dev *smcd, unsigned short vlanid)
> 	return rc;
> }
> 
>-int smc_ism_unregister_dmb(struct smcd_dev *smcd, struct smc_buf_desc *dmb_desc)
>+void smc_ism_unregister_dmb(struct smcd_dev *smcd,
>+			    struct smc_buf_desc *dmb_desc)
> {
> 	struct smcd_dmb dmb;
>-	int rc = 0;
> 
> 	if (!dmb_desc->dma_addr)
>-		return rc;
>+		return;
> 
> 	memset(&dmb, 0, sizeof(dmb));
> 	dmb.dmb_tok = dmb_desc->token;
>@@ -219,13 +219,9 @@ int smc_ism_unregister_dmb(struct smcd_dev *smcd, struct smc_buf_desc *dmb_desc)
> 	dmb.cpu_addr = dmb_desc->cpu_addr;
> 	dmb.dma_addr = dmb_desc->dma_addr;
> 	dmb.dmb_len = dmb_desc->len;
>-	rc = smcd->ops->unregister_dmb(smcd, &dmb);
>-	if (!rc || rc == ISM_ERROR) {
>-		dmb_desc->cpu_addr = NULL;
>-		dmb_desc->dma_addr = 0;
>-	}
>+	smcd->ops->unregister_dmb(smcd, &dmb);
> 
>-	return rc;
>+	return;
> }
> 
> int smc_ism_register_dmb(struct smc_link_group *lgr, int dmb_len,
>diff --git a/net/smc/smc_ism.h b/net/smc/smc_ism.h
>index 6763133dd8d0..765aa8fae6fa 100644
>--- a/net/smc/smc_ism.h
>+++ b/net/smc/smc_ism.h
>@@ -47,7 +47,8 @@ int smc_ism_get_vlan(struct smcd_dev *dev, unsigned short vlan_id);
> int smc_ism_put_vlan(struct smcd_dev *dev, unsigned short vlan_id);
> int smc_ism_register_dmb(struct smc_link_group *lgr, int buf_size,
> 			 struct smc_buf_desc *dmb_desc);
>-int smc_ism_unregister_dmb(struct smcd_dev *dev, struct smc_buf_desc *dmb_desc);
>+void smc_ism_unregister_dmb(struct smcd_dev *dev,
>+			    struct smc_buf_desc *dmb_desc);
> bool smc_ism_support_dmb_nocopy(struct smcd_dev *smcd);
> int smc_ism_attach_dmb(struct smcd_dev *dev, u64 token,
> 		       struct smc_buf_desc *dmb_desc);
>-- 
>2.48.1