mm: cma: improve pr_debug log in cma_release()

It is required to print 'count' of pages, along with the pages, passed to
cma_release to debug the cases of mismatched count value passed between
cma_alloc() and cma_release() from a code path.

As an example, consider the below scenario:

1) CMA pool size is 4MB and

2) User doing the erroneous step of allocating 2 pages but freeing 1
   page in a loop from this CMA pool.  The step 2 causes cma_alloc() to
   return NULL at one point of time because of -ENOMEM condition.

And the current pr_debug logs is not giving the info about these types of
allocation patterns because of count value not being printed in
cma_release().

We are printing the count value in the trace logs, just extend the same to
pr_debug logs too.

[akpm@linux-foundation.org: fix printk warning]

Link: https://lkml.kernel.org/r/1606318341-29521-1-git-send-email-charante@codeaurora.org
Signed-off-by: Charan Teja Reddy <charante@codeaurora.org>
Reviewed-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Origin: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=b8ca396f984295ba09f25f6982f9abd0bb7f5a29
Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>
Change-Id: Ic44cb49df247f690145a2d9dc8279aa94de4205f

diff --git a/mm/cma.c b/mm/cma.c
index 7f415d7..a751ed4 100644 (file)
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -512,7 +512,7 @@ bool cma_release(struct cma *cma, const struct page *pages, unsigned int count)
        if (!cma || !pages)
                return false;
 
-       pr_debug("%s(page %p)\n", __func__, (void *)pages);
+       pr_debug("%s(page %p, count %u)\n", __func__, (void *)pages, count);
 
        pfn = page_to_pfn(pages);