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x86 busdma_bounce: use malloc_domainset_aligned(9).

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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
This commit is contained in:
Konstantin Belousov 2021-01-14 06:02:21 +02:00
parent 3b15beb30b
commit f3ea417f96
1 changed files with 10 additions and 10 deletions
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20
sys/x86/x86/busdma_bounce.c
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@ -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)) &&