Remove unnecessary WITNESS check in x86 bounce_bus_dmamem_alloc()

[jah]

Summary

When I did some header cleanup in r320528, I copy-pasted some sketchy WITNESS
checks from the prior busdma wrappers. Two of these were removed in r346351
and r346851, but one remains in bounce_bus_dmamem_alloc(). This check could
be constrained to only apply if (flags & BUS_DMA_NOWAIT), but it's cleaner to
simply remove it and rely on the checks already present in the sleepable
allocation paths used by this function.

Noticed by: cem

[jah]

Remove another unnecessary WITNESS check in the shared x86 bus_dma_tag_create()
implementation. Both DMAR and bounce implementations use
common_bus_dma_tag_create(), which allocates the tag with M_NOWAIT.

[cem]

Thanks!

sys/x86/x86/busdma_bounce.c

410–411 ↗

(On Diff #72581)

This one might be reasonable without BUS_DMA_NOWAIT, since we will allocate sleepable in that context. But I suppose we'll just get the exact same warning from malloc(9), so maybe this was redundant?

493 ↗

(On Diff #72581)

Might fix "allociated" if you're doing typos on this line

[jah]

sys/x86/x86/busdma_bounce.c

410–411 ↗

(On Diff #72581)

Yeah, UMA directly issues the same WITNESS_WARN for sleepable allocations, and kmem_alloc_contig() will go through msleep() if it needs to wait for pages.

493 ↗

(On Diff #72581)

Ha! My brain just substituted "associated" when I read that.

[cem]

sys/x86/x86/busdma_bounce.c

410–411 ↗

(On Diff #72581)

Excellent! :-)

[jah]

Fix another typo

[jah]

sys/x86/x86/busdma_bounce.c

410–411 ↗

(On Diff #72581)

Even better, the !M_NOWAIT case of kmem_alloc_* gets a WITNESS check through vmem_alloc(), which will catch abusers even if backing pages are readily available. Otherwise I was going to add one in kmem_alloc_contig_pages().