Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Christoph Hellwig <hch@lst.de>
To:     Dan Williams <dan.j.williams@intel.com>
Cc:     Mike Snitzer <snitzer@redhat.com>, Ira Weiny <ira.weiny@intel.com>,
        dm-devel@redhat.com, linux-xfs@vger.kernel.org,
        nvdimm@lists.linux.dev, linux-s390@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-erofs@lists.ozlabs.org,
        linux-ext4@vger.kernel.org,
        virtualization@lists.linux-foundation.org
Subject: [PATCH 17/29] fsdax: factor out a dax_memzero helper
Date:   Tue,  9 Nov 2021 09:32:57 +0100
Message-Id: <20211109083309.584081-18-hch@lst.de>
In-Reply-To: <20211109083309.584081-1-hch@lst.de>
References: <20211109083309.584081-1-hch@lst.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Factor out a helper for the "manual" zeroing of a DAX range to clean
up dax_iomap_zero a lot.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/dax.c | 36 +++++++++++++++++++-----------------
 1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index d7a923d152240..dc9ebeff850ab 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1121,34 +1121,36 @@ static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf,
 }
 #endif /* CONFIG_FS_DAX_PMD */
 
+static int dax_memzero(struct dax_device *dax_dev, pgoff_t pgoff,
+		unsigned int offset, size_t size)
+{
+	void *kaddr;
+	long rc;
+
+	rc = dax_direct_access(dax_dev, pgoff, 1, &kaddr, NULL);
+	if (rc >= 0) {
+		memset(kaddr + offset, 0, size);
+		dax_flush(dax_dev, kaddr + offset, size);
+	}
+	return rc;
+}
+
 s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap)
 {
 	pgoff_t pgoff = dax_iomap_pgoff(iomap, pos);
 	long rc, id;
-	void *kaddr;
-	bool page_aligned = false;
 	unsigned offset = offset_in_page(pos);
 	unsigned size = min_t(u64, PAGE_SIZE - offset, length);
 
-	if (IS_ALIGNED(pos, PAGE_SIZE) && size == PAGE_SIZE)
-		page_aligned = true;
-
 	id = dax_read_lock();
-
-	if (page_aligned)
+	if (IS_ALIGNED(pos, PAGE_SIZE) && size == PAGE_SIZE)
 		rc = dax_zero_page_range(iomap->dax_dev, pgoff, 1);
 	else
-		rc = dax_direct_access(iomap->dax_dev, pgoff, 1, &kaddr, NULL);
-	if (rc < 0) {
-		dax_read_unlock(id);
-		return rc;
-	}
-
-	if (!page_aligned) {
-		memset(kaddr + offset, 0, size);
-		dax_flush(iomap->dax_dev, kaddr + offset, size);
-	}
+		rc = dax_memzero(iomap->dax_dev, pgoff, offset, size);
 	dax_read_unlock(id);
+
+	if (rc < 0)
+		return rc;
 	return size;
 }
 
-- 
2.30.2