+ dcssblk-handle-alloc_dax-eopnotsupp-failure.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: dcssblk: handle alloc_dax() -EOPNOTSUPP failure
has been added to the -mm mm-unstable branch.  Its filename is
     dcssblk-handle-alloc_dax-eopnotsupp-failure.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/dcssblk-handle-alloc_dax-eopnotsupp-failure.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: dcssblk: handle alloc_dax() -EOPNOTSUPP failure
Date: Mon, 12 Feb 2024 11:30:57 -0500

In preparation for checking whether the architecture has data cache
aliasing within alloc_dax(), modify the error handling of dcssblk
dcssblk_add_store() to handle alloc_dax() -EOPNOTSUPP failures.

Considering that s390 is not a data cache aliasing architecture, and
considering that DCSSBLK selects DAX, a return value of -EOPNOTSUPP from
alloc_dax() should make dcssblk_add_store() fail.

Link: https://lkml.kernel.org/r/20240212163101.19614-5-mathieu.desnoyers@efficios.com
Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing caches")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Michael Sclafani <dm-devel@lists.linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/s390/block/dcssblk.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

--- a/drivers/s390/block/dcssblk.c~dcssblk-handle-alloc_dax-eopnotsupp-failure
+++ a/drivers/s390/block/dcssblk.c
@@ -549,6 +549,7 @@ dcssblk_add_store(struct device *dev, st
 	int rc, i, j, num_of_segments;
 	struct dcssblk_dev_info *dev_info;
 	struct segment_info *seg_info, *temp;
+	struct dax_device *dax_dev;
 	char *local_buf;
 	unsigned long seg_byte_size;
 
@@ -677,13 +678,13 @@ dcssblk_add_store(struct device *dev, st
 	if (rc)
 		goto put_dev;
 
-	dev_info->dax_dev = alloc_dax(dev_info, &dcssblk_dax_ops);
-	if (IS_ERR(dev_info->dax_dev)) {
-		rc = PTR_ERR(dev_info->dax_dev);
-		dev_info->dax_dev = NULL;
+	dax_dev = alloc_dax(dev_info, &dcssblk_dax_ops);
+	if (IS_ERR(dax_dev)) {
+		rc = PTR_ERR(dax_dev);
 		goto put_dev;
 	}
-	set_dax_synchronous(dev_info->dax_dev);
+	set_dax_synchronous(dax_dev);
+	dev_info->dax_dev = dax_dev;
 	rc = dax_add_host(dev_info->dax_dev, dev_info->gd);
 	if (rc)
 		goto out_dax;
_

Patches currently in -mm which might be from mathieu.desnoyers@efficios.com are

nvdimm-pmem-fix-leak-on-dax_add_host-failure.patch
dax-alloc_dax-return-err_ptr-eopnotsupp-for-config_dax=n.patch
nvdimm-pmem-treat-alloc_dax-eopnotsupp-failure-as-non-fatal.patch
dm-treat-alloc_dax-eopnotsupp-failure-as-non-fatal.patch
dcssblk-handle-alloc_dax-eopnotsupp-failure.patch
virtio-treat-alloc_dax-eopnotsupp-failure-as-non-fatal.patch
dax-check-for-data-cache-aliasing-at-runtime.patch
introduce-cpu_dcache_is_aliasing-across-all-architectures.patch
dax-fix-incorrect-list-of-data-cache-aliasing-architectures.patch