Thread (38 messages) flat view 38 messages, 4 authors, 2020-09-10

Re: [PATCH v10 30/30] videobuf2: use sgtable-based scatterlist wrappers

From: Tomasz Figa <tfiga@chromium.org>
Date: 2020-09-10 09:47:53
Also in: dri-devel, linux-iommu, linux-media, lkml

On Thu, Sep 10, 2020 at 11:17 AM Hans Verkuil [off-list ref] wrote:
On 04/09/2020 15:17, Marek Szyprowski wrote:
quoted
Use recently introduced common wrappers operating directly on the struct
sg_table objects and scatterlist page iterators to make the code a bit
more compact, robust, easier to follow and copy/paste safe.

No functional change, because the code already properly did all the
scatterlist related calls.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Hans Verkuil <redacted>

Note that I agree with Marek to keep returning -EIO. If we want to propagate
low-level errors, then that should be done in a separate patch. But I think EIO
is fine.
As I mentioned, there are 2 different cases here - UAPI and kAPI. I
agree that we should keep -EIO for UAPI, but kAPI is another story.
But if we're convinced that -EIO is also fine for the latter, I'm fine
with that.

Best regards,
Tomasz
Regards,

        Hans
quoted
---
 .../common/videobuf2/videobuf2-dma-contig.c   | 34 ++++++++-----------
 .../media/common/videobuf2/videobuf2-dma-sg.c | 32 +++++++----------
 .../common/videobuf2/videobuf2-vmalloc.c      | 12 +++----
 3 files changed, 31 insertions(+), 47 deletions(-)
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
index ec3446cc45b8..1b242d844dde 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
@@ -58,10 +58,10 @@ static unsigned long vb2_dc_get_contiguous_size(struct sg_table *sgt)
      unsigned int i;
      unsigned long size = 0;

-     for_each_sg(sgt->sgl, s, sgt->nents, i) {
+     for_each_sgtable_dma_sg(sgt, s, i) {
              if (sg_dma_address(s) != expected)
                      break;
-             expected = sg_dma_address(s) + sg_dma_len(s);
+             expected += sg_dma_len(s);
              size += sg_dma_len(s);
      }
      return size;
@@ -103,8 +103,7 @@ static void vb2_dc_prepare(void *buf_priv)
      if (!sgt)
              return;

-     dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->orig_nents,
-                            buf->dma_dir);
+     dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir);
 }

 static void vb2_dc_finish(void *buf_priv)
@@ -115,7 +114,7 @@ static void vb2_dc_finish(void *buf_priv)
      if (!sgt)
              return;

-     dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
+     dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);
 }

 /*********************************************/
@@ -275,8 +274,8 @@ static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf,
               * memory locations do not require any explicit cache
               * maintenance prior or after being used by the device.
               */
-             dma_unmap_sg_attrs(db_attach->dev, sgt->sgl, sgt->orig_nents,
-                                attach->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
+             dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir,
+                               DMA_ATTR_SKIP_CPU_SYNC);
      sg_free_table(sgt);
      kfree(attach);
      db_attach->priv = NULL;
@@ -301,8 +300,8 @@ static struct sg_table *vb2_dc_dmabuf_ops_map(

      /* release any previous cache */
      if (attach->dma_dir != DMA_NONE) {
-             dma_unmap_sg_attrs(db_attach->dev, sgt->sgl, sgt->orig_nents,
-                                attach->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
+             dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir,
+                               DMA_ATTR_SKIP_CPU_SYNC);
              attach->dma_dir = DMA_NONE;
      }
@@ -310,9 +309,8 @@ static struct sg_table *vb2_dc_dmabuf_ops_map(
       * mapping to the client with new direction, no cache sync
       * required see comment in vb2_dc_dmabuf_ops_detach()
       */
-     sgt->nents = dma_map_sg_attrs(db_attach->dev, sgt->sgl, sgt->orig_nents,
-                                   dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
-     if (!sgt->nents) {
+     if (dma_map_sgtable(db_attach->dev, sgt, dma_dir,
+                         DMA_ATTR_SKIP_CPU_SYNC)) {
              pr_err("failed to map scatterlist\n");
              mutex_unlock(lock);
              return ERR_PTR(-EIO);
@@ -455,8 +453,8 @@ static void vb2_dc_put_userptr(void *buf_priv)
               * No need to sync to CPU, it's already synced to the CPU
               * since the finish() memop will have been called before this.
               */
-             dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
-                                buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
+             dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir,
+                               DMA_ATTR_SKIP_CPU_SYNC);
              pages = frame_vector_pages(buf->vec);
              /* sgt should exist only if vector contains pages... */
              BUG_ON(IS_ERR(pages));
@@ -553,9 +551,8 @@ static void *vb2_dc_get_userptr(struct device *dev, unsigned long vaddr,
       * No need to sync to the device, this will happen later when the
       * prepare() memop is called.
       */
-     sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
-                                   buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
-     if (sgt->nents <= 0) {
+     if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir,
+                         DMA_ATTR_SKIP_CPU_SYNC)) {
              pr_err("failed to map scatterlist\n");
              ret = -EIO;
              goto fail_sgt_init;
@@ -577,8 +574,7 @@ static void *vb2_dc_get_userptr(struct device *dev, unsigned long vaddr,
      return buf;

 fail_map_sg:
-     dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
-                        buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
+     dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);

 fail_sgt_init:
      sg_free_table(sgt);
diff --git a/drivers/media/common/videobuf2/videobuf2-dma-sg.c b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
index 0a40e00f0d7e..0dd3b19025e0 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-sg.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-sg.c
@@ -148,9 +148,8 @@ static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs,
       * No need to sync to the device, this will happen later when the
       * prepare() memop is called.
       */
-     sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
-                                   buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
-     if (!sgt->nents)
+     if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir,
+                         DMA_ATTR_SKIP_CPU_SYNC))
              goto fail_map;

      buf->handler.refcount = &buf->refcount;
@@ -186,8 +185,8 @@ static void vb2_dma_sg_put(void *buf_priv)
      if (refcount_dec_and_test(&buf->refcount)) {
              dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,
                      buf->num_pages);
-             dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
-                                buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
+             dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir,
+                               DMA_ATTR_SKIP_CPU_SYNC);
              if (buf->vaddr)
                      vm_unmap_ram(buf->vaddr, buf->num_pages);
              sg_free_table(buf->dma_sgt);
@@ -204,8 +203,7 @@ static void vb2_dma_sg_prepare(void *buf_priv)
      struct vb2_dma_sg_buf *buf = buf_priv;
      struct sg_table *sgt = buf->dma_sgt;

-     dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->orig_nents,
-                            buf->dma_dir);
+     dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir);
 }

 static void vb2_dma_sg_finish(void *buf_priv)
@@ -213,7 +211,7 @@ static void vb2_dma_sg_finish(void *buf_priv)
      struct vb2_dma_sg_buf *buf = buf_priv;
      struct sg_table *sgt = buf->dma_sgt;

-     dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
+     dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);
 }

 static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr,
@@ -256,9 +254,8 @@ static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr,
       * No need to sync to the device, this will happen later when the
       * prepare() memop is called.
       */
-     sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
-                                   buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
-     if (!sgt->nents)
+     if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir,
+                         DMA_ATTR_SKIP_CPU_SYNC))
              goto userptr_fail_map;

      return buf;
@@ -284,8 +281,7 @@ static void vb2_dma_sg_put_userptr(void *buf_priv)

      dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
             __func__, buf->num_pages);
-     dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir,
-                        DMA_ATTR_SKIP_CPU_SYNC);
+     dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
      if (buf->vaddr)
              vm_unmap_ram(buf->vaddr, buf->num_pages);
      sg_free_table(buf->dma_sgt);
@@ -408,8 +404,7 @@ static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf,

      /* release the scatterlist cache */
      if (attach->dma_dir != DMA_NONE)
-             dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
-                     attach->dma_dir);
+             dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0);
      sg_free_table(sgt);
      kfree(attach);
      db_attach->priv = NULL;
@@ -434,15 +429,12 @@ static struct sg_table *vb2_dma_sg_dmabuf_ops_map(

      /* release any previous cache */
      if (attach->dma_dir != DMA_NONE) {
-             dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
-                     attach->dma_dir);
+             dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0);
              attach->dma_dir = DMA_NONE;
      }

      /* mapping to the client with new direction */
-     sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
-                             dma_dir);
-     if (!sgt->nents) {
+     if (dma_map_sgtable(db_attach->dev, sgt, dma_dir, 0)) {
              pr_err("failed to map scatterlist\n");
              mutex_unlock(lock);
              return ERR_PTR(-EIO);
diff --git a/drivers/media/common/videobuf2/videobuf2-vmalloc.c b/drivers/media/common/videobuf2/videobuf2-vmalloc.c
index c66fda4a65e4..bf5ac63a5742 100644
--- a/drivers/media/common/videobuf2/videobuf2-vmalloc.c
+++ b/drivers/media/common/videobuf2/videobuf2-vmalloc.c
@@ -229,7 +229,7 @@ static int vb2_vmalloc_dmabuf_ops_attach(struct dma_buf *dbuf,
              kfree(attach);
              return ret;
      }
-     for_each_sg(sgt->sgl, sg, sgt->nents, i) {
+     for_each_sgtable_sg(sgt, sg, i) {
              struct page *page = vmalloc_to_page(vaddr);

              if (!page) {
@@ -259,8 +259,7 @@ static void vb2_vmalloc_dmabuf_ops_detach(struct dma_buf *dbuf,

      /* release the scatterlist cache */
      if (attach->dma_dir != DMA_NONE)
-             dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
-                     attach->dma_dir);
+             dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0);
      sg_free_table(sgt);
      kfree(attach);
      db_attach->priv = NULL;
@@ -285,15 +284,12 @@ static struct sg_table *vb2_vmalloc_dmabuf_ops_map(

      /* release any previous cache */
      if (attach->dma_dir != DMA_NONE) {
-             dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
-                     attach->dma_dir);
+             dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, 0);
              attach->dma_dir = DMA_NONE;
      }

      /* mapping to the client with new direction */
-     sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
-                             dma_dir);
-     if (!sgt->nents) {
+     if (dma_map_sgtable(db_attach->dev, sgt, dma_dir, 0)) {
              pr_err("failed to map scatterlist\n");
              mutex_unlock(lock);
              return ERR_PTR(-EIO);
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