diff mbox series

[PATCHv4,3/9] zram: Factor out WB and non-WB zram read functions

Message ID 20221018045533.2396670-4-senozhatsky@chromium.org
State New
Headers
Series zram: Support multiple compression streams |

Commit Message

Sergey Senozhatsky Oct. 18, 2022, 4:55 a.m. UTC 
  We will use non-WB variant in ZRAM page recompression path.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
---
 drivers/block/zram/zram_drv.c | 73 ++++++++++++++++++++++++-----------
 1 file changed, 50 insertions(+), 23 deletions(-)

Comments

Minchan Kim Nov. 2, 2022, 8:20 p.m. UTC | #1 
On Tue, Oct 18, 2022 at 01:55:27PM +0900, Sergey Senozhatsky wrote:
> We will use non-WB variant in ZRAM page recompression path.
> 
> Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> ---
>  drivers/block/zram/zram_drv.c | 73 ++++++++++++++++++++++++-----------
>  1 file changed, 50 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index a8ef3c0c3dae..94c62d7ea818 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -1314,8 +1314,30 @@ static void zram_free_page(struct zram *zram, size_t index)
>  		~(1UL << ZRAM_LOCK | 1UL << ZRAM_UNDER_WB));
>  }
>  
> -static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index,
> -				struct bio *bio, bool partial_io)
> +/*
> + * Reads a page from the writeback devices. Corresponding ZRAM slot
> + * should be unlocked.
> + */
> +static int zram_read_from_writeback(struct zram *zram, struct page *page,

How about zram_read_from_bdev?
Sergey Senozhatsky Nov. 3, 2022, 2:43 a.m. UTC | #2 
On (22/11/02 13:20), Minchan Kim wrote:
> On Tue, Oct 18, 2022 at 01:55:27PM +0900, Sergey Senozhatsky wrote:
> > We will use non-WB variant in ZRAM page recompression path.
> > 
> > Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> > ---
> >  drivers/block/zram/zram_drv.c | 73 ++++++++++++++++++++++++-----------
> >  1 file changed, 50 insertions(+), 23 deletions(-)
> > 
> > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> > index a8ef3c0c3dae..94c62d7ea818 100644
> > --- a/drivers/block/zram/zram_drv.c
> > +++ b/drivers/block/zram/zram_drv.c
> > @@ -1314,8 +1314,30 @@ static void zram_free_page(struct zram *zram, size_t index)
> >  		~(1UL << ZRAM_LOCK | 1UL << ZRAM_UNDER_WB));
> >  }
> >  
> > -static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index,
> > -				struct bio *bio, bool partial_io)
> > +/*
> > + * Reads a page from the writeback devices. Corresponding ZRAM slot
> > + * should be unlocked.
> > + */
> > +static int zram_read_from_writeback(struct zram *zram, struct page *page,
> 
> How about zram_read_from_bdev?

As far as I can see, we already have that one, so that name is already taken.

We have read_from_bdev, read_from_bdev_sync, read_from_bdev_async, and
probably some more.
diff mbox series

Patch

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index a8ef3c0c3dae..94c62d7ea818 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1314,8 +1314,30 @@  static void zram_free_page(struct zram *zram, size_t index)
 		~(1UL << ZRAM_LOCK | 1UL << ZRAM_UNDER_WB));
 }
 
-static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index,
-				struct bio *bio, bool partial_io)
+/*
+ * Reads a page from the writeback devices. Corresponding ZRAM slot
+ * should be unlocked.
+ */
+static int zram_read_from_writeback(struct zram *zram, struct page *page,
+				    u32 index, struct bio *bio,
+				    bool partial_io)
+{
+	struct bio_vec bvec;
+
+	bvec.bv_page = page;
+	bvec.bv_len = PAGE_SIZE;
+	bvec.bv_offset = 0;
+	return read_from_bdev(zram, &bvec,
+			      zram_get_element(zram, index),
+			      bio, partial_io);
+}
+
+/*
+ * Reads (decompresses if needed) a page from zspool (zsmalloc).
+ * Corresponding ZRAM slot should be locked.
+ */
+static int zram_read_from_zspool(struct zram *zram, struct page *page,
+				 u32 index)
 {
 	struct zcomp_strm *zstrm;
 	unsigned long handle;
@@ -1323,23 +1345,6 @@  static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index,
 	void *src, *dst;
 	int ret;
 
-	zram_slot_lock(zram, index);
-	if (zram_test_flag(zram, index, ZRAM_WB)) {
-		struct bio_vec bvec;
-
-		zram_slot_unlock(zram, index);
-		/* A null bio means rw_page was used, we must fallback to bio */
-		if (!bio)
-			return -EOPNOTSUPP;
-
-		bvec.bv_page = page;
-		bvec.bv_len = PAGE_SIZE;
-		bvec.bv_offset = 0;
-		return read_from_bdev(zram, &bvec,
-				zram_get_element(zram, index),
-				bio, partial_io);
-	}
-
 	handle = zram_get_handle(zram, index);
 	if (!handle || zram_test_flag(zram, index, ZRAM_SAME)) {
 		unsigned long value;
@@ -1349,7 +1354,6 @@  static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index,
 		mem = kmap_atomic(page);
 		zram_fill_page(mem, PAGE_SIZE, value);
 		kunmap_atomic(mem);
-		zram_slot_unlock(zram, index);
 		return 0;
 	}
 
@@ -1371,17 +1375,40 @@  static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index,
 		zcomp_stream_put(zram->comps[ZRAM_PRIMARY_ZCOMP]);
 	}
 	zs_unmap_object(zram->mem_pool, handle);
-	zram_slot_unlock(zram, index);
+	return ret;
+}
+
+static int __zram_bvec_read(struct zram *zram, struct page *page, u32 index,
+			    struct bio *bio, bool partial_io)
+{
+	int ret;
+
+	zram_slot_lock(zram, index);
+	if (!zram_test_flag(zram, index, ZRAM_WB)) {
+		/* Slot should be locked through out the function call */
+		ret = zram_read_from_zspool(zram, page, index);
+		zram_slot_unlock(zram, index);
+	} else {
+		/* Slot should be unlocked before the function call */
+		zram_slot_unlock(zram, index);
+
+		/* A null bio means rw_page was used, we must fallback to bio */
+		if (!bio)
+			return -EOPNOTSUPP;
+
+		ret = zram_read_from_writeback(zram, page, index, bio,
+					       partial_io);
+	}
 
 	/* Should NEVER happen. Return bio error if it does. */
-	if (WARN_ON(ret))
+	if (WARN_ON(ret < 0))
 		pr_err("Decompression failed! err=%d, page=%u\n", ret, index);
 
 	return ret;
 }
 
 static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
-				u32 index, int offset, struct bio *bio)
+			  u32 index, int offset, struct bio *bio)
 {
 	int ret;
 	struct page *page;