[PATCH 1/2] mm: cma: split out in_cma check to separate function
From: Michal Nazarewicz <hidden>
Date: 2016-02-19 13:46:44
Also in:
linux-mm, lkml
On Fri, Feb 19 2016, Rabin Vincent wrote:
quoted hunk ↗ jump to hunk
Split out the logic in cma_release() which checks if the page is in the contiguous area to a new function which can be called separately. ARM will use this. Signed-off-by: Rabin Vincent <redacted> --- include/linux/cma.h | 12 ++++++++++++ mm/cma.c | 27 +++++++++++++++++++-------- 2 files changed, 31 insertions(+), 8 deletions(-)diff --git a/include/linux/cma.h b/include/linux/cma.h index 29f9e77..6e7fd2d 100644 --- a/include/linux/cma.h +++ b/include/linux/cma.h@@ -27,5 +27,17 @@ extern int cma_init_reserved_mem(phys_addr_t base, phys_addr_t size, unsigned int order_per_bit, struct cma **res_cma); extern struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align); + extern bool cma_release(struct cma *cma, const struct page *pages, unsigned int count); +#ifdef CONFIG_CMA +extern bool in_cma(struct cma *cma, const struct page *pages, + unsigned int count); +#else +static inline bool in_cma(struct cma *cma, const struct page *pages, + unsigned int count) +{ + return false; +} +#endif + #endifdiff --git a/mm/cma.c b/mm/cma.c index ea506eb..55cda16 100644 --- a/mm/cma.c +++ b/mm/cma.c@@ -426,6 +426,23 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align) return page; } +bool in_cma(struct cma *cma, const struct page *pages, unsigned int count)
Should it instead take pfn as an argument instead of a page? IIRC
page_to_pfn may be expensive on some architectures and with this patch,
cma_release will call it twice.
Or maybe in_cma could return a pfn, something like (error checking
stripped):
unsigned long pfn in_cma(struct cma *cma, const struct page *page,
unsgined count)
{
unsigned long pfn = page_to_pfn(page);
if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
return 0;
VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
return pfn;
}
Is pfn == 0 guaranteed to be invalid?
quoted hunk ↗ jump to hunk
+{ + unsigned long pfn; + + if (!cma || !pages) + return false; + + pfn = page_to_pfn(pages); + + if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count) + return false; + + VM_BUG_ON(pfn + count > cma->base_pfn + cma->count); + + return true; +} + /** * cma_release() - release allocated pages * @cma: Contiguous memory region for which the allocation is performed.@@ -440,18 +457,12 @@ bool cma_release(struct cma *cma, const struct page *pages, unsigned int count) { unsigned long pfn; - if (!cma || !pages) - return false; - pr_debug("%s(page %p)\n", __func__, (void *)pages); - pfn = page_to_pfn(pages); - - if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count) + if (!in_cma(cma, pages, count)) return false; - VM_BUG_ON(pfn + count > cma->base_pfn + cma->count); - + pfn = page_to_pfn(pages); free_contig_range(pfn, count); cma_clear_bitmap(cma, pfn, count); trace_cma_release(pfn, pages, count);-- 2.7.0
-- Best regards Liege of Serenely Enlightened Majesty of Computer Science, ??? ?mina86? ?????? [off-list ref] <xmpp:mina86@jabber.org>