zram: don't pass a bvec to __zram_bvec_write

__zram_bvec_write only extracts the page from __zram_bvec_write and always
expects a full page of input.  Pass the page directly instead of the bvec
and rename the function to zram_write_page.

Link: https://lkml.kernel.org/r/20230411171459.567614-13-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

drivers/block/zram/zram_drv.c

@@ -1443,16 +1443,14 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
 	return zram_read_page(zram, bvec->bv_page, index, bio, false);
 }
 
-static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec,
-				u32 index, struct bio *bio)
+static int zram_write_page(struct zram *zram, struct page *page, u32 index)
 {
 	int ret = 0;
 	unsigned long alloced_pages;
 	unsigned long handle = -ENOMEM;
 	unsigned int comp_len = 0;
 	void *src, *dst, *mem;
 	struct zcomp_strm *zstrm;
-	struct page *page = bvec->bv_page;
 	unsigned long element = 0;
 	enum zram_pageflags flags = 0;
 
@@ -1573,11 +1571,9 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec,
 static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec,
 				u32 index, int offset, struct bio *bio)
 {
+	struct page *page = bvec->bv_page;
 	int ret;
-	struct page *page = NULL;
-	struct bio_vec vec;
 
-	vec = *bvec;
 	if (is_partial_io(bvec)) {
 		/*
 		 * This is a partial IO. We need to read the full page
@@ -1592,11 +1588,9 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec,
 			goto out;
 
 		memcpy_from_bvec(page_address(page) + offset, bvec);
-
-		bvec_set_page(&vec, page, PAGE_SIZE, 0);
 	}
 
-	ret = __zram_bvec_write(zram, &vec, index, bio);
+	ret = zram_write_page(zram, page, index);
 out:
 	if (is_partial_io(bvec))
 		__free_page(page);
@@ -1711,7 +1705,7 @@ static int zram_recompress(struct zram *zram, u32 index, struct page *page,
 
 	/*
 	 * No direct reclaim (slow path) for handle allocation and no
-	 * re-compression attempt (unlike in __zram_bvec_write()) since
+	 * re-compression attempt (unlike in zram_write_bvec()) since
 	 * we already have stored that object in zsmalloc. If we cannot
 	 * alloc memory for recompressed object then we bail out and
 	 * simply keep the old (existing) object in zsmalloc.