mm/cma: don't treat bad input arguments for cma_alloc() as its failure

Invalid cma_alloc() input scenarios - including excess allocation request
should neither be counted as CMA_ALLOC_FAIL nor 'cma->nr_pages_failed' be
updated when applicable with CONFIG_CMA_SYSFS. This also drops 'out' jump
label which has become redundant.

Link: https://lkml.kernel.org/r/20240201023714.3871061-1-anshuman.khandual@arm.comSigned-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/cma.c

@@ -441,13 +441,13 @@ struct page *cma_alloc(struct cma *cma, unsigned long count,
 	trace_cma_alloc_start(name, count, align);
 
 	if (!cma || !cma->count || !cma->bitmap)
-		goto out;
+		return page;
 
 	pr_debug("%s(cma %p, name: %s, count %lu, align %d)\n", __func__,
 		(void *)cma, cma->name, count, align);
 
 	if (!count)
-		goto out;
+		return page;
 
 	mask = cma_bitmap_aligned_mask(cma, align);
 	offset = cma_bitmap_aligned_offset(cma, align);
@@ -455,7 +455,7 @@ struct page *cma_alloc(struct cma *cma, unsigned long count,
 	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
 
 	if (bitmap_count > bitmap_maxno)
-		goto out;
+		return page;
 
 	for (;;) {
 		spin_lock_irq(&cma->lock);
@@ -514,15 +514,13 @@ struct page *cma_alloc(struct cma *cma, unsigned long count,
 	}
 
 	pr_debug("%s(): returned %p\n", __func__, page);
-out:
 	trace_cma_alloc_finish(name, pfn, page, count, align, ret);
 	if (page) {
 		count_vm_event(CMA_ALLOC_SUCCESS);
 		cma_sysfs_account_success_pages(cma, count);
 	} else {
 		count_vm_event(CMA_ALLOC_FAIL);
-		if (cma)
-			cma_sysfs_account_fail_pages(cma, count);
+		cma_sysfs_account_fail_pages(cma, count);
 	}
 
 	return page;