linux-kernel - [RFC PATCH 6/8] zram: factor out ZRAM

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Message-ID: <20241118103054.3191944-7-senozhatsky@chromium.org>
Date: Mon, 18 Nov 2024 19:30:37 +0900
From: Sergey Senozhatsky <senozhatsky@...omium.org>
To: Andrew Morton <akpm@...ux-foundation.org>,
	Minchan Kim <minchan@...nel.org>
Cc: linux-kernel@...r.kernel.org,
	Sergey Senozhatsky <senozhatsky@...omium.org>
Subject: [RFC PATCH 6/8] zram: factor out ZRAM_HUGE read

Similarly to write, move ZRAM_HUGE read handlig to a separate
function.  This will make more sense with introduction of
multi-handle entries later in the series.

Signed-off-by: Sergey Senozhatsky <senozhatsky@...omium.org>
---
 drivers/block/zram/zram_drv.c | 71 ++++++++++++++++++++++-------------
 1 file changed, 44 insertions(+), 27 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 55ffd0534470..745207597e23 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1525,6 +1525,46 @@ static void zram_free_page(struct zram *zram, size_t index)
 	zram_set_obj_size(zram, index, 0);
 }
 
+static int read_incompressible_page(struct zram *zram, struct page *page,
+				    u32 index)
+{
+	unsigned long handle;
+	void *src, *dst;
+
+	handle = zram_get_handle(zram, index);
+	src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO);
+	dst = kmap_local_page(page);
+	copy_page(dst, src);
+	kunmap_local(dst);
+	zs_unmap_object(zram->mem_pool, handle);
+
+	return 0;
+}
+
+static int read_compressible_page(struct zram *zram, struct page *page,
+				  u32 index)
+{
+	struct zcomp_strm *zstrm;
+	unsigned long handle;
+	unsigned int size;
+	void *src, *dst;
+	int ret, prio;
+
+	handle = zram_get_handle(zram, index);
+	size = zram_get_obj_size(zram, index);
+	prio = zram_get_priority(zram, index);
+
+	zstrm = zcomp_stream_get(zram->comps[prio]);
+	src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO);
+	dst = kmap_local_page(page);
+	ret = zcomp_decompress(zram->comps[prio], zstrm, src, size, dst);
+	kunmap_local(dst);
+	zs_unmap_object(zram->mem_pool, handle);
+	zcomp_stream_put(zram->comps[prio]);
+
+	return ret;
+}
+
 /*
  * Reads (decompresses if needed) a page from zspool (zsmalloc).
  * Corresponding ZRAM slot should be locked.
@@ -1532,12 +1572,7 @@ static void zram_free_page(struct zram *zram, size_t index)
 static int zram_read_from_zspool(struct zram *zram, struct page *page,
 				 u32 index)
 {
-	struct zcomp_strm *zstrm;
 	unsigned long handle;
-	unsigned int size;
-	void *src, *dst;
-	u32 prio;
-	int ret;
 
 	handle = zram_get_handle(zram, index);
 	if (!handle || zram_test_flag(zram, index, ZRAM_SAME)) {
@@ -1549,28 +1584,10 @@ static int zram_read_from_zspool(struct zram *zram, struct page *page,
 		return 0;
 	}
 
-	size = zram_get_obj_size(zram, index);
-
-	if (size != PAGE_SIZE) {
-		prio = zram_get_priority(zram, index);
-		zstrm = zcomp_stream_get(zram->comps[prio]);
-	}
-
-	src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO);
-	if (size == PAGE_SIZE) {
-		dst = kmap_local_page(page);
-		copy_page(dst, src);
-		kunmap_local(dst);
-		ret = 0;
-	} else {
-		dst = kmap_local_page(page);
-		ret = zcomp_decompress(zram->comps[prio], zstrm,
-				       src, size, dst);
-		kunmap_local(dst);
-		zcomp_stream_put(zram->comps[prio]);
-	}
-	zs_unmap_object(zram->mem_pool, handle);
-	return ret;
+	if (!zram_test_flag(zram, index, ZRAM_HUGE))
+		return read_compressible_page(zram, page, index);
+	else
+		return read_incompressible_page(zram, page, index);
 }
 
 static int zram_read_page(struct zram *zram, struct page *page, u32 index,
-- 
2.47.0.338.g60cca15819-goog