From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 835B71B21BF for ; Mon, 21 Apr 2025 07:27:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745220439; cv=none; b=ISWRlOO0z0j42Ns2kb3e/65FdWHmv+ViBTS8f9VRKKNVrH004mbITI+9IyhuQzzJ1YTP4WTTEJmE9Ix68O8HqL0tjIkhiSkhhci0E7EDha2ZAnvWWhof3D/TttwtnazOtokj64irWns1JLUkTP+rRqWfQ/+RukvEbIAl+aYGUZo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745220439; c=relaxed/simple; bh=/uiS1far/JlBYz4avglnZjgL6T1pW+4M29l6EWZzEug=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=aq4eYxIkBRXcrmoEnXd3o30y1OBKqgEkYGlyQ8rLDnW8YrPo6DCp0DFcluXEk4uYBEXHVgYv5OoqjV+plxqF5LLPNbVyujIj1VjnRZ2/+8xB37MNQ1NxlfjcjyG36BAzkCtom9GtAq4QwzbJlTEwIaN8uhGBWNAmEYFpFNKmgZI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=lst.de; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=XK7kKSas; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="XK7kKSas" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=b8S6O16FZwOzow767bmfyPDaHZKiuKSpdg+87NbQ+Ak=; b=XK7kKSasIisO1oVozhvLJT3ars VChc3TG18BGTzInRZ4HNjdB7b3aGM+i5ONYB1gzsdC/zHSGCjolfvHQV//5Ay1FZXK6IwyTTRYJKj bP9yBvCZQ0134VaAkz/FAjZVqtyNgdjhH3D3xLPEMQFz3Z90FfMxNCpUlvkEQcPSFZl8TUebl8ubV tB3VO1xEFQi9agfpsnPx9qc96aXnBP1j+F675uoPmziJJhEFa4fUuYs1mMmaTieG5b6FrOSoA0gHD TU7RBZs8LxBrK7rLA6ovS70Tkd2/F7Op3vGUBc/23tnNxKmbwdg2h+3vaO1LNFxUtJ/z+xAkQJe99 MOEMN25A==; Received: from [213.208.157.109] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1u6lYg-00000003n5E-2O3Y; Mon, 21 Apr 2025 07:27:15 +0000 From: Christoph Hellwig To: Jens Axboe , Yu Kuai Cc: linux-block@vger.kernel.org Subject: [PATCH 5/5] brd: use memcpy_{to,from]_page in brd_rw_bvec Date: Mon, 21 Apr 2025 09:26:09 +0200 Message-ID: <20250421072641.1311040-6-hch@lst.de> X-Mailer: git-send-email 2.47.2 In-Reply-To: <20250421072641.1311040-1-hch@lst.de> References: <20250421072641.1311040-1-hch@lst.de> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Use the proper helpers to copy to/from potential highmem pages, which do a local instead of atomic kmap underneath, and perform flush_dcache_page where needed. This also simplifies the code so much that the separate read write helpers are not required any more. Signed-off-by: Christoph Hellwig --- drivers/block/brd.c | 57 ++++++++++----------------------------------- 1 file changed, 12 insertions(+), 45 deletions(-) diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 580b2d8ce99c..79e96221f887 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -99,43 +99,6 @@ static void brd_free_pages(struct brd_device *brd) xa_destroy(&brd->brd_pages); } -/* - * Copy n bytes from src to the brd starting at sector. Does not sleep. - */ -static void copy_to_brd(struct brd_device *brd, const void *src, - sector_t sector, size_t n) -{ - struct page *page; - void *dst; - unsigned int offset = (sector & (PAGE_SECTORS-1)) << SECTOR_SHIFT; - - page = brd_lookup_page(brd, sector); - BUG_ON(!page); - - dst = kmap_atomic(page); - memcpy(dst + offset, src, n); - kunmap_atomic(dst); -} - -/* - * Copy n bytes to dst from the brd starting at sector. Does not sleep. - */ -static void copy_from_brd(void *dst, struct brd_device *brd, - sector_t sector, size_t n) -{ - struct page *page; - void *src; - unsigned int offset = (sector & (PAGE_SECTORS-1)) << SECTOR_SHIFT; - - page = brd_lookup_page(brd, sector); - if (page) { - src = kmap_atomic(page); - memcpy(dst, src + offset, n); - kunmap_atomic(src); - } else - memset(dst, 0, n); -} - /* * Process a single segment. The segment is capped to not cross page boundaries * in both the bio and the brd backing memory. @@ -146,7 +109,8 @@ static bool brd_rw_bvec(struct brd_device *brd, struct bio *bio) sector_t sector = bio->bi_iter.bi_sector; u32 offset = (sector & (PAGE_SECTORS - 1)) << SECTOR_SHIFT; blk_opf_t opf = bio->bi_opf; - void *mem; + struct page *page; + void *kaddr; bv.bv_len = min_t(u32, bv.bv_len, PAGE_SIZE - offset); @@ -168,15 +132,18 @@ static bool brd_rw_bvec(struct brd_device *brd, struct bio *bio) } } - mem = bvec_kmap_local(&bv); - if (!op_is_write(opf)) { - copy_from_brd(mem, brd, sector, bv.bv_len); - flush_dcache_page(bv.bv_page); + page = brd_lookup_page(brd, sector); + + kaddr = bvec_kmap_local(&bv); + if (op_is_write(opf)) { + BUG_ON(!page); + memcpy_to_page(page, offset, kaddr, bv.bv_len); + } else if (page) { + memcpy_from_page(kaddr, page, offset, bv.bv_len); } else { - flush_dcache_page(bv.bv_page); - copy_to_brd(brd, mem, sector, bv.bv_len); + memset(kaddr, 0, bv.bv_len); } - kunmap_local(mem); + kunmap_local(kaddr); bio_advance_iter_single(bio, &bio->bi_iter, bv.bv_len); return true; -- 2.47.2