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Groups > linux.kernel > #1623391

[PATCH 16/22] xen-blkfront: Make use of the new sg_map helper function

From Logan Gunthorpe <logang@deltatee.com>
Newsgroups linux.kernel
Subject [PATCH 16/22] xen-blkfront: Make use of the new sg_map helper function
Date 2017-04-14 00:20 +0200
Message-ID <tvVfQ-Tr-17@gated-at.bofh.it> (permalink)
References <tvV69-P8-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Straightforward conversion to the new helper, except due to
the lack of error path, we have to warn if unmapable memory
is ever present in the sgl.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
---
 drivers/block/xen-blkfront.c | 33 +++++++++++++++++++++++++++------
 1 file changed, 27 insertions(+), 6 deletions(-)

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 5067a0a..7dcf41d 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -807,8 +807,19 @@ static int blkif_queue_rw_req(struct request *req, struct blkfront_ring_info *ri
 		BUG_ON(sg->offset + sg->length > PAGE_SIZE);
 
 		if (setup.need_copy) {
-			setup.bvec_off = sg->offset;
-			setup.bvec_data = kmap_atomic(sg_page(sg));
+			setup.bvec_off = 0;
+			setup.bvec_data = sg_map(sg, SG_KMAP_ATOMIC);
+			if (IS_ERR(setup.bvec_data)) {
+				/*
+				 * This should really never happen unless
+				 * the code is changed to use memory that is
+				 * not mappable in the sg. Seeing there is a
+				 * questionable error path out of here,
+				 * we WARN.
+				 */
+				WARN(1, "Non-mappable memory used in sg!");
+				return 1;
+			}
 		}
 
 		gnttab_foreach_grant_in_range(sg_page(sg),
@@ -818,7 +829,7 @@ static int blkif_queue_rw_req(struct request *req, struct blkfront_ring_info *ri
 					      &setup);
 
 		if (setup.need_copy)
-			kunmap_atomic(setup.bvec_data);
+			sg_unmap(sg, setup.bvec_data, SG_KMAP_ATOMIC);
 	}
 	if (setup.segments)
 		kunmap_atomic(setup.segments);
@@ -1468,8 +1479,18 @@ static bool blkif_completion(unsigned long *id,
 		for_each_sg(s->sg, sg, num_sg, i) {
 			BUG_ON(sg->offset + sg->length > PAGE_SIZE);
 
-			data.bvec_offset = sg->offset;
-			data.bvec_data = kmap_atomic(sg_page(sg));
+			data.bvec_offset = 0;
+			data.bvec_data = sg_map(sg, SG_KMAP_ATOMIC);
+			if (IS_ERR(data.bvec_data)) {
+				/*
+				 * This should really never happen unless
+				 * the code is changed to use memory that is
+				 * not mappable in the sg. Seeing there is no
+				 * clear error path, we WARN.
+				 */
+				WARN(1, "Non-mappable memory used in sg!");
+				return 1;
+			}
 
 			gnttab_foreach_grant_in_range(sg_page(sg),
 						      sg->offset,
@@ -1477,7 +1498,7 @@ static bool blkif_completion(unsigned long *id,
 						      blkif_copy_from_grant,
 						      &data);
 
-			kunmap_atomic(data.bvec_data);
+			sg_unmap(sg, data.bvec_data, SG_KMAP_ATOMIC);
 		}
 	}
 	/* Add the persistent grant into the list of free grants */
-- 
2.1.4

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Thread

[PATCH 00/22] Introduce common scatterlist map function Logan Gunthorpe <logang@deltatee.com> - 2017-04-14 00:20 +0200
  [PATCH 18/22] mmc: spi: Make use of the new sg_map helper function Logan Gunthorpe <logang@deltatee.com> - 2017-04-14 00:20 +0200
  [PATCH 06/22] crypto: hifn_795x: Make use of the new sg_map helper function Logan Gunthorpe <logang@deltatee.com> - 2017-04-14 00:20 +0200
  [PATCH 04/22] target: Make use of the new sg_map function at 16 call sites Logan Gunthorpe <logang@deltatee.com> - 2017-04-14 00:20 +0200
  [PATCH 16/22] xen-blkfront: Make use of the new sg_map helper function Logan Gunthorpe <logang@deltatee.com> - 2017-04-14 00:20 +0200
    RE: [PATCH 16/22] xen-blkfront: Make use of the new sg_map helper  function David Laight <David.Laight@ACULAB.COM> - 2017-04-18 16:20 +0200
      Re: [PATCH 16/22] xen-blkfront: Make use of the new sg_map helper  function Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> - 2017-04-18 16:40 +0200
        Re: [PATCH 16/22] xen-blkfront: Make use of the new sg_map helper  function Logan Gunthorpe <logang@deltatee.com> - 2017-04-18 17:50 +0200
          Re: [PATCH 16/22] xen-blkfront: Make use of the new sg_map helper  function Logan Gunthorpe <logang@deltatee.com> - 2017-04-18 18:00 +0200
          Re: [PATCH 16/22] xen-blkfront: Make use of the new sg_map helper  function Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> - 2017-04-18 18:00 +0200
  [PATCH 10/22] staging: unisys: visorbus: Make use of the new sg_map helper function Logan Gunthorpe <logang@deltatee.com> - 2017-04-14 00:20 +0200
    RE: [PATCH 10/22] staging: unisys: visorbus: Make use of the new  sg_map helper function "Kershner, David A" <David.Kershner@unisys.com> - 2017-04-14 18:10 +0200
      Re: [PATCH 10/22] staging: unisys: visorbus: Make use of the new  sg_map helper function Logan Gunthorpe <logang@deltatee.com> - 2017-04-14 18:20 +0200
  [PATCH 07/22] crypto: shash, caam: Make use of the new sg_map helper function Logan Gunthorpe <logang@deltatee.com> - 2017-04-14 00:20 +0200
  [PATCH 12/22] scsi: ipr, pmcraid, isci: Make use of the new sg_map helper in 4 call sites Logan Gunthorpe <logang@deltatee.com> - 2017-04-14 00:20 +0200
  [PATCH 15/22] scsi: libfc, csiostor: Change to sg_copy_buffer in two drivers Logan Gunthorpe <logang@deltatee.com> - 2017-04-14 00:20 +0200
  [PATCH 17/22] mmc: sdhci: Make use of the new sg_map helper function Logan Gunthorpe <logang@deltatee.com> - 2017-04-14 00:20 +0200
  [PATCH 22/22] memstick: Make use of the new sg_map helper function Logan Gunthorpe <logang@deltatee.com> - 2017-04-14 00:20 +0200
  [PATCH 19/22] mmc: tmio: Make use of the new sg_map helper function Logan Gunthorpe <logang@deltatee.com> - 2017-04-14 00:20 +0200
  [PATCH 02/22] nvmet: Make use of the new sg_map helper function Logan Gunthorpe <logang@deltatee.com> - 2017-04-14 00:20 +0200
    Re: [PATCH 02/22] nvmet: Make use of the new sg_map helper function Christoph Hellwig <hch@lst.de> - 2017-04-14 07:10 +0200
      Re: [PATCH 02/22] nvmet: Make use of the new sg_map helper function Logan Gunthorpe <logang@deltatee.com> - 2017-04-14 07:10 +0200
        Re: [PATCH 02/22] nvmet: Make use of the new sg_map helper function Christoph Hellwig <hch@lst.de> - 2017-04-14 07:20 +0200
  [PATCH 05/22] drm/i915: Make use of the new sg_map helper function Logan Gunthorpe <logang@deltatee.com> - 2017-04-14 00:20 +0200
    Re: [PATCH 05/22] drm/i915: Make use of the new sg_map helper  function Daniel Vetter <daniel@ffwll.ch> - 2017-04-18 08:50 +0200
      Re: [PATCH 05/22] drm/i915: Make use of the new sg_map helper  function Logan Gunthorpe <logang@deltatee.com> - 2017-04-18 17:50 +0200

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