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authorMing Lei <ming.lei@redhat.com>2019-06-18 04:37:51 +0300
committerMartin K. Petersen <martin.petersen@oracle.com>2019-06-20 22:21:33 +0300
commit013be03840c2ba3a2717f9cee457f01fdc4d8436 (patch)
tree304851d932a594759898f98b01757ca96c78b1ef /drivers/s390/scsi
parentda5567369fb686eb050da15364f11ef561f9a03e (diff)
downloadlinux-013be03840c2ba3a2717f9cee457f01fdc4d8436.tar.xz
scsi: s390: zfcp_fc: use sg helper to iterate over scatterlist
Unlike the legacy I/O path, scsi-mq preallocates a large array to hold the scatterlist for each request. This static allocation can consume substantial amounts of memory on modern controllers which support a large number of concurrently outstanding requests. To facilitate a switch to a smaller static allocation combined with a dynamic allocation for requests that need it, we need to make sure all SCSI drivers handle chained scatterlists correctly. Convert remaining drivers that directly dereference the scatterlist array to using the iterator functions. [mkp: clarified commit message] 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 Acked-by: Benjamin Block <bblock@linux.ibm.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/s390/scsi')
-rw-r--r--drivers/s390/scsi/zfcp_fc.c4
1 files 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);