On 20.08.2026 20:04, David Hildenbrand (Arm) wrote:
/* This part must be outside protection */> diff --git a/mm/cma.c b/mm/cma.c index a10ea37a261d..1e1ebae79090 100644 --- a/mm/cma.c +++ b/mm/cma.c @@ -936,6 +936,141 @@ struct page *cma_alloc_frozen_compound(struct cma *cma, unsigned int order) return __cma_alloc_frozen(cma, 1 << order, order, gfp); } +static int cma_range_alloc_at(struct cma *cma, struct cma_memrange *cmr,
- unsigned long offset, unsigned long count,
- struct page **pagep, gfp_t gfp)
+{
- struct page *page = NULL;
- unsigned long pfn;
- int ret = -EBUSY;
- spin_lock_irq(&cma->lock);
- /*
- If the request is larger than the available number of pages, stop
- right away.
- */
- if (count > cma->available_count)
- goto unlock;
- ret = bitmap_allocate(cmr->bitmap, offset, count);
- if (ret < 0)
- goto unlock;
- pfn = cmr->base_pfn + offset;
- page = pfn_to_page(pfn);
- /*
- Do not hand out page ranges that are not contiguous, so
- callers can just iterate the pages without having to worry
- about these corner cases.
- */
- if (!page_range_contiguous(page, count)) {
- pr_warn_ratelimited("%s: %s: skipping non-contiguous area [0x%lx-0x%lx]",
- __func__, cma->name, pfn, pfn + count - 1);
- ret = -EBUSY;
- goto clear;
- }
- cma->available_count -= count;
- /*
- It's safe to drop the lock here. We've marked this region for
- our exclusive use. If the migration fails we will take the
- lock again and unmark it.
- */
- spin_unlock_irq(&cma->lock);
- mutex_lock(&cma->alloc_mutex);
- ret = alloc_contig_frozen_range(pfn, pfn + count, ACR_FLAGS_CMA, gfp);
- mutex_unlock(&cma->alloc_mutex);
There is quite some code duplication with cma_range_alloc(). Please try harder to factor common code out and reuse it.
...
Also here, way too much code duplication with __cma_alloc_frozen().
There must be a better way :)
Maybe the existing 'alloc' functions could call 'alloc_at' variant internally
(with locks adjusted and moved out).
(I really prefer this direction of the patch set)
Definitely, I also like this approach much more than previous attempt with
'dynamically' instantiated cma regions.
Best regards