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* [PATCH v2 0/6] zram clean up
@ 2017-04-13  2:59 Minchan Kim
  2017-04-13  2:59 ` [PATCH v2 1/6] zram: handle multiple pages attached bio's bvec Minchan Kim
                   ` (5 more replies)
  0 siblings, 6 replies; 9+ messages in thread
From: Minchan Kim @ 2017-04-13  2:59 UTC (permalink / raw)
  To: Andrew Morton; +Cc: kernel-team, linux-kernel, Minchan Kim

This patchset aims zram clean-up.

[1] clean up multiple pages's bvec handling.
[2] clean up partial IO handling
[3-6] clean up zram via using accessor and removing pointless structure.

With [2-6] applied, we can get a few hundred bytes as well as huge
readibility enhance.

This patchset is based on 2017-04-11-15-23 + recent ppc64 fixes[1]

[1] https://lkml.org/lkml/2017/4/12/924

* from v1
  * more clean up - Sergey
  * Fix zram_reset metadata overwrite - Sergey
  * Fix bvec handling in __zram_make_request
  * use zram_free_page in reset rather than zs_free

x86: 708 byte save

    add/remove: 1/1 grow/shrink: 0/11 up/down: 478/-1186 (-708)
    function                                     old     new   delta
    zram_special_page_read                         -     478    +478
    zram_reset_device                            317     314      -3
    mem_used_max_store                           131     128      -3
    compact_store                                 96      93      -3
    mm_stat_show                                 203     197      -6
    zram_add                                     719     712      -7
    zram_slot_free_notify                        229     214     -15
    zram_make_request                            819     803     -16
    zram_meta_free                               128     111     -17
    zram_free_page                               180     151     -29
    disksize_store                               432     361     -71
    zram_decompress_page.isra                    504       -    -504
    zram_bvec_rw                                2592    2080    -512
    Total: Before=25350773, After=25350065, chg -0.00%
    
ppc64: 231 byte save
    
    add/remove: 2/0 grow/shrink: 1/9 up/down: 681/-912 (-231)
    function                                     old     new   delta
    zram_special_page_read                         -     480    +480
    zram_slot_lock                                 -     200    +200
    vermagic                                      39      40      +1
    mm_stat_show                                 256     248      -8
    zram_meta_free                               200     184     -16
    zram_add                                     944     912     -32
    zram_free_page                               348     308     -40
    disksize_store                               572     492     -80
    zram_decompress_page                         664     564    -100
    zram_slot_free_notify                        292     160    -132
    zram_make_request                           1132    1000    -132
    zram_bvec_rw                                2768    2396    -372
    Total: Before=17565825, After=17565594, chg -0.00%

Minchan Kim (6):
  zram: handle multiple pages attached bio's bvec
  zram: partial IO refactoring
  zram: use zram_slot_lock instead of raw bit_spin_lock op
  zram: remove zram_meta structure
  zram: introduce zram data accessor
  zram: use zram_free_page instead of open-coded

 drivers/block/zram/zram_drv.c | 567 +++++++++++++++++++++---------------------
 drivers/block/zram/zram_drv.h |   6 +-
 2 files changed, 281 insertions(+), 292 deletions(-)

-- 
2.7.4

^ permalink raw reply	[flat|nested] 9+ messages in thread
* [PATCH v2 1/6] zram: handle multiple pages attached bio's bvec
  2017-04-13  2:59 [PATCH v2 0/6] zram clean up Minchan Kim
@ 2017-04-13  2:59 ` Minchan Kim
  2017-04-13  7:15   ` Johannes Thumshirn
  2017-04-13  2:59 ` [PATCH v2 2/6] zram: partial IO refactoring Minchan Kim
                   ` (4 subsequent siblings)
  5 siblings, 1 reply; 9+ messages in thread
From: Minchan Kim @ 2017-04-13  2:59 UTC (permalink / raw)
  To: Andrew Morton
  Cc: kernel-team, linux-kernel, Minchan Kim, Hannes Reinecke,
	Johannes Thumshirn, Sergey Senozhatsky

Johannes Thumshirn reported system goes the panic when using NVMe over
Fabrics loopback target with zram.

The reason is zram expects each bvec in bio contains a single page
but nvme can attach a huge bulk of pages attached to the bio's bvec
so that zram's index arithmetic could be wrong so that out-of-bound
access makes system panic.

[1] in mainline solved solved the problem by limiting max_sectors with
SECTORS_PER_PAGE but it makes zram slow because bio should split with
each pages so this patch makes zram aware of multiple pages in a bvec
so it could solve without any regression(ie, bio split).

[1] 0bc315381fe9, zram: set physical queue limits to avoid array out of
    bounds accesses

* from v1
  * Do not exceed page boundary when set up bv.bv_len in make_request
  * change "remained" variable name with "unwritten"

Cc: Hannes Reinecke <hare@suse.com>
Reported-by: Johannes Thumshirn <jthumshirn@suse.de>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
 drivers/block/zram/zram_drv.c | 38 +++++++++++---------------------------
 1 file changed, 11 insertions(+), 27 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 11cc8767af99..9c3f862b72f4 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -137,8 +137,7 @@ static inline bool valid_io_request(struct zram *zram,
 
 static void update_position(u32 *index, int *offset, struct bio_vec *bvec)
 {
-	if (*offset + bvec->bv_len >= PAGE_SIZE)
-		(*index)++;
+	*index  += (*offset + bvec->bv_len) / PAGE_SIZE;
 	*offset = (*offset + bvec->bv_len) % PAGE_SIZE;
 }
 
@@ -838,34 +837,21 @@ static void __zram_make_request(struct zram *zram, struct bio *bio)
 	}
 
 	bio_for_each_segment(bvec, bio, iter) {
-		int max_transfer_size = PAGE_SIZE - offset;
-
-		if (bvec.bv_len > max_transfer_size) {
-			/*
-			 * zram_bvec_rw() can only make operation on a single
-			 * zram page. Split the bio vector.
-			 */
-			struct bio_vec bv;
-
-			bv.bv_page = bvec.bv_page;
-			bv.bv_len = max_transfer_size;
-			bv.bv_offset = bvec.bv_offset;
+		struct bio_vec bv = bvec;
+		unsigned int unwritten = bvec.bv_len;
 
+		do {
+			bv.bv_len = min_t(unsigned int, PAGE_SIZE - offset,
+							unwritten);
 			if (zram_bvec_rw(zram, &bv, index, offset,
-					 op_is_write(bio_op(bio))) < 0)
+					op_is_write(bio_op(bio))) < 0)
 				goto out;
 
-			bv.bv_len = bvec.bv_len - max_transfer_size;
-			bv.bv_offset += max_transfer_size;
-			if (zram_bvec_rw(zram, &bv, index + 1, 0,
-					 op_is_write(bio_op(bio))) < 0)
-				goto out;
-		} else
-			if (zram_bvec_rw(zram, &bvec, index, offset,
-					 op_is_write(bio_op(bio))) < 0)
-				goto out;
+			bv.bv_offset += bv.bv_len;
+			unwritten -= bv.bv_len;
 
-		update_position(&index, &offset, &bvec);
+			update_position(&index, &offset, &bv);
+		} while (unwritten);
 	}
 
 	bio_endio(bio);
@@ -882,8 +868,6 @@ static blk_qc_t zram_make_request(struct request_queue *queue, struct bio *bio)
 {
 	struct zram *zram = queue->queuedata;
 
-	blk_queue_split(queue, &bio, queue->bio_split);
-
 	if (!valid_io_request(zram, bio->bi_iter.bi_sector,
 					bio->bi_iter.bi_size)) {
 		atomic64_inc(&zram->stats.invalid_io);
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 9+ messages in thread
* [PATCH v2 2/6] zram: partial IO refactoring
  2017-04-13  2:59 [PATCH v2 0/6] zram clean up Minchan Kim
  2017-04-13  2:59 ` [PATCH v2 1/6] zram: handle multiple pages attached bio's bvec Minchan Kim
@ 2017-04-13  2:59 ` Minchan Kim
  2017-04-13  2:59 ` [PATCH v2 3/6] zram: use zram_slot_lock instead of raw bit_spin_lock op Minchan Kim
                   ` (3 subsequent siblings)
  5 siblings, 0 replies; 9+ messages in thread
From: Minchan Kim @ 2017-04-13  2:59 UTC (permalink / raw)
  To: Andrew Morton; +Cc: kernel-team, linux-kernel, Minchan Kim

For architecture(PAGE_SIZE > 4K), zram have supported partial IO.
However, the mixed code for handling normal/partial IO is too mess,
error-prone to modify IO handler functions with upcoming feature
so this patch aims for cleaning up zram's IO handling functions.

Signed-off-by: Minchan Kim <minchan@kernel.org>
---
 drivers/block/zram/zram_drv.c | 337 +++++++++++++++++++++++-------------------
 1 file changed, 184 insertions(+), 153 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 9c3f862b72f4..c4445995fd13 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -45,6 +45,8 @@ static const char *default_compressor = "lzo";
 /* Module params (documentation at end) */
 static unsigned int num_devices = 1;
 
+static void zram_free_page(struct zram *zram, size_t index);
+
 static inline bool init_done(struct zram *zram)
 {
 	return zram->disksize;
@@ -98,10 +100,17 @@ static void zram_set_obj_size(struct zram_meta *meta,
 	meta->table[index].value = (flags << ZRAM_FLAG_SHIFT) | size;
 }
 
+#if PAGE_SIZE != 4096
 static inline bool is_partial_io(struct bio_vec *bvec)
 {
 	return bvec->bv_len != PAGE_SIZE;
 }
+#else
+static inline bool is_partial_io(struct bio_vec *bvec)
+{
+	return false;
+}
+#endif
 
 static void zram_revalidate_disk(struct zram *zram)
 {
@@ -191,18 +200,6 @@ static bool page_same_filled(void *ptr, unsigned long *element)
 	return true;
 }
 
-static void handle_same_page(struct bio_vec *bvec, unsigned long element)
-{
-	struct page *page = bvec->bv_page;
-	void *user_mem;
-
-	user_mem = kmap_atomic(page);
-	zram_fill_page(user_mem + bvec->bv_offset, bvec->bv_len, element);
-	kunmap_atomic(user_mem);
-
-	flush_dcache_page(page);
-}
-
 static ssize_t initstate_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
@@ -418,6 +415,53 @@ static DEVICE_ATTR_RO(io_stat);
 static DEVICE_ATTR_RO(mm_stat);
 static DEVICE_ATTR_RO(debug_stat);
 
+static bool zram_same_page_read(struct zram *zram, u32 index,
+				struct page *page,
+				unsigned int offset, unsigned int len)
+{
+	struct zram_meta *meta = zram->meta;
+
+	bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+	if (unlikely(!meta->table[index].handle) ||
+			zram_test_flag(meta, index, ZRAM_SAME)) {
+		void *mem;
+
+		bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+		mem = kmap_atomic(page);
+		zram_fill_page(mem + offset, len, meta->table[index].element);
+		kunmap_atomic(mem);
+		return true;
+	}
+	bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+
+	return false;
+}
+
+static bool zram_same_page_write(struct zram *zram, u32 index,
+					struct page *page)
+{
+	unsigned long element;
+	void *mem = kmap_atomic(page);
+
+	if (page_same_filled(mem, &element)) {
+		struct zram_meta *meta = zram->meta;
+
+		kunmap_atomic(mem);
+		/* Free memory associated with this sector now. */
+		bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+		zram_free_page(zram, index);
+		zram_set_flag(meta, index, ZRAM_SAME);
+		zram_set_element(meta, index, element);
+		bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+
+		atomic64_inc(&zram->stats.same_pages);
+		return true;
+	}
+	kunmap_atomic(mem);
+
+	return false;
+}
+
 static void zram_meta_free(struct zram_meta *meta, u64 disksize)
 {
 	size_t num_pages = disksize >> PAGE_SHIFT;
@@ -504,169 +548,103 @@ static void zram_free_page(struct zram *zram, size_t index)
 	zram_set_obj_size(meta, index, 0);
 }
 
-static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
+static int zram_decompress_page(struct zram *zram, struct page *page, u32 index)
 {
-	int ret = 0;
-	unsigned char *cmem;
-	struct zram_meta *meta = zram->meta;
+	int ret;
 	unsigned long handle;
 	unsigned int size;
+	void *src, *dst;
+	struct zram_meta *meta = zram->meta;
+
+	if (zram_same_page_read(zram, index, page, 0, PAGE_SIZE))
+		return 0;
 
 	bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
 	handle = meta->table[index].handle;
 	size = zram_get_obj_size(meta, index);
 
-	if (!handle || zram_test_flag(meta, index, ZRAM_SAME)) {
-		bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
-		zram_fill_page(mem, PAGE_SIZE, meta->table[index].element);
-		return 0;
-	}
-
-	cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_RO);
+	src = zs_map_object(meta->mem_pool, handle, ZS_MM_RO);
 	if (size == PAGE_SIZE) {
-		memcpy(mem, cmem, PAGE_SIZE);
+		dst = kmap_atomic(page);
+		memcpy(dst, src, PAGE_SIZE);
+		kunmap_atomic(dst);
+		ret = 0;
 	} else {
 		struct zcomp_strm *zstrm = zcomp_stream_get(zram->comp);
 
-		ret = zcomp_decompress(zstrm, cmem, size, mem);
+		dst = kmap_atomic(page);
+		ret = zcomp_decompress(zstrm, src, size, dst);
+		kunmap_atomic(dst);
 		zcomp_stream_put(zram->comp);
 	}
 	zs_unmap_object(meta->mem_pool, handle);
 	bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
 
 	/* Should NEVER happen. Return bio error if it does. */
-	if (unlikely(ret)) {
+	if (unlikely(ret))
 		pr_err("Decompression failed! err=%d, page=%u\n", ret, index);
-		return ret;
-	}
 
-	return 0;
+	return ret;
 }
 
 static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
-			  u32 index, int offset)
+				u32 index, int offset)
 {
 	int ret;
 	struct page *page;
-	unsigned char *user_mem, *uncmem = NULL;
-	struct zram_meta *meta = zram->meta;
-	page = bvec->bv_page;
 
-	bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
-	if (unlikely(!meta->table[index].handle) ||
-			zram_test_flag(meta, index, ZRAM_SAME)) {
-		bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
-		handle_same_page(bvec, meta->table[index].element);
-		return 0;
+	page = bvec->bv_page;
+	if (is_partial_io(bvec)) {
+		/* Use a temporary buffer to decompress the page */
+		page = alloc_page(GFP_NOIO|__GFP_HIGHMEM);
+		if (!page)
+			return -ENOMEM;
 	}
-	bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
 
-	if (is_partial_io(bvec))
-		/* Use  a temporary buffer to decompress the page */
-		uncmem = kmalloc(PAGE_SIZE, GFP_NOIO);
+	ret = zram_decompress_page(zram, page, index);
+	if (unlikely(ret))
+		goto out;
 
-	user_mem = kmap_atomic(page);
-	if (!is_partial_io(bvec))
-		uncmem = user_mem;
+	if (is_partial_io(bvec)) {
+		void *dst = kmap_atomic(bvec->bv_page);
+		void *src = kmap_atomic(page);
 
-	if (!uncmem) {
-		pr_err("Unable to allocate temp memory\n");
-		ret = -ENOMEM;
-		goto out_cleanup;
+		memcpy(dst + bvec->bv_offset, src + offset, bvec->bv_len);
+		kunmap_atomic(src);
+		kunmap_atomic(dst);
 	}
-
-	ret = zram_decompress_page(zram, uncmem, index);
-	/* Should NEVER happen. Return bio error if it does. */
-	if (unlikely(ret))
-		goto out_cleanup;
-
+out:
 	if (is_partial_io(bvec))
-		memcpy(user_mem + bvec->bv_offset, uncmem + offset,
-				bvec->bv_len);
+		__free_page(page);
 
-	flush_dcache_page(page);
-	ret = 0;
-out_cleanup:
-	kunmap_atomic(user_mem);
-	if (is_partial_io(bvec))
-		kfree(uncmem);
 	return ret;
 }
 
-static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
-			   int offset)
+static int zram_compress(struct zram *zram, struct zcomp_strm **zstrm,
+			struct page *page,
+			unsigned long *out_handle, unsigned int *out_comp_len)
 {
-	int ret = 0;
-	unsigned int clen;
+	int ret;
+	unsigned int comp_len;
+	void *src;
+	unsigned long alloced_pages;
 	unsigned long handle = 0;
-	struct page *page;
-	unsigned char *user_mem, *cmem, *src, *uncmem = NULL;
 	struct zram_meta *meta = zram->meta;
-	struct zcomp_strm *zstrm = NULL;
-	unsigned long alloced_pages;
-	unsigned long element;
-
-	page = bvec->bv_page;
-	if (is_partial_io(bvec)) {
-		/*
-		 * This is a partial IO. We need to read the full page
-		 * before to write the changes.
-		 */
-		uncmem = kmalloc(PAGE_SIZE, GFP_NOIO);
-		if (!uncmem) {
-			ret = -ENOMEM;
-			goto out;
-		}
-		ret = zram_decompress_page(zram, uncmem, index);
-		if (ret)
-			goto out;
-	}
 
 compress_again:
-	user_mem = kmap_atomic(page);
-	if (is_partial_io(bvec)) {
-		memcpy(uncmem + offset, user_mem + bvec->bv_offset,
-		       bvec->bv_len);
-		kunmap_atomic(user_mem);
-		user_mem = NULL;
-	} else {
-		uncmem = user_mem;
-	}
-
-	if (page_same_filled(uncmem, &element)) {
-		if (user_mem)
-			kunmap_atomic(user_mem);
-		/* Free memory associated with this sector now. */
-		bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
-		zram_free_page(zram, index);
-		zram_set_flag(meta, index, ZRAM_SAME);
-		zram_set_element(meta, index, element);
-		bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
-
-		atomic64_inc(&zram->stats.same_pages);
-		ret = 0;
-		goto out;
-	}
-
-	zstrm = zcomp_stream_get(zram->comp);
-	ret = zcomp_compress(zstrm, uncmem, &clen);
-	if (!is_partial_io(bvec)) {
-		kunmap_atomic(user_mem);
-		user_mem = NULL;
-		uncmem = NULL;
-	}
+	src = kmap_atomic(page);
+	ret = zcomp_compress(*zstrm, src, &comp_len);
+	kunmap_atomic(src);
 
 	if (unlikely(ret)) {
 		pr_err("Compression failed! err=%d\n", ret);
-		goto out;
+		if (handle)
+			zs_free(meta->mem_pool, handle);
+		return ret;
 	}
 
-	src = zstrm->buffer;
-	if (unlikely(clen > max_zpage_size)) {
-		clen = PAGE_SIZE;
-		if (is_partial_io(bvec))
-			src = uncmem;
-	}
+	if (unlikely(comp_len > max_zpage_size))
+		comp_len = PAGE_SIZE;
 
 	/*
 	 * handle allocation has 2 paths:
@@ -682,27 +660,21 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 	 * from the slow path and handle has already been allocated.
 	 */
 	if (!handle)
-		handle = zs_malloc(meta->mem_pool, clen,
+		handle = zs_malloc(meta->mem_pool, comp_len,
 				__GFP_KSWAPD_RECLAIM |
 				__GFP_NOWARN |
 				__GFP_HIGHMEM |
 				__GFP_MOVABLE);
 	if (!handle) {
 		zcomp_stream_put(zram->comp);
-		zstrm = NULL;
-
 		atomic64_inc(&zram->stats.writestall);
-
-		handle = zs_malloc(meta->mem_pool, clen,
+		handle = zs_malloc(meta->mem_pool, comp_len,
 				GFP_NOIO | __GFP_HIGHMEM |
 				__GFP_MOVABLE);
+		*zstrm = zcomp_stream_get(zram->comp);
 		if (handle)
 			goto compress_again;
-
-		pr_err("Error allocating memory for compressed page: %u, size=%u\n",
-			index, clen);
-		ret = -ENOMEM;
-		goto out;
+		return -ENOMEM;
 	}
 
 	alloced_pages = zs_get_total_pages(meta->mem_pool);
@@ -710,22 +682,45 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 
 	if (zram->limit_pages && alloced_pages > zram->limit_pages) {
 		zs_free(meta->mem_pool, handle);
-		ret = -ENOMEM;
-		goto out;
+		return -ENOMEM;
 	}
 
-	cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_WO);
+	*out_handle = handle;
+	*out_comp_len = comp_len;
+	return 0;
+}
 
-	if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) {
+static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)
+{
+	int ret;
+	unsigned long handle;
+	unsigned int comp_len;
+	void *src, *dst;
+	struct zcomp_strm *zstrm;
+	struct zram_meta *meta = zram->meta;
+	struct page *page = bvec->bv_page;
+
+	if (zram_same_page_write(zram, index, page))
+		return 0;
+
+	zstrm = zcomp_stream_get(zram->comp);
+	ret = zram_compress(zram, &zstrm, page, &handle, &comp_len);
+	if (ret) {
+		zcomp_stream_put(zram->comp);
+		return ret;
+	}
+
+
+	dst = zs_map_object(meta->mem_pool, handle, ZS_MM_WO);
+
+	src = zstrm->buffer;
+	if (comp_len == PAGE_SIZE)
 		src = kmap_atomic(page);
-		memcpy(cmem, src, PAGE_SIZE);
+	memcpy(dst, src, comp_len);
+	if (comp_len == PAGE_SIZE)
 		kunmap_atomic(src);
-	} else {
-		memcpy(cmem, src, clen);
-	}
 
 	zcomp_stream_put(zram->comp);
-	zstrm = NULL;
 	zs_unmap_object(meta->mem_pool, handle);
 
 	/*
@@ -734,19 +729,54 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 	 */
 	bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
 	zram_free_page(zram, index);
-
 	meta->table[index].handle = handle;
-	zram_set_obj_size(meta, index, clen);
+	zram_set_obj_size(meta, index, comp_len);
 	bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
 
 	/* Update stats */
-	atomic64_add(clen, &zram->stats.compr_data_size);
+	atomic64_add(comp_len, &zram->stats.compr_data_size);
 	atomic64_inc(&zram->stats.pages_stored);
+	return 0;
+}
+
+static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec,
+				u32 index, int offset)
+{
+	int ret;
+	struct page *page = NULL;
+	void *src;
+	struct bio_vec vec;
+
+	vec = *bvec;
+	if (is_partial_io(bvec)) {
+		void *dst;
+		/*
+		 * This is a partial IO. We need to read the full page
+		 * before to write the changes.
+		 */
+		page = alloc_page(GFP_NOIO|__GFP_HIGHMEM);
+		if (!page)
+			return -ENOMEM;
+
+		ret = zram_decompress_page(zram, page, index);
+		if (ret)
+			goto out;
+
+		src = kmap_atomic(bvec->bv_page);
+		dst = kmap_atomic(page);
+		memcpy(dst + offset, src + bvec->bv_offset, bvec->bv_len);
+		kunmap_atomic(dst);
+		kunmap_atomic(src);
+
+		vec.bv_page = page;
+		vec.bv_len = PAGE_SIZE;
+		vec.bv_offset = 0;
+	}
+
+	ret = __zram_bvec_write(zram, &vec, index);
 out:
-	if (zstrm)
-		zcomp_stream_put(zram->comp);
 	if (is_partial_io(bvec))
-		kfree(uncmem);
+		__free_page(page);
 	return ret;
 }
 
@@ -802,6 +832,7 @@ static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
 	if (!is_write) {
 		atomic64_inc(&zram->stats.num_reads);
 		ret = zram_bvec_read(zram, bvec, index, offset);
+		flush_dcache_page(bvec->bv_page);
 	} else {
 		atomic64_inc(&zram->stats.num_writes);
 		ret = zram_bvec_write(zram, bvec, index, offset);
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 9+ messages in thread
* [PATCH v2 3/6] zram: use zram_slot_lock instead of raw bit_spin_lock op
  2017-04-13  2:59 [PATCH v2 0/6] zram clean up Minchan Kim
  2017-04-13  2:59 ` [PATCH v2 1/6] zram: handle multiple pages attached bio's bvec Minchan Kim
  2017-04-13  2:59 ` [PATCH v2 2/6] zram: partial IO refactoring Minchan Kim
@ 2017-04-13  2:59 ` Minchan Kim
  2017-04-13  2:59 ` [PATCH v2 4/6] zram: remove zram_meta structure Minchan Kim
                   ` (2 subsequent siblings)
  5 siblings, 0 replies; 9+ messages in thread
From: Minchan Kim @ 2017-04-13  2:59 UTC (permalink / raw)
  To: Andrew Morton; +Cc: kernel-team, linux-kernel, Minchan Kim, Sergey Senozhatsky

With this clean-up phase, I want to use zram's wrapper function
to lock table access which is more consistent with other zram's
functions.

Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
 drivers/block/zram/zram_drv.c | 41 +++++++++++++++++++++++++++--------------
 1 file changed, 27 insertions(+), 14 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index c4445995fd13..931fe099dbc8 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -415,24 +415,38 @@ static DEVICE_ATTR_RO(io_stat);
 static DEVICE_ATTR_RO(mm_stat);
 static DEVICE_ATTR_RO(debug_stat);
 
+static void zram_slot_lock(struct zram *zram, u32 index)
+{
+	struct zram_meta *meta = zram->meta;
+
+	bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+}
+
+static void zram_slot_unlock(struct zram *zram, u32 index)
+{
+	struct zram_meta *meta = zram->meta;
+
+	bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+}
+
 static bool zram_same_page_read(struct zram *zram, u32 index,
 				struct page *page,
 				unsigned int offset, unsigned int len)
 {
 	struct zram_meta *meta = zram->meta;
 
-	bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+	zram_slot_lock(zram, index);
 	if (unlikely(!meta->table[index].handle) ||
 			zram_test_flag(meta, index, ZRAM_SAME)) {
 		void *mem;
 
-		bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+		zram_slot_unlock(zram, index);
 		mem = kmap_atomic(page);
 		zram_fill_page(mem + offset, len, meta->table[index].element);
 		kunmap_atomic(mem);
 		return true;
 	}
-	bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+	zram_slot_unlock(zram, index);
 
 	return false;
 }
@@ -448,11 +462,11 @@ static bool zram_same_page_write(struct zram *zram, u32 index,
 
 		kunmap_atomic(mem);
 		/* Free memory associated with this sector now. */
-		bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+		zram_slot_lock(zram, index);
 		zram_free_page(zram, index);
 		zram_set_flag(meta, index, ZRAM_SAME);
 		zram_set_element(meta, index, element);
-		bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+		zram_slot_unlock(zram, index);
 
 		atomic64_inc(&zram->stats.same_pages);
 		return true;
@@ -559,7 +573,7 @@ static int zram_decompress_page(struct zram *zram, struct page *page, u32 index)
 	if (zram_same_page_read(zram, index, page, 0, PAGE_SIZE))
 		return 0;
 
-	bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+	zram_slot_lock(zram, index);
 	handle = meta->table[index].handle;
 	size = zram_get_obj_size(meta, index);
 
@@ -578,7 +592,7 @@ static int zram_decompress_page(struct zram *zram, struct page *page, u32 index)
 		zcomp_stream_put(zram->comp);
 	}
 	zs_unmap_object(meta->mem_pool, handle);
-	bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+	zram_slot_unlock(zram, index);
 
 	/* Should NEVER happen. Return bio error if it does. */
 	if (unlikely(ret))
@@ -727,11 +741,11 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)
 	 * Free memory associated with this sector
 	 * before overwriting unused sectors.
 	 */
-	bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+	zram_slot_lock(zram, index);
 	zram_free_page(zram, index);
 	meta->table[index].handle = handle;
 	zram_set_obj_size(meta, index, comp_len);
-	bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+	zram_slot_unlock(zram, index);
 
 	/* Update stats */
 	atomic64_add(comp_len, &zram->stats.compr_data_size);
@@ -789,7 +803,6 @@ static void zram_bio_discard(struct zram *zram, u32 index,
 			     int offset, struct bio *bio)
 {
 	size_t n = bio->bi_iter.bi_size;
-	struct zram_meta *meta = zram->meta;
 
 	/*
 	 * zram manages data in physical block size units. Because logical block
@@ -810,9 +823,9 @@ static void zram_bio_discard(struct zram *zram, u32 index,
 	}
 
 	while (n >= PAGE_SIZE) {
-		bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+		zram_slot_lock(zram, index);
 		zram_free_page(zram, index);
-		bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+		zram_slot_unlock(zram, index);
 		atomic64_inc(&zram->stats.notify_free);
 		index++;
 		n -= PAGE_SIZE;
@@ -922,9 +935,9 @@ static void zram_slot_free_notify(struct block_device *bdev,
 	zram = bdev->bd_disk->private_data;
 	meta = zram->meta;
 
-	bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+	zram_slot_lock(zram, index);
 	zram_free_page(zram, index);
-	bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+	zram_slot_unlock(zram, index);
 	atomic64_inc(&zram->stats.notify_free);
 }
 
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 9+ messages in thread
* [PATCH v2 4/6] zram: remove zram_meta structure
  2017-04-13  2:59 [PATCH v2 0/6] zram clean up Minchan Kim
                   ` (2 preceding siblings ...)
  2017-04-13  2:59 ` [PATCH v2 3/6] zram: use zram_slot_lock instead of raw bit_spin_lock op Minchan Kim
@ 2017-04-13  2:59 ` Minchan Kim
  2017-04-13  2:59 ` [PATCH v2 5/6] zram: introduce zram data accessor Minchan Kim
  2017-04-13  2:59 ` [PATCH v2 6/6] zram: use zram_free_page instead of open-coded Minchan Kim
  5 siblings, 0 replies; 9+ messages in thread
From: Minchan Kim @ 2017-04-13  2:59 UTC (permalink / raw)
  To: Andrew Morton; +Cc: kernel-team, linux-kernel, Minchan Kim

It's redundant now. Instead, remove it and use zram structure
directly.

Signed-off-by: Minchan Kim <minchan@kernel.org>
---
 drivers/block/zram/zram_drv.c | 189 +++++++++++++++++-------------------------
 drivers/block/zram/zram_drv.h |   6 +-
 2 files changed, 78 insertions(+), 117 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 931fe099dbc8..002019a552af 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -58,46 +58,46 @@ static inline struct zram *dev_to_zram(struct device *dev)
 }
 
 /* flag operations require table entry bit_spin_lock() being held */
-static int zram_test_flag(struct zram_meta *meta, u32 index,
+static int zram_test_flag(struct zram *zram, u32 index,
 			enum zram_pageflags flag)
 {
-	return meta->table[index].value & BIT(flag);
+	return zram->table[index].value & BIT(flag);
 }
 
-static void zram_set_flag(struct zram_meta *meta, u32 index,
+static void zram_set_flag(struct zram *zram, u32 index,
 			enum zram_pageflags flag)
 {
-	meta->table[index].value |= BIT(flag);
+	zram->table[index].value |= BIT(flag);
 }
 
-static void zram_clear_flag(struct zram_meta *meta, u32 index,
+static void zram_clear_flag(struct zram *zram, u32 index,
 			enum zram_pageflags flag)
 {
-	meta->table[index].value &= ~BIT(flag);
+	zram->table[index].value &= ~BIT(flag);
 }
 
-static inline void zram_set_element(struct zram_meta *meta, u32 index,
+static inline void zram_set_element(struct zram *zram, u32 index,
 			unsigned long element)
 {
-	meta->table[index].element = element;
+	zram->table[index].element = element;
 }
 
-static inline void zram_clear_element(struct zram_meta *meta, u32 index)
+static inline void zram_clear_element(struct zram *zram, u32 index)
 {
-	meta->table[index].element = 0;
+	zram->table[index].element = 0;
 }
 
-static size_t zram_get_obj_size(struct zram_meta *meta, u32 index)
+static size_t zram_get_obj_size(struct zram *zram, u32 index)
 {
-	return meta->table[index].value & (BIT(ZRAM_FLAG_SHIFT) - 1);
+	return zram->table[index].value & (BIT(ZRAM_FLAG_SHIFT) - 1);
 }
 
-static void zram_set_obj_size(struct zram_meta *meta,
+static void zram_set_obj_size(struct zram *zram,
 					u32 index, size_t size)
 {
-	unsigned long flags = meta->table[index].value >> ZRAM_FLAG_SHIFT;
+	unsigned long flags = zram->table[index].value >> ZRAM_FLAG_SHIFT;
 
-	meta->table[index].value = (flags << ZRAM_FLAG_SHIFT) | size;
+	zram->table[index].value = (flags << ZRAM_FLAG_SHIFT) | size;
 }
 
 #if PAGE_SIZE != 4096
@@ -252,9 +252,8 @@ static ssize_t mem_used_max_store(struct device *dev,
 
 	down_read(&zram->init_lock);
 	if (init_done(zram)) {
-		struct zram_meta *meta = zram->meta;
 		atomic_long_set(&zram->stats.max_used_pages,
-				zs_get_total_pages(meta->mem_pool));
+				zs_get_total_pages(zram->mem_pool));
 	}
 	up_read(&zram->init_lock);
 
@@ -327,7 +326,6 @@ static ssize_t compact_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t len)
 {
 	struct zram *zram = dev_to_zram(dev);
-	struct zram_meta *meta;
 
 	down_read(&zram->init_lock);
 	if (!init_done(zram)) {
@@ -335,8 +333,7 @@ static ssize_t compact_store(struct device *dev,
 		return -EINVAL;
 	}
 
-	meta = zram->meta;
-	zs_compact(meta->mem_pool);
+	zs_compact(zram->mem_pool);
 	up_read(&zram->init_lock);
 
 	return len;
@@ -373,8 +370,8 @@ static ssize_t mm_stat_show(struct device *dev,
 
 	down_read(&zram->init_lock);
 	if (init_done(zram)) {
-		mem_used = zs_get_total_pages(zram->meta->mem_pool);
-		zs_pool_stats(zram->meta->mem_pool, &pool_stats);
+		mem_used = zs_get_total_pages(zram->mem_pool);
+		zs_pool_stats(zram->mem_pool, &pool_stats);
 	}
 
 	orig_size = atomic64_read(&zram->stats.pages_stored);
@@ -417,32 +414,26 @@ static DEVICE_ATTR_RO(debug_stat);
 
 static void zram_slot_lock(struct zram *zram, u32 index)
 {
-	struct zram_meta *meta = zram->meta;
-
-	bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+	bit_spin_lock(ZRAM_ACCESS, &zram->table[index].value);
 }
 
 static void zram_slot_unlock(struct zram *zram, u32 index)
 {
-	struct zram_meta *meta = zram->meta;
-
-	bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+	bit_spin_unlock(ZRAM_ACCESS, &zram->table[index].value);
 }
 
 static bool zram_same_page_read(struct zram *zram, u32 index,
 				struct page *page,
 				unsigned int offset, unsigned int len)
 {
-	struct zram_meta *meta = zram->meta;
-
 	zram_slot_lock(zram, index);
-	if (unlikely(!meta->table[index].handle) ||
-			zram_test_flag(meta, index, ZRAM_SAME)) {
+	if (unlikely(!zram->table[index].handle) ||
+			zram_test_flag(zram, index, ZRAM_SAME)) {
 		void *mem;
 
 		zram_slot_unlock(zram, index);
 		mem = kmap_atomic(page);
-		zram_fill_page(mem + offset, len, meta->table[index].element);
+		zram_fill_page(mem + offset, len, zram->table[index].element);
 		kunmap_atomic(mem);
 		return true;
 	}
@@ -458,14 +449,12 @@ static bool zram_same_page_write(struct zram *zram, u32 index,
 	void *mem = kmap_atomic(page);
 
 	if (page_same_filled(mem, &element)) {
-		struct zram_meta *meta = zram->meta;
-
 		kunmap_atomic(mem);
 		/* Free memory associated with this sector now. */
 		zram_slot_lock(zram, index);
 		zram_free_page(zram, index);
-		zram_set_flag(meta, index, ZRAM_SAME);
-		zram_set_element(meta, index, element);
+		zram_set_flag(zram, index, ZRAM_SAME);
+		zram_set_element(zram, index, element);
 		zram_slot_unlock(zram, index);
 
 		atomic64_inc(&zram->stats.same_pages);
@@ -476,56 +465,44 @@ static bool zram_same_page_write(struct zram *zram, u32 index,
 	return false;
 }
 
-static void zram_meta_free(struct zram_meta *meta, u64 disksize)
+static void zram_meta_free(struct zram *zram, u64 disksize)
 {
 	size_t num_pages = disksize >> PAGE_SHIFT;
 	size_t index;
 
 	/* Free all pages that are still in this zram device */
 	for (index = 0; index < num_pages; index++) {
-		unsigned long handle = meta->table[index].handle;
+		unsigned long handle = zram->table[index].handle;
 		/*
 		 * No memory is allocated for same element filled pages.
 		 * Simply clear same page flag.
 		 */
-		if (!handle || zram_test_flag(meta, index, ZRAM_SAME))
+		if (!handle || zram_test_flag(zram, index, ZRAM_SAME))
 			continue;
 
-		zs_free(meta->mem_pool, handle);
+		zs_free(zram->mem_pool, handle);
 	}
 
-	zs_destroy_pool(meta->mem_pool);
-	vfree(meta->table);
-	kfree(meta);
+	zs_destroy_pool(zram->mem_pool);
+	vfree(zram->table);
 }
 
-static struct zram_meta *zram_meta_alloc(char *pool_name, u64 disksize)
+static bool zram_meta_alloc(struct zram *zram, u64 disksize)
 {
 	size_t num_pages;
-	struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL);
-
-	if (!meta)
-		return NULL;
 
 	num_pages = disksize >> PAGE_SHIFT;
-	meta->table = vzalloc(num_pages * sizeof(*meta->table));
-	if (!meta->table) {
-		pr_err("Error allocating zram address table\n");
-		goto out_error;
-	}
+	zram->table = vzalloc(num_pages * sizeof(*zram->table));
+	if (!zram->table)
+		return false;
 
-	meta->mem_pool = zs_create_pool(pool_name);
-	if (!meta->mem_pool) {
-		pr_err("Error creating memory pool\n");
-		goto out_error;
+	zram->mem_pool = zs_create_pool(zram->disk->disk_name);
+	if (!zram->mem_pool) {
+		vfree(zram->table);
+		return false;
 	}
 
-	return meta;
-
-out_error:
-	vfree(meta->table);
-	kfree(meta);
-	return NULL;
+	return true;
 }
 
 /*
@@ -535,16 +512,15 @@ static struct zram_meta *zram_meta_alloc(char *pool_name, u64 disksize)
  */
 static void zram_free_page(struct zram *zram, size_t index)
 {
-	struct zram_meta *meta = zram->meta;
-	unsigned long handle = meta->table[index].handle;
+	unsigned long handle = zram->table[index].handle;
 
 	/*
 	 * No memory is allocated for same element filled pages.
 	 * Simply clear same page flag.
 	 */
-	if (zram_test_flag(meta, index, ZRAM_SAME)) {
-		zram_clear_flag(meta, index, ZRAM_SAME);
-		zram_clear_element(meta, index);
+	if (zram_test_flag(zram, index, ZRAM_SAME)) {
+		zram_clear_flag(zram, index, ZRAM_SAME);
+		zram_clear_element(zram, index);
 		atomic64_dec(&zram->stats.same_pages);
 		return;
 	}
@@ -552,14 +528,14 @@ static void zram_free_page(struct zram *zram, size_t index)
 	if (!handle)
 		return;
 
-	zs_free(meta->mem_pool, handle);
+	zs_free(zram->mem_pool, handle);
 
-	atomic64_sub(zram_get_obj_size(meta, index),
+	atomic64_sub(zram_get_obj_size(zram, index),
 			&zram->stats.compr_data_size);
 	atomic64_dec(&zram->stats.pages_stored);
 
-	meta->table[index].handle = 0;
-	zram_set_obj_size(meta, index, 0);
+	zram->table[index].handle = 0;
+	zram_set_obj_size(zram, index, 0);
 }
 
 static int zram_decompress_page(struct zram *zram, struct page *page, u32 index)
@@ -568,16 +544,15 @@ static int zram_decompress_page(struct zram *zram, struct page *page, u32 index)
 	unsigned long handle;
 	unsigned int size;
 	void *src, *dst;
-	struct zram_meta *meta = zram->meta;
 
 	if (zram_same_page_read(zram, index, page, 0, PAGE_SIZE))
 		return 0;
 
 	zram_slot_lock(zram, index);
-	handle = meta->table[index].handle;
-	size = zram_get_obj_size(meta, index);
+	handle = zram->table[index].handle;
+	size = zram_get_obj_size(zram, index);
 
-	src = zs_map_object(meta->mem_pool, handle, ZS_MM_RO);
+	src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO);
 	if (size == PAGE_SIZE) {
 		dst = kmap_atomic(page);
 		memcpy(dst, src, PAGE_SIZE);
@@ -591,7 +566,7 @@ static int zram_decompress_page(struct zram *zram, struct page *page, u32 index)
 		kunmap_atomic(dst);
 		zcomp_stream_put(zram->comp);
 	}
-	zs_unmap_object(meta->mem_pool, handle);
+	zs_unmap_object(zram->mem_pool, handle);
 	zram_slot_unlock(zram, index);
 
 	/* Should NEVER happen. Return bio error if it does. */
@@ -643,7 +618,6 @@ static int zram_compress(struct zram *zram, struct zcomp_strm **zstrm,
 	void *src;
 	unsigned long alloced_pages;
 	unsigned long handle = 0;
-	struct zram_meta *meta = zram->meta;
 
 compress_again:
 	src = kmap_atomic(page);
@@ -653,7 +627,7 @@ static int zram_compress(struct zram *zram, struct zcomp_strm **zstrm,
 	if (unlikely(ret)) {
 		pr_err("Compression failed! err=%d\n", ret);
 		if (handle)
-			zs_free(meta->mem_pool, handle);
+			zs_free(zram->mem_pool, handle);
 		return ret;
 	}
 
@@ -674,7 +648,7 @@ static int zram_compress(struct zram *zram, struct zcomp_strm **zstrm,
 	 * from the slow path and handle has already been allocated.
 	 */
 	if (!handle)
-		handle = zs_malloc(meta->mem_pool, comp_len,
+		handle = zs_malloc(zram->mem_pool, comp_len,
 				__GFP_KSWAPD_RECLAIM |
 				__GFP_NOWARN |
 				__GFP_HIGHMEM |
@@ -682,7 +656,7 @@ static int zram_compress(struct zram *zram, struct zcomp_strm **zstrm,
 	if (!handle) {
 		zcomp_stream_put(zram->comp);
 		atomic64_inc(&zram->stats.writestall);
-		handle = zs_malloc(meta->mem_pool, comp_len,
+		handle = zs_malloc(zram->mem_pool, comp_len,
 				GFP_NOIO | __GFP_HIGHMEM |
 				__GFP_MOVABLE);
 		*zstrm = zcomp_stream_get(zram->comp);
@@ -691,11 +665,11 @@ static int zram_compress(struct zram *zram, struct zcomp_strm **zstrm,
 		return -ENOMEM;
 	}
 
-	alloced_pages = zs_get_total_pages(meta->mem_pool);
+	alloced_pages = zs_get_total_pages(zram->mem_pool);
 	update_used_max(zram, alloced_pages);
 
 	if (zram->limit_pages && alloced_pages > zram->limit_pages) {
-		zs_free(meta->mem_pool, handle);
+		zs_free(zram->mem_pool, handle);
 		return -ENOMEM;
 	}
 
@@ -711,7 +685,6 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)
 	unsigned int comp_len;
 	void *src, *dst;
 	struct zcomp_strm *zstrm;
-	struct zram_meta *meta = zram->meta;
 	struct page *page = bvec->bv_page;
 
 	if (zram_same_page_write(zram, index, page))
@@ -724,8 +697,7 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)
 		return ret;
 	}
 
-
-	dst = zs_map_object(meta->mem_pool, handle, ZS_MM_WO);
+	dst = zs_map_object(zram->mem_pool, handle, ZS_MM_WO);
 
 	src = zstrm->buffer;
 	if (comp_len == PAGE_SIZE)
@@ -735,7 +707,7 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)
 		kunmap_atomic(src);
 
 	zcomp_stream_put(zram->comp);
-	zs_unmap_object(meta->mem_pool, handle);
+	zs_unmap_object(zram->mem_pool, handle);
 
 	/*
 	 * Free memory associated with this sector
@@ -743,8 +715,8 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)
 	 */
 	zram_slot_lock(zram, index);
 	zram_free_page(zram, index);
-	meta->table[index].handle = handle;
-	zram_set_obj_size(meta, index, comp_len);
+	zram->table[index].handle = handle;
+	zram_set_obj_size(zram, index, comp_len);
 	zram_slot_unlock(zram, index);
 
 	/* Update stats */
@@ -930,10 +902,8 @@ static void zram_slot_free_notify(struct block_device *bdev,
 				unsigned long index)
 {
 	struct zram *zram;
-	struct zram_meta *meta;
 
 	zram = bdev->bd_disk->private_data;
-	meta = zram->meta;
 
 	zram_slot_lock(zram, index);
 	zram_free_page(zram, index);
@@ -981,7 +951,6 @@ static int zram_rw_page(struct block_device *bdev, sector_t sector,
 
 static void zram_reset_device(struct zram *zram)
 {
-	struct zram_meta *meta;
 	struct zcomp *comp;
 	u64 disksize;
 
@@ -994,7 +963,6 @@ static void zram_reset_device(struct zram *zram)
 		return;
 	}
 
-	meta = zram->meta;
 	comp = zram->comp;
 	disksize = zram->disksize;
 
@@ -1007,7 +975,7 @@ static void zram_reset_device(struct zram *zram)
 
 	up_write(&zram->init_lock);
 	/* I/O operation under all of CPU are done so let's free */
-	zram_meta_free(meta, disksize);
+	zram_meta_free(zram, disksize);
 	zcomp_destroy(comp);
 }
 
@@ -1016,7 +984,6 @@ static ssize_t disksize_store(struct device *dev,
 {
 	u64 disksize;
 	struct zcomp *comp;
-	struct zram_meta *meta;
 	struct zram *zram = dev_to_zram(dev);
 	int err;
 
@@ -1024,10 +991,18 @@ static ssize_t disksize_store(struct device *dev,
 	if (!disksize)
 		return -EINVAL;
 
+	down_write(&zram->init_lock);
+	if (init_done(zram)) {
+		pr_info("Cannot change disksize for initialized device\n");
+		err = -EBUSY;
+		goto out_unlock;
+	}
+
 	disksize = PAGE_ALIGN(disksize);
-	meta = zram_meta_alloc(zram->disk->disk_name, disksize);
-	if (!meta)
-		return -ENOMEM;
+	if (!zram_meta_alloc(zram, disksize)) {
+		err = -ENOMEM;
+		goto out_unlock;
+	}
 
 	comp = zcomp_create(zram->compressor);
 	if (IS_ERR(comp)) {
@@ -1037,14 +1012,6 @@ static ssize_t disksize_store(struct device *dev,
 		goto out_free_meta;
 	}
 
-	down_write(&zram->init_lock);
-	if (init_done(zram)) {
-		pr_info("Cannot change disksize for initialized device\n");
-		err = -EBUSY;
-		goto out_destroy_comp;
-	}
-
-	zram->meta = meta;
 	zram->comp = comp;
 	zram->disksize = disksize;
 	set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);
@@ -1053,11 +1020,10 @@ static ssize_t disksize_store(struct device *dev,
 
 	return len;
 
-out_destroy_comp:
-	up_write(&zram->init_lock);
-	zcomp_destroy(comp);
 out_free_meta:
-	zram_meta_free(meta, disksize);
+	zram_meta_free(zram, disksize);
+out_unlock:
+	up_write(&zram->init_lock);
 	return err;
 }
 
@@ -1246,7 +1212,6 @@ static int zram_add(void)
 		goto out_free_disk;
 	}
 	strlcpy(zram->compressor, default_compressor, sizeof(zram->compressor));
-	zram->meta = NULL;
 
 	pr_info("Added device: %s\n", zram->disk->disk_name);
 	return device_id;
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index caeff51f1571..e34e44d02e3e 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -92,13 +92,9 @@ struct zram_stats {
 	atomic64_t writestall;		/* no. of write slow paths */
 };
 
-struct zram_meta {
+struct zram {
 	struct zram_table_entry *table;
 	struct zs_pool *mem_pool;
-};
-
-struct zram {
-	struct zram_meta *meta;
 	struct zcomp *comp;
 	struct gendisk *disk;
 	/* Prevent concurrent execution of device init */
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 9+ messages in thread
* [PATCH v2 5/6] zram: introduce zram data accessor
  2017-04-13  2:59 [PATCH v2 0/6] zram clean up Minchan Kim
                   ` (3 preceding siblings ...)
  2017-04-13  2:59 ` [PATCH v2 4/6] zram: remove zram_meta structure Minchan Kim
@ 2017-04-13  2:59 ` Minchan Kim
  2017-04-13  2:59 ` [PATCH v2 6/6] zram: use zram_free_page instead of open-coded Minchan Kim
  5 siblings, 0 replies; 9+ messages in thread
From: Minchan Kim @ 2017-04-13  2:59 UTC (permalink / raw)
  To: Andrew Morton; +Cc: kernel-team, linux-kernel, Minchan Kim, Sergey Senozhatsky

With element, sometime I got confused handle and element access.
It might be my bad but I think it's time to introduce accessor
to prevent future idiot like me.
This patch is just clean-up patch so it shouldn't change any
behavior.

Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
 drivers/block/zram/zram_drv.c | 33 ++++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 11 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 002019a552af..22b249444010 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -57,6 +57,16 @@ static inline struct zram *dev_to_zram(struct device *dev)
 	return (struct zram *)dev_to_disk(dev)->private_data;
 }
 
+static unsigned long zram_get_handle(struct zram *zram, u32 index)
+{
+	return zram->table[index].handle;
+}
+
+static void zram_set_handle(struct zram *zram, u32 index, unsigned long handle)
+{
+	zram->table[index].handle = handle;
+}
+
 /* flag operations require table entry bit_spin_lock() being held */
 static int zram_test_flag(struct zram *zram, u32 index,
 			enum zram_pageflags flag)
@@ -82,9 +92,9 @@ static inline void zram_set_element(struct zram *zram, u32 index,
 	zram->table[index].element = element;
 }
 
-static inline void zram_clear_element(struct zram *zram, u32 index)
+static unsigned long zram_get_element(struct zram *zram, u32 index)
 {
-	zram->table[index].element = 0;
+	return zram->table[index].element;
 }
 
 static size_t zram_get_obj_size(struct zram *zram, u32 index)
@@ -427,13 +437,14 @@ static bool zram_same_page_read(struct zram *zram, u32 index,
 				unsigned int offset, unsigned int len)
 {
 	zram_slot_lock(zram, index);
-	if (unlikely(!zram->table[index].handle) ||
-			zram_test_flag(zram, index, ZRAM_SAME)) {
+	if (unlikely(!zram_get_handle(zram, index) ||
+			zram_test_flag(zram, index, ZRAM_SAME))) {
 		void *mem;
 
 		zram_slot_unlock(zram, index);
 		mem = kmap_atomic(page);
-		zram_fill_page(mem + offset, len, zram->table[index].element);
+		zram_fill_page(mem + offset, len,
+					zram_get_element(zram, index));
 		kunmap_atomic(mem);
 		return true;
 	}
@@ -472,7 +483,7 @@ static void zram_meta_free(struct zram *zram, u64 disksize)
 
 	/* Free all pages that are still in this zram device */
 	for (index = 0; index < num_pages; index++) {
-		unsigned long handle = zram->table[index].handle;
+		unsigned long handle = zram_get_handle(zram, index);
 		/*
 		 * No memory is allocated for same element filled pages.
 		 * Simply clear same page flag.
@@ -512,7 +523,7 @@ static bool zram_meta_alloc(struct zram *zram, u64 disksize)
  */
 static void zram_free_page(struct zram *zram, size_t index)
 {
-	unsigned long handle = zram->table[index].handle;
+	unsigned long handle = zram_get_handle(zram, index);
 
 	/*
 	 * No memory is allocated for same element filled pages.
@@ -520,7 +531,7 @@ static void zram_free_page(struct zram *zram, size_t index)
 	 */
 	if (zram_test_flag(zram, index, ZRAM_SAME)) {
 		zram_clear_flag(zram, index, ZRAM_SAME);
-		zram_clear_element(zram, index);
+		zram_set_element(zram, index, 0);
 		atomic64_dec(&zram->stats.same_pages);
 		return;
 	}
@@ -534,7 +545,7 @@ static void zram_free_page(struct zram *zram, size_t index)
 			&zram->stats.compr_data_size);
 	atomic64_dec(&zram->stats.pages_stored);
 
-	zram->table[index].handle = 0;
+	zram_set_handle(zram, index, 0);
 	zram_set_obj_size(zram, index, 0);
 }
 
@@ -549,7 +560,7 @@ static int zram_decompress_page(struct zram *zram, struct page *page, u32 index)
 		return 0;
 
 	zram_slot_lock(zram, index);
-	handle = zram->table[index].handle;
+	handle = zram_get_handle(zram, index);
 	size = zram_get_obj_size(zram, index);
 
 	src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO);
@@ -715,7 +726,7 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)
 	 */
 	zram_slot_lock(zram, index);
 	zram_free_page(zram, index);
-	zram->table[index].handle = handle;
+	zram_set_handle(zram, index, handle);
 	zram_set_obj_size(zram, index, comp_len);
 	zram_slot_unlock(zram, index);
 
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 9+ messages in thread
* [PATCH v2 6/6] zram: use zram_free_page instead of open-coded
  2017-04-13  2:59 [PATCH v2 0/6] zram clean up Minchan Kim
                   ` (4 preceding siblings ...)
  2017-04-13  2:59 ` [PATCH v2 5/6] zram: introduce zram data accessor Minchan Kim
@ 2017-04-13  2:59 ` Minchan Kim
  5 siblings, 0 replies; 9+ messages in thread
From: Minchan Kim @ 2017-04-13  2:59 UTC (permalink / raw)
  To: Andrew Morton; +Cc: kernel-team, linux-kernel, Minchan Kim

The zram_free_page already handles NULL handle case and same page
so use it to reduce error probability.
(Acutaully, I made a mistake when I handled same page feature)

Signed-off-by: Minchan Kim <minchan@kernel.org>
---
 drivers/block/zram/zram_drv.c | 17 +++--------------
 1 file changed, 3 insertions(+), 14 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 22b249444010..210e449af4c6 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -482,17 +482,8 @@ static void zram_meta_free(struct zram *zram, u64 disksize)
 	size_t index;
 
 	/* Free all pages that are still in this zram device */
-	for (index = 0; index < num_pages; index++) {
-		unsigned long handle = zram_get_handle(zram, index);
-		/*
-		 * No memory is allocated for same element filled pages.
-		 * Simply clear same page flag.
-		 */
-		if (!handle || zram_test_flag(zram, index, ZRAM_SAME))
-			continue;
-
-		zs_free(zram->mem_pool, handle);
-	}
+	for (index = 0; index < num_pages; index++)
+		zram_free_page(zram, index);
 
 	zs_destroy_pool(zram->mem_pool);
 	vfree(zram->table);
@@ -976,9 +967,6 @@ static void zram_reset_device(struct zram *zram)
 
 	comp = zram->comp;
 	disksize = zram->disksize;
-
-	/* Reset stats */
-	memset(&zram->stats, 0, sizeof(zram->stats));
 	zram->disksize = 0;
 
 	set_capacity(zram->disk, 0);
@@ -987,6 +975,7 @@ static void zram_reset_device(struct zram *zram)
 	up_write(&zram->init_lock);
 	/* I/O operation under all of CPU are done so let's free */
 	zram_meta_free(zram, disksize);
+	memset(&zram->stats, 0, sizeof(zram->stats));
 	zcomp_destroy(comp);
 }
 
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 9+ messages in thread
* Re: [PATCH v2 1/6] zram: handle multiple pages attached bio's bvec
  2017-04-13  2:59 ` [PATCH v2 1/6] zram: handle multiple pages attached bio's bvec Minchan Kim
@ 2017-04-13  7:15   ` Johannes Thumshirn
  2017-04-13 13:40     ` Minchan Kim
  0 siblings, 1 reply; 9+ messages in thread
From: Johannes Thumshirn @ 2017-04-13  7:15 UTC (permalink / raw)
  To: Minchan Kim
  Cc: Andrew Morton, kernel-team, linux-kernel, Hannes Reinecke,
	Sergey Senozhatsky

On Thu, Apr 13, 2017 at 11:59:20AM +0900, Minchan Kim wrote:
> Johannes Thumshirn reported system goes the panic when using NVMe over
> Fabrics loopback target with zram.
> 
> The reason is zram expects each bvec in bio contains a single page
> but nvme can attach a huge bulk of pages attached to the bio's bvec
> so that zram's index arithmetic could be wrong so that out-of-bound
> access makes system panic.
> 
> [1] in mainline solved solved the problem by limiting max_sectors with
> SECTORS_PER_PAGE but it makes zram slow because bio should split with
> each pages so this patch makes zram aware of multiple pages in a bvec
> so it could solve without any regression(ie, bio split).
> 
> [1] 0bc315381fe9, zram: set physical queue limits to avoid array out of
>     bounds accesses
> 
> * from v1
>   * Do not exceed page boundary when set up bv.bv_len in make_request
>   * change "remained" variable name with "unwritten"
> 
> Cc: Hannes Reinecke <hare@suse.com>
> Reported-by: Johannes Thumshirn <jthumshirn@suse.de>
> Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> Signed-off-by: Minchan Kim <minchan@kernel.org>
> ---

Hi Minchan,

A quick amendment to your patch you forgot to remove the queue limit
setting which I introduced with commit 0bc315381fe9.

Thanks,
	Johannes

-- 
Johannes Thumshirn                                          Storage
jthumshirn@suse.de                                +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850

^ permalink raw reply	[flat|nested] 9+ messages in thread
* Re: [PATCH v2 1/6] zram: handle multiple pages attached bio's bvec
  2017-04-13  7:15   ` Johannes Thumshirn
@ 2017-04-13 13:40     ` Minchan Kim
  0 siblings, 0 replies; 9+ messages in thread
From: Minchan Kim @ 2017-04-13 13:40 UTC (permalink / raw)
  To: Johannes Thumshirn
  Cc: Andrew Morton, kernel-team, linux-kernel, Hannes Reinecke,
	Sergey Senozhatsky

Hi Johannes,

On Thu, Apr 13, 2017 at 09:15:00AM +0200, Johannes Thumshirn wrote:
> On Thu, Apr 13, 2017 at 11:59:20AM +0900, Minchan Kim wrote:
> > Johannes Thumshirn reported system goes the panic when using NVMe over
> > Fabrics loopback target with zram.
> > 
> > The reason is zram expects each bvec in bio contains a single page
> > but nvme can attach a huge bulk of pages attached to the bio's bvec
> > so that zram's index arithmetic could be wrong so that out-of-bound
> > access makes system panic.
> > 
> > [1] in mainline solved solved the problem by limiting max_sectors with
> > SECTORS_PER_PAGE but it makes zram slow because bio should split with
> > each pages so this patch makes zram aware of multiple pages in a bvec
> > so it could solve without any regression(ie, bio split).
> > 
> > [1] 0bc315381fe9, zram: set physical queue limits to avoid array out of
> >     bounds accesses
> > 
> > * from v1
> >   * Do not exceed page boundary when set up bv.bv_len in make_request
> >   * change "remained" variable name with "unwritten"
> > 
> > Cc: Hannes Reinecke <hare@suse.com>
> > Reported-by: Johannes Thumshirn <jthumshirn@suse.de>
> > Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
> > Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
> > Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> > Signed-off-by: Minchan Kim <minchan@kernel.org>
> > ---
> 
> Hi Minchan,
> 
> A quick amendment to your patch you forgot to remove the queue limit
> setting which I introduced with commit 0bc315381fe9.

It was my mistake. I made patches with reverting 0bc315381fe9.
Thanks for the review!

I think it is convenient to resend just this one for Andrew.
Andrew, Please take this as [1/6]. Sorry for the confusion.

>From c2f0e777f40a29c4fb56794b42df09f2188be9d6 Mon Sep 17 00:00:00 2001
From: Minchan Kim <minchan@kernel.org>
Date: Mon, 3 Apr 2017 08:46:45 +0900
Subject: [PATCH] zram: handle multiple pages attached bio's bvec

Johannes Thumshirn reported system goes the panic when using NVMe over
Fabrics loopback target with zram.

The reason is zram expects each bvec in bio contains a single page
but nvme can attach a huge bulk of pages attached to the bio's bvec
so that zram's index arithmetic could be wrong so that out-of-bound
access makes system panic.

[1] in mainline solved solved the problem by limiting max_sectors with
SECTORS_PER_PAGE but it makes zram slow because bio should split with
each pages so this patch makes zram aware of multiple pages in a bvec
so it could solve without any regression(ie, bio split).

[1] 0bc315381fe9, zram: set physical queue limits to avoid array out of
    bounds accesses

* from v1
  * Do not exceed page boundary when set up bv.bv_len in make_request
  * change "remained" variable name with "unwritten"

Cc: Hannes Reinecke <hare@suse.com>
Reported-by: Johannes Thumshirn <jthumshirn@suse.de>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
 drivers/block/zram/zram_drv.c | 40 +++++++++++-----------------------------
 1 file changed, 11 insertions(+), 29 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 11cc8767af99..ea0d20fabd89 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -137,8 +137,7 @@ static inline bool valid_io_request(struct zram *zram,
 
 static void update_position(u32 *index, int *offset, struct bio_vec *bvec)
 {
-	if (*offset + bvec->bv_len >= PAGE_SIZE)
-		(*index)++;
+	*index  += (*offset + bvec->bv_len) / PAGE_SIZE;
 	*offset = (*offset + bvec->bv_len) % PAGE_SIZE;
 }
 
@@ -838,34 +837,21 @@ static void __zram_make_request(struct zram *zram, struct bio *bio)
 	}
 
 	bio_for_each_segment(bvec, bio, iter) {
-		int max_transfer_size = PAGE_SIZE - offset;
-
-		if (bvec.bv_len > max_transfer_size) {
-			/*
-			 * zram_bvec_rw() can only make operation on a single
-			 * zram page. Split the bio vector.
-			 */
-			struct bio_vec bv;
-
-			bv.bv_page = bvec.bv_page;
-			bv.bv_len = max_transfer_size;
-			bv.bv_offset = bvec.bv_offset;
+		struct bio_vec bv = bvec;
+		unsigned int unwritten = bvec.bv_len;
 
+		do {
+			bv.bv_len = min_t(unsigned int, PAGE_SIZE - offset,
+							unwritten);
 			if (zram_bvec_rw(zram, &bv, index, offset,
-					 op_is_write(bio_op(bio))) < 0)
+					op_is_write(bio_op(bio))) < 0)
 				goto out;
 
-			bv.bv_len = bvec.bv_len - max_transfer_size;
-			bv.bv_offset += max_transfer_size;
-			if (zram_bvec_rw(zram, &bv, index + 1, 0,
-					 op_is_write(bio_op(bio))) < 0)
-				goto out;
-		} else
-			if (zram_bvec_rw(zram, &bvec, index, offset,
-					 op_is_write(bio_op(bio))) < 0)
-				goto out;
+			bv.bv_offset += bv.bv_len;
+			unwritten -= bv.bv_len;
 
-		update_position(&index, &offset, &bvec);
+			update_position(&index, &offset, &bv);
+		} while (unwritten);
 	}
 
 	bio_endio(bio);
@@ -882,8 +868,6 @@ static blk_qc_t zram_make_request(struct request_queue *queue, struct bio *bio)
 {
 	struct zram *zram = queue->queuedata;
 
-	blk_queue_split(queue, &bio, queue->bio_split);
-
 	if (!valid_io_request(zram, bio->bi_iter.bi_sector,
 					bio->bi_iter.bi_size)) {
 		atomic64_inc(&zram->stats.invalid_io);
@@ -1191,8 +1175,6 @@ static int zram_add(void)
 	blk_queue_io_min(zram->disk->queue, PAGE_SIZE);
 	blk_queue_io_opt(zram->disk->queue, PAGE_SIZE);
 	zram->disk->queue->limits.discard_granularity = PAGE_SIZE;
-	zram->disk->queue->limits.max_sectors = SECTORS_PER_PAGE;
-	zram->disk->queue->limits.chunk_sectors = 0;
 	blk_queue_max_discard_sectors(zram->disk->queue, UINT_MAX);
 	/*
 	 * zram_bio_discard() will clear all logical blocks if logical block
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 9+ messages in thread
end of thread, other threads:[~2017-04-13 13:41 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-04-13  2:59 [PATCH v2 0/6] zram clean up Minchan Kim
2017-04-13  2:59 ` [PATCH v2 1/6] zram: handle multiple pages attached bio's bvec Minchan Kim
2017-04-13  7:15   ` Johannes Thumshirn
2017-04-13 13:40     ` Minchan Kim
2017-04-13  2:59 ` [PATCH v2 2/6] zram: partial IO refactoring Minchan Kim
2017-04-13  2:59 ` [PATCH v2 3/6] zram: use zram_slot_lock instead of raw bit_spin_lock op Minchan Kim
2017-04-13  2:59 ` [PATCH v2 4/6] zram: remove zram_meta structure Minchan Kim
2017-04-13  2:59 ` [PATCH v2 5/6] zram: introduce zram data accessor Minchan Kim
2017-04-13  2:59 ` [PATCH v2 6/6] zram: use zram_free_page instead of open-coded Minchan Kim

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