xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

lib/scatterlist: Provide a DMA page iterator

Browse Source 
Commit 2db76d7c3c ("lib/scatterlist: sg_page_iter: support sg lists w/o
backing pages") introduced the sg_page_iter_dma_address() function without
providing a way to use it in the general case. If the sg_dma_len() is not
equal to the sg length callers cannot safely use the
for_each_sg_page/sg_page_iter_dma_address combination.

Resolve this API mistake by providing a DMA specific iterator,
for_each_sg_dma_page(), that uses the right length so
sg_page_iter_dma_address() works as expected with all sglists.

A new iterator type is introduced to provide compile-time safety against
wrongly mixing accessors and iterators.

Acked-by: Christoph Hellwig <hch@lst.de> (for scatterlist)
Acked-by: Thomas Hellstrom <thellstrom@vmware.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> (ipu3-cio2)
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Jason Gunthorpe
2019-01-04 11:40:21 -07:00
parent f368ff188a
commit d901b2760d
5 changed files with 76 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/media/pci/intel/ipu3/ipu3-cio2.c
View File

@@ -846,7 +846,7 @@ static int cio2_vb2_buf_init(struct vb2_buffer *vb)
unsigned int pages = DIV_ROUND_UP(vb->planes[0].length, CIO2_PAGE_SIZE);
unsigned int lops = DIV_ROUND_UP(pages + 1, entries_per_page);
struct sg_table *sg;
struct sg_page_iter sg_iter;
struct sg_dma_page_iter sg_iter;
int i, j;
if (lops <= 0 || lops > CIO2_MAX_LOPS) {
@@ -873,7 +873,7 @@ static int cio2_vb2_buf_init(struct vb2_buffer *vb)
b->offset = sg->sgl->offset;
i = j = 0;
for_each_sg_page(sg->sgl, &sg_iter, sg->nents, 0) {
for_each_sg_dma_page (sg->sgl, &sg_iter, sg->nents, 0) {
if (!pages--)
break;
b->lop[i][j] = sg_page_iter_dma_address(&sg_iter) >> PAGE_SHIFT;