Commit 8dc39cfc authored by Thomas Hellstrom's avatar Thomas Hellstrom
Browse files

drm/vmwgfx: Use the dma scatter-gather iterator to get dma addresses 



Use struct sg_dma_page_iter in favour struct of sg_page_iter, which fairly
recently was declared useless for obtaining dma addresses.

With a struct sg_dma_page_iter we can't call sg_page_iter_page() so
when the page is needed, use the same page lookup mechanism as for the
non-sg dma modes instead of calling sg_dma_page_iter.

Note, the fixes tag doesn't really point to a commit introducing a
failure / regression, but rather to a commit that implemented a simple
workaround for this problem.

Cc: Jason Gunthorpe <jgg@mellanox.com>
Fixes: d901b276 ("lib/scatterlist: Provide a DMA page iterator")
Signed-off-by: default avatarThomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@mellanox.com>
parent e41c20cf

drivers/gpu/drm/vmwgfx/vmwgfx_drv.h

+1 −1
Original line number Original line Diff line number Diff line
@@ -296,7 +296,7 @@ struct vmw_sg_table { 
struct vmw_piter {

struct vmw_piter {

	struct page **pages;

	struct page **pages;

	const dma_addr_t *addrs;

	const dma_addr_t *addrs;

	struct sg_page_iter iter;

	struct sg_dma_page_iter iter;

	unsigned long i;

	unsigned long i;

	unsigned long num_pages;

	unsigned long num_pages;

	bool (*next)(struct vmw_piter *);

	bool (*next)(struct vmw_piter *);

drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c

+7 −20
Original line number Original line Diff line number Diff line
@@ -266,7 +266,9 @@ static bool __vmw_piter_non_sg_next(struct vmw_piter *viter) 




static bool __vmw_piter_sg_next(struct vmw_piter *viter)

static bool __vmw_piter_sg_next(struct vmw_piter *viter)

{

{

	return __sg_page_iter_next(&viter->iter);

	bool ret = __vmw_piter_non_sg_next(viter);



	return __sg_page_iter_dma_next(&viter->iter) && ret;

}

}
@@ -284,12 +286,6 @@ static struct page *__vmw_piter_non_sg_page(struct vmw_piter *viter) 
	return viter->pages[viter->i];

	return viter->pages[viter->i];

}

}





static struct page *__vmw_piter_sg_page(struct vmw_piter *viter)

{

	return sg_page_iter_page(&viter->iter);

}





/**

/**

 * Helper functions to return the DMA address of the current page.

 * Helper functions to return the DMA address of the current page.

 *

 *
@@ -311,13 +307,7 @@ static dma_addr_t __vmw_piter_dma_addr(struct vmw_piter *viter) 




static dma_addr_t __vmw_piter_sg_addr(struct vmw_piter *viter)

static dma_addr_t __vmw_piter_sg_addr(struct vmw_piter *viter)

{

{

	/*

	return sg_page_iter_dma_address(&viter->iter);

	 * FIXME: This driver wrongly mixes DMA and CPU SG list iteration and

	 * needs revision. See

	 * https://lore.kernel.org/lkml/20190104223531.GA1705@ziepe.ca/

	 */

	return sg_page_iter_dma_address(

		container_of(&viter->iter, struct sg_dma_page_iter, base));

}

}
@@ -336,26 +326,23 @@ void vmw_piter_start(struct vmw_piter *viter, const struct vmw_sg_table *vsgt, 
{

{

	viter->i = p_offset - 1;

	viter->i = p_offset - 1;

	viter->num_pages = vsgt->num_pages;

	viter->num_pages = vsgt->num_pages;

	viter->page = &__vmw_piter_non_sg_page;

	viter->pages = vsgt->pages;

	switch (vsgt->mode) {

	switch (vsgt->mode) {

	case vmw_dma_phys:

	case vmw_dma_phys:

		viter->next = &__vmw_piter_non_sg_next;

		viter->next = &__vmw_piter_non_sg_next;

		viter->dma_address = &__vmw_piter_phys_addr;

		viter->dma_address = &__vmw_piter_phys_addr;

		viter->page = &__vmw_piter_non_sg_page;

		viter->pages = vsgt->pages;

		break;

		break;

	case vmw_dma_alloc_coherent:

	case vmw_dma_alloc_coherent:

		viter->next = &__vmw_piter_non_sg_next;

		viter->next = &__vmw_piter_non_sg_next;

		viter->dma_address = &__vmw_piter_dma_addr;

		viter->dma_address = &__vmw_piter_dma_addr;

		viter->page = &__vmw_piter_non_sg_page;

		viter->addrs = vsgt->addrs;

		viter->addrs = vsgt->addrs;

		viter->pages = vsgt->pages;

		break;

		break;

	case vmw_dma_map_populate:

	case vmw_dma_map_populate:

	case vmw_dma_map_bind:

	case vmw_dma_map_bind:

		viter->next = &__vmw_piter_sg_next;

		viter->next = &__vmw_piter_sg_next;

		viter->dma_address = &__vmw_piter_sg_addr;

		viter->dma_address = &__vmw_piter_sg_addr;

		viter->page = &__vmw_piter_sg_page;

		__sg_page_iter_start(&viter->iter.base, vsgt->sgt->sgl,

		__sg_page_iter_start(&viter->iter, vsgt->sgt->sgl,

				     vsgt->sgt->orig_nents, p_offset);

				     vsgt->sgt->orig_nents, p_offset);

		break;

		break;

	default:

	default:

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