linux-kernel - [PATCH 1/2] bcachefs: Simplify bch2_bio

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Message-Id: <20250605020639.6868-1-youling.tang@linux.dev>
Date: Thu,  5 Jun 2025 10:06:38 +0800
From: Youling Tang <youling.tang@...ux.dev>
To: Kent Overstreet <kent.overstreet@...ux.dev>
Cc: linux-bcachefs@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	youling.tang@...ux.dev,
	Youling Tang <tangyouling@...inos.cn>
Subject: [PATCH 1/2] bcachefs: Simplify bch2_bio_map()

From: Youling Tang <tangyouling@...inos.cn>

For the part of directly mapping the kernel virtual address, there is no
need to increase to bio page-by-page. It can be directly replaced by
bio_add_virt_nofail().

For the address part of the vmalloc region, its physical address is
discontinuous and needs to be increased page-by-page to bio. The helper
function bio_add_vmalloc() can be used to simplify the implementation of
bch2_bio_map().

Signed-off-by: Youling Tang <tangyouling@...inos.cn>
---
NOTE:
The following patch needs to be applied (because the bcachefs.git repository
has not been synchronized to the latest):
commit 850e210d5ad2 ("block: add a bio_add_virt_nofail helper")
commit 8dd16f5e3469 ("block: add a bio_add_vmalloc helpers")

 fs/bcachefs/util.c | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/fs/bcachefs/util.c b/fs/bcachefs/util.c
index dc3817f545fa..5e5075630bc6 100644
--- a/fs/bcachefs/util.c
+++ b/fs/bcachefs/util.c
@@ -623,17 +623,10 @@ void bch2_pd_controller_debug_to_text(struct printbuf *out, struct bch_pd_contro
 
 void bch2_bio_map(struct bio *bio, void *base, size_t size)
 {
-	while (size) {
-		struct page *page = is_vmalloc_addr(base)
-				? vmalloc_to_page(base)
-				: virt_to_page(base);
-		unsigned offset = offset_in_page(base);
-		unsigned len = min_t(size_t, PAGE_SIZE - offset, size);
-
-		BUG_ON(!bio_add_page(bio, page, len, offset));
-		size -= len;
-		base += len;
-	}
+	if (is_vmalloc_addr(base))
+		bio_add_vmalloc(bio, base, size);
+	else
+		bio_add_virt_nofail(bio, base, size);
 }
 
 int bch2_bio_alloc_pages(struct bio *bio, size_t size, gfp_t gfp_mask)
-- 
2.34.1