The branch main has been updated by kib:
URL:
https://cgit.FreeBSD.org/src/commit/?id=f3ea417f96b011a7eb4f43e3142e572833287ef4
commit f3ea417f96b011a7eb4f43e3142e572833287ef4
Author: Konstantin Belousov <k...@freebsd.org>
AuthorDate: 2021-01-14 04:02:21 +0000
Commit: Konstantin Belousov <k...@freebsd.org>
CommitDate: 2021-01-17 17:29:05 +0000
x86 busdma_bounce: use malloc_domainset_aligned(9).
This stops busdma bounce making assumptions about alignment of malloc(9)
results, which are no longer true.
Also add assert that the result of malloc_aligned() fits into single
page, which is the assumption of the code.
Reported by: dim
Reviewed by: andrew, jah, markj
Tested by: pho
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D28147
---
sys/x86/x86/busdma_bounce.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/sys/x86/x86/busdma_bounce.c b/sys/x86/x86/busdma_bounce.c
index 65fbbb7ec1a4..75fdf4143b9b 100644
--- a/sys/x86/x86/busdma_bounce.c
+++ b/sys/x86/x86/busdma_bounce.c
@@ -433,9 +433,9 @@ bounce_bus_dmamem_alloc(bus_dma_tag_t dmat, void **vaddr,
int flags,
/*
* Allocate the buffer from the malloc(9) allocator if...
- * - It's small enough to fit into a single power of two sized bucket.
- * - The alignment is less than or equal to the maximum size
+ * - It's small enough to fit into a single page.
* - The low address requirement is fulfilled.
+ * - Default cache attributes are requested (WB).
* else allocate non-contiguous pages if...
* - The page count that could get allocated doesn't exceed
* nsegments also when the maximum segment size is less
@@ -445,19 +445,19 @@ bounce_bus_dmamem_alloc(bus_dma_tag_t dmat, void **vaddr,
int flags,
* else allocate a block of contiguous pages because one or more of the
* constraints is something that only the contig allocator can fulfill.
*
- * NOTE: The (dmat->common.alignment <= dmat->maxsize) check
- * below is just a quick hack. The exact alignment guarantees
- * of malloc(9) need to be nailed down, and the code below
- * should be rewritten to take that into account.
- *
- * In the meantime warn the user if malloc gets it wrong.
+ * Warn the user if malloc gets it wrong.
*/
if (dmat->common.maxsize <= PAGE_SIZE &&
- dmat->common.alignment <= dmat->common.maxsize &&
dmat->common.lowaddr >= ptoa((vm_paddr_t)Maxmem) &&
attr == VM_MEMATTR_DEFAULT) {
- *vaddr = malloc_domainset(dmat->common.maxsize, M_DEVBUF,
+ *vaddr = malloc_domainset_aligned(dmat->common.maxsize,
+ dmat->common.alignment, M_DEVBUF,
DOMAINSET_PREF(dmat->common.domain), mflags);
+ KASSERT(*vaddr == NULL || ((uintptr_t)*vaddr & PAGE_MASK) +
+ dmat->common.maxsize <= PAGE_SIZE,
+ ("bounce_bus_dmamem_alloc: multi-page alloc %p maxsize "
+ "%#jx align %#jx", *vaddr, (uintmax_t)dmat->common.maxsize,
+ (uintmax_t)dmat->common.alignment));
} else if (dmat->common.nsegments >=
howmany(dmat->common.maxsize, MIN(dmat->common.maxsegsz,
PAGE_SIZE)) &&
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