The branch stable/13 has been updated by dougm:
URL:
https://cgit.FreeBSD.org/src/commit/?id=4d517feaea0352aea8828a4a07c40ff85036010d
commit 4d517feaea0352aea8828a4a07c40ff85036010d
Author: Doug Moore <do...@freebsd.org>
AuthorDate: 2022-06-02 20:59:57 +0000
Commit: Doug Moore <do...@freebsd.org>
CommitDate: 2022-06-27 05:34:59 +0000
busdma_iommu: simplify split logic
iommu_bus_dmamap_load_something1 includes code for handling the
possibility of splitting a buffer that is needlessly complex.
Simplify it.
Reviewed by: alc, kib
MFC after: 3 weeks
Tested by: pho (previous revisions)
Differential Revision: https://reviews.freebsd.org/D35232
(cherry picked from commit 04e86ae357b21fce238a90f31198b25975d0f479)
---
sys/dev/iommu/busdma_iommu.c | 34 +++++++++-------------------------
1 file changed, 9 insertions(+), 25 deletions(-)
diff --git a/sys/dev/iommu/busdma_iommu.c b/sys/dev/iommu/busdma_iommu.c
index 02ac5845bdcc..89e5e1bcff39 100644
--- a/sys/dev/iommu/busdma_iommu.c
+++ b/sys/dev/iommu/busdma_iommu.c
@@ -563,15 +563,16 @@ iommu_bus_dmamap_load_something1(struct bus_dma_tag_iommu
*tag,
struct iommu_ctx *ctx;
struct iommu_domain *domain;
struct iommu_map_entry *entry;
- iommu_gaddr_t size;
bus_size_t buflen1;
- int error, idx, gas_flags, seg;
+ int error, e_flags, idx, gas_flags, seg;
KASSERT(offset < IOMMU_PAGE_SIZE, ("offset %d", offset));
if (segs == NULL)
segs = tag->segments;
ctx = tag->ctx;
domain = ctx->domain;
+ e_flags = IOMMU_MAP_ENTRY_READ |
+ ((flags & BUS_DMA_NOWRITE) == 0 ? IOMMU_MAP_ENTRY_WRITE : 0);
seg = *segp;
error = 0;
idx = 0;
@@ -583,7 +584,6 @@ iommu_bus_dmamap_load_something1(struct bus_dma_tag_iommu
*tag,
}
buflen1 = buflen > tag->common.maxsegsz ?
tag->common.maxsegsz : buflen;
- size = round_page(offset + buflen1);
/*
* (Too) optimistically allow split if there are more
@@ -593,30 +593,14 @@ iommu_bus_dmamap_load_something1(struct bus_dma_tag_iommu
*tag,
if (seg + 1 < tag->common.nsegments)
gas_flags |= IOMMU_MF_CANSPLIT;
- error = iommu_map(domain, &tag->common, size, offset,
- IOMMU_MAP_ENTRY_READ |
- ((flags & BUS_DMA_NOWRITE) == 0 ? IOMMU_MAP_ENTRY_WRITE :
0),
- gas_flags, ma + idx, &entry);
+ error = iommu_map(domain, &tag->common,
+ round_page(offset + buflen1),
+ offset, e_flags, gas_flags, ma + idx, &entry);
if (error != 0)
break;
- if ((gas_flags & IOMMU_MF_CANSPLIT) != 0) {
- KASSERT(size >= entry->end - entry->start,
- ("split increased entry size %jx %jx %jx",
- (uintmax_t)size, (uintmax_t)entry->start,
- (uintmax_t)entry->end));
- size = entry->end - entry->start;
- if (buflen1 > size)
- buflen1 = size;
- } else {
- KASSERT(entry->end - entry->start == size,
- ("no split allowed %jx %jx %jx",
- (uintmax_t)size, (uintmax_t)entry->start,
- (uintmax_t)entry->end));
- }
- if (offset + buflen1 > size)
- buflen1 = size - offset;
- if (buflen1 > tag->common.maxsegsz)
- buflen1 = tag->common.maxsegsz;
+ /* Update buflen1 in case buffer split. */
+ if (buflen1 > entry->end - entry->start - offset)
+ buflen1 = entry->end - entry->start - offset;
KASSERT(((entry->start + offset) & (tag->common.alignment - 1))
== 0,
