Ideally, cma_release could be called from any context. However, that is not possible because a mutex is used to protect the per-area bitmap. Change the bitmap to an irq safe spinlock.
Signed-off-by: Mike Kravetz <[email protected]> --- mm/cma.c | 20 +++++++++++--------- mm/cma.h | 2 +- mm/cma_debug.c | 10 ++++++---- 3 files changed, 18 insertions(+), 14 deletions(-) diff --git a/mm/cma.c b/mm/cma.c index b2393b892d3b..80875fd4487b 100644 --- a/mm/cma.c +++ b/mm/cma.c @@ -24,7 +24,6 @@ #include <linux/memblock.h> #include <linux/err.h> #include <linux/mm.h> -#include <linux/mutex.h> #include <linux/sizes.h> #include <linux/slab.h> #include <linux/log2.h> @@ -83,13 +82,14 @@ static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, unsigned int count) { unsigned long bitmap_no, bitmap_count; + unsigned long flags; bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit; bitmap_count = cma_bitmap_pages_to_bits(cma, count); - mutex_lock(&cma->lock); + spin_lock_irqsave(&cma->lock, flags); bitmap_clear(cma->bitmap, bitmap_no, bitmap_count); - mutex_unlock(&cma->lock); + spin_unlock_irqrestore(&cma->lock, flags); } static void __init cma_activate_area(struct cma *cma) @@ -118,7 +118,7 @@ static void __init cma_activate_area(struct cma *cma) pfn += pageblock_nr_pages) init_cma_reserved_pageblock(pfn_to_page(pfn)); - mutex_init(&cma->lock); + spin_lock_init(&cma->lock); #ifdef CONFIG_CMA_DEBUGFS INIT_HLIST_HEAD(&cma->mem_head); @@ -391,8 +391,9 @@ static void cma_debug_show_areas(struct cma *cma) unsigned long start = 0; unsigned long nr_part, nr_total = 0; unsigned long nbits = cma_bitmap_maxno(cma); + unsigned long flags; - mutex_lock(&cma->lock); + spin_lock_irqsave(&cma->lock, flags); pr_info("number of available pages: "); for (;;) { next_zero_bit = find_next_zero_bit(cma->bitmap, nbits, start); @@ -407,7 +408,7 @@ static void cma_debug_show_areas(struct cma *cma) start = next_zero_bit + nr_zero; } pr_cont("=> %lu free of %lu total pages\n", nr_total, cma->count); - mutex_unlock(&cma->lock); + spin_unlock_irqrestore(&cma->lock, flags); } #else static inline void cma_debug_show_areas(struct cma *cma) { } @@ -430,6 +431,7 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, unsigned long pfn = -1; unsigned long start = 0; unsigned long bitmap_maxno, bitmap_no, bitmap_count; + unsigned long flags; size_t i; struct page *page = NULL; int ret = -ENOMEM; @@ -454,12 +456,12 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, goto out; for (;;) { - mutex_lock(&cma->lock); + spin_lock_irqsave(&cma->lock, flags); bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap, bitmap_maxno, start, bitmap_count, mask, offset); if (bitmap_no >= bitmap_maxno) { - mutex_unlock(&cma->lock); + spin_unlock_irqrestore(&cma->lock, flags); break; } bitmap_set(cma->bitmap, bitmap_no, bitmap_count); @@ -468,7 +470,7 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, * our exclusive use. If the migration fails we will take the * lock again and unmark it. */ - mutex_unlock(&cma->lock); + spin_unlock_irqrestore(&cma->lock, flags); pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit); ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, diff --git a/mm/cma.h b/mm/cma.h index 68ffad4e430d..2c775877eae2 100644 --- a/mm/cma.h +++ b/mm/cma.h @@ -15,7 +15,7 @@ struct cma { unsigned long count; unsigned long *bitmap; unsigned int order_per_bit; /* Order of pages represented by one bit */ - struct mutex lock; + spinlock_t lock; #ifdef CONFIG_CMA_DEBUGFS struct hlist_head mem_head; spinlock_t mem_head_lock; diff --git a/mm/cma_debug.c b/mm/cma_debug.c index d5bf8aa34fdc..6379cfbfd568 100644 --- a/mm/cma_debug.c +++ b/mm/cma_debug.c @@ -35,11 +35,12 @@ static int cma_used_get(void *data, u64 *val) { struct cma *cma = data; unsigned long used; + unsigned long flags; - mutex_lock(&cma->lock); + spin_lock_irqsave(&cma->lock, flags); /* pages counter is smaller than sizeof(int) */ used = bitmap_weight(cma->bitmap, (int)cma_bitmap_maxno(cma)); - mutex_unlock(&cma->lock); + spin_unlock_irqrestore(&cma->lock, flags); *val = (u64)used << cma->order_per_bit; return 0; @@ -52,8 +53,9 @@ static int cma_maxchunk_get(void *data, u64 *val) unsigned long maxchunk = 0; unsigned long start, end = 0; unsigned long bitmap_maxno = cma_bitmap_maxno(cma); + unsigned long flags; - mutex_lock(&cma->lock); + spin_lock_irqsave(&cma->lock, flags); for (;;) { start = find_next_zero_bit(cma->bitmap, bitmap_maxno, end); if (start >= bitmap_maxno) @@ -61,7 +63,7 @@ static int cma_maxchunk_get(void *data, u64 *val) end = find_next_bit(cma->bitmap, bitmap_maxno, start); maxchunk = max(end - start, maxchunk); } - mutex_unlock(&cma->lock); + spin_unlock_irqrestore(&cma->lock, flags); *val = (u64)maxchunk << cma->order_per_bit; return 0; -- 2.30.2
