[PATCH V3 09/15] s390: zfcp_fc: use sg helper to operate scatterlist

[PATCH V3 09/15] s390: zfcp_fc: use sg helper to operate scatterlist

[Ming Lei]

Use the scatterlist iterators and remove direct indexing of the
scatterlist array.

This way allows us to pre-allocate one small scatterlist, which can be
chained with one runtime allocated scatterlist if the pre-allocated one
isn't enough for the whole request.

Cc: Steffen Maier <maier@linux.ibm.com>
Cc: Benjamin Block <bblock@linux.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux-s390@vger.kernel.org
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 drivers/s390/scsi/zfcp_fc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/s390/scsi/zfcp_fc.c b/drivers/s390/scsi/zfcp_fc.c
index 33eddb02ee30..b018b61bd168 100644
--- a/drivers/s390/scsi/zfcp_fc.c
+++ b/drivers/s390/scsi/zfcp_fc.c
@@ -620,7 +620,7 @@ static void zfcp_fc_sg_free_table(struct scatterlist *sg, int count)
 {
 	int i;
 
-	for (i = 0; i < count; i++, sg++)
+	for (i = 0; i < count; i++, sg = sg_next(sg))
 		if (sg)
 			free_page((unsigned long) sg_virt(sg));
 		else
@@ -641,7 +641,7 @@ static int zfcp_fc_sg_setup_table(struct scatterlist *sg, int count)
 	int i;
 
 	sg_init_table(sg, count);
-	for (i = 0; i < count; i++, sg++) {
+	for (i = 0; i < count; i++, sg = sg_next(sg)) {
 		addr = (void *) get_zeroed_page(GFP_KERNEL);
 		if (!addr) {
 			zfcp_fc_sg_free_table(sg, i);
-- 
2.20.1

Re: [PATCH V3 09/15] s390: zfcp_fc: use sg helper to operate scatterlist

[Benjamin Block]

On Fri, Jun 14, 2019 at 10:53:10AM +0800, Ming Lei wrote:
> Use the scatterlist iterators and remove direct indexing of the
> scatterlist array.
> 
> This way allows us to pre-allocate one small scatterlist, which can be
> chained with one runtime allocated scatterlist if the pre-allocated one
> isn't enough for the whole request.
> 
> Cc: Steffen Maier <maier@linux.ibm.com>
> Cc: Benjamin Block <bblock@linux.ibm.com>
> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
> Cc: linux-s390@vger.kernel.org
> Signed-off-by: Ming Lei <ming.lei@redhat.com>
> ---
>  drivers/s390/scsi/zfcp_fc.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/s390/scsi/zfcp_fc.c b/drivers/s390/scsi/zfcp_fc.c
> index 33eddb02ee30..b018b61bd168 100644
> --- a/drivers/s390/scsi/zfcp_fc.c
> +++ b/drivers/s390/scsi/zfcp_fc.c
> @@ -620,7 +620,7 @@ static void zfcp_fc_sg_free_table(struct scatterlist *sg, int count)
>  {
>  	int i;
>  
> -	for (i = 0; i < count; i++, sg++)
> +	for (i = 0; i < count; i++, sg = sg_next(sg))
>  		if (sg)
>  			free_page((unsigned long) sg_virt(sg));
>  		else
> @@ -641,7 +641,7 @@ static int zfcp_fc_sg_setup_table(struct scatterlist *sg, int count)
>  	int i;
>  
>  	sg_init_table(sg, count);
> -	for (i = 0; i < count; i++, sg++) {
> +	for (i = 0; i < count; i++, sg = sg_next(sg)) {
>  		addr = (void *) get_zeroed_page(GFP_KERNEL);
>  		if (!addr) {
>  			zfcp_fc_sg_free_table(sg, i);

Acked-by: Benjamin Block <bblock@linux.ibm.com>

-- 
With Best Regards, Benjamin Block      /      Linux on IBM Z Kernel Development
IBM Systems & Technology Group   /  IBM Deutschland Research & Development GmbH
Vorsitz. AufsR.: Matthias Hartmann       /      Gesch�ftsf�hrung: Dirk Wittkopp
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