diff mbox series

[5.8,165/186] dm writecache: handle DAX to partitions on persistent memory correctly

Message ID 20200908152249.661695677@linuxfoundation.org
State Superseded
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman Sept. 8, 2020, 3:25 p.m. UTC 
From: Mikulas Patocka <mpatocka@redhat.com>

commit f9e040efcc28309e5c592f7e79085a9a52e31f58 upstream.

The function dax_direct_access doesn't take partitions into account,
it always maps pages from the beginning of the device. Therefore,
persistent_memory_claim() must get the partition offset using
get_start_sect() and add it to the page offsets passed to
dax_direct_access().

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: 48debafe4f2f ("dm: add writecache target")
Cc: stable@vger.kernel.org # 4.18+
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/md/dm-writecache.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)
diff mbox series

Patch

--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -231,6 +231,7 @@  static int persistent_memory_claim(struc
 	pfn_t pfn;
 	int id;
 	struct page **pages;
+	sector_t offset;
 
 	wc->memory_vmapped = false;
 
@@ -245,9 +246,16 @@  static int persistent_memory_claim(struc
 		goto err1;
 	}
 
+	offset = get_start_sect(wc->ssd_dev->bdev);
+	if (offset & (PAGE_SIZE / 512 - 1)) {
+		r = -EINVAL;
+		goto err1;
+	}
+	offset >>= PAGE_SHIFT - 9;
+
 	id = dax_read_lock();
 
-	da = dax_direct_access(wc->ssd_dev->dax_dev, 0, p, &wc->memory_map, &pfn);
+	da = dax_direct_access(wc->ssd_dev->dax_dev, offset, p, &wc->memory_map, &pfn);
 	if (da < 0) {
 		wc->memory_map = NULL;
 		r = da;
@@ -269,7 +277,7 @@  static int persistent_memory_claim(struc
 		i = 0;
 		do {
 			long daa;
-			daa = dax_direct_access(wc->ssd_dev->dax_dev, i, p - i,
+			daa = dax_direct_access(wc->ssd_dev->dax_dev, offset + i, p - i,
 						NULL, &pfn);
 			if (daa <= 0) {
 				r = daa ? daa : -EINVAL;