diff options
| author | Mitchell Horne <mhorne@FreeBSD.org> | 2023-12-06 23:08:51 +0000 |
|---|---|---|
| committer | Mitchell Horne <mhorne@FreeBSD.org> | 2023-12-06 23:11:39 +0000 |
| commit | 1228b93b410a299cc2a730fe4b065bcffeb162c2 (patch) | |
| tree | 3d137bc2d3f089473e78b87c4dfd91da5ba49e3f /sys/arm | |
| parent | 900907f4399f40f1088ea5f353b54c868daf630e (diff) | |
busdma: remove parent tag tracking
Without filter functions, we do not need to keep track of tag ancestry.
All inheritance of the parent tag's parameters occurs when creating the
new child tag.
Reviewed by: jhb
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D42895
Diffstat (limited to 'sys/arm')
| -rw-r--r-- | sys/arm/arm/busdma_machdep.c | 60 |
1 files changed, 8 insertions, 52 deletions
diff --git a/sys/arm/arm/busdma_machdep.c b/sys/arm/arm/busdma_machdep.c index cf1fd0209734..dd31f7779b21 100644 --- a/sys/arm/arm/busdma_machdep.c +++ b/sys/arm/arm/busdma_machdep.c @@ -77,7 +77,6 @@ struct bounce_page; struct bounce_zone; struct bus_dma_tag { - bus_dma_tag_t parent; bus_size_t alignment; bus_addr_t boundary; bus_addr_t lowaddr; @@ -86,7 +85,6 @@ struct bus_dma_tag { u_int nsegments; bus_size_t maxsegsz; int flags; - int ref_count; int map_count; bus_dma_lock_t *lockfunc; void *lockfuncarg; @@ -332,10 +330,7 @@ might_bounce(bus_dma_tag_t dmat, bus_dmamap_t map, bus_addr_t addr, * * Bouncing can be triggered by DMA that doesn't begin and end on cacheline * boundaries, or doesn't begin on an alignment boundary, or falls within the - * exclusion zone of any tag in the ancestry chain. - * - * For exclusions, walk the chain of tags comparing paddr to the exclusion zone - * within each tag. + * exclusion zone of the tag. */ static int must_bounce(bus_dma_tag_t dmat, bus_dmamap_t map, bus_addr_t paddr, @@ -353,17 +348,11 @@ must_bounce(bus_dma_tag_t dmat, bus_dmamap_t map, bus_addr_t paddr, return (1); /* - * Even though each tag has an exclusion zone that is a superset of its - * own and all its ancestors' exclusions, the exclusion zone of each tag - * up the chain must be checked within the loop, because the busdma - * rules say the filter function is called only when the address lies - * within the low-highaddr range of the tag that filterfunc belongs to. + * Check the tag's exclusion zone. */ - while (dmat != NULL && exclusion_bounce(dmat)) { - if (paddr >= dmat->lowaddr && paddr <= dmat->highaddr) - return (1); - dmat = dmat->parent; - } + if (exclusion_bounce(dmat) && + paddr >= dmat->lowaddr && paddr <= dmat->highaddr) + return (1); return (0); } @@ -405,7 +394,6 @@ bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment, return (ENOMEM); } - newtag->parent = parent; newtag->alignment = alignment; newtag->boundary = boundary; newtag->lowaddr = trunc_page((vm_paddr_t)lowaddr) + (PAGE_SIZE - 1); @@ -415,7 +403,6 @@ bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment, newtag->nsegments = nsegments; newtag->maxsegsz = maxsegsz; newtag->flags = flags; - newtag->ref_count = 1; /* Count ourself */ newtag->map_count = 0; if (lockfunc != NULL) { newtag->lockfunc = lockfunc; @@ -437,14 +424,6 @@ bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment, else if (parent->boundary != 0) newtag->boundary = MIN(parent->boundary, newtag->boundary); - - /* - * Short circuit to looking at our parent directly since we - * have encapsulated all of its information. - */ - newtag->parent = parent->parent; - if (newtag->parent != NULL) - atomic_add_int(&parent->ref_count, 1); } if (exclusion_bounce_check(newtag->lowaddr, newtag->highaddr)) @@ -504,7 +483,6 @@ bus_dma_template_clone(bus_dma_template_t *t, bus_dma_tag_t dmat) if (t == NULL || dmat == NULL) return; - t->parent = dmat->parent; t->alignment = dmat->alignment; t->boundary = dmat->boundary; t->lowaddr = dmat->lowaddr; @@ -527,39 +505,17 @@ bus_dma_tag_set_domain(bus_dma_tag_t dmat, int domain) int bus_dma_tag_destroy(bus_dma_tag_t dmat) { -#ifdef KTR - bus_dma_tag_t dmat_copy = dmat; -#endif - int error; - - error = 0; + int error = 0; if (dmat != NULL) { if (dmat->map_count != 0) { error = EBUSY; goto out; } - - while (dmat != NULL) { - bus_dma_tag_t parent; - - parent = dmat->parent; - atomic_subtract_int(&dmat->ref_count, 1); - if (dmat->ref_count == 0) { - atomic_subtract_32(&tags_total, 1); - free(dmat, M_BUSDMA); - /* - * Last reference count, so - * release our reference - * count on our parent. - */ - dmat = parent; - } else - dmat = NULL; - } + free(dmat, M_BUSDMA); } out: - CTR3(KTR_BUSDMA, "%s tag %p error %d", __func__, dmat_copy, error); + CTR3(KTR_BUSDMA, "%s tag %p error %d", __func__, dmat, error); return (error); } |