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. For the transition, consider that alloc_dax() returning NULL is the same as returning -EOPNOTSUPP. Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing caches") Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> Cc: Alasdair Kergon <agk@xxxxxxxxxx> Cc: Mike Snitzer <snitzer@xxxxxxxxxx> Cc: Mikulas Patocka <mpatocka@xxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Vishal Verma <vishal.l.verma@xxxxxxxxx> Cc: Dave Jiang <dave.jiang@xxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Russell King <linux@xxxxxxxxxxxxxxx> Cc: linux-arch@xxxxxxxxxxxxxxx Cc: linux-cxl@xxxxxxxxxxxxxxx Cc: linux-fsdevel@xxxxxxxxxxxxxxx Cc: linux-mm@xxxxxxxxx Cc: linux-xfs@xxxxxxxxxxxxxxx Cc: dm-devel@xxxxxxxxxxxxxxx Cc: nvdimm@xxxxxxxxxxxxxxx Cc: linux-s390@xxxxxxxxxxxxxxx --- drivers/s390/block/dcssblk.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c index 4b7ecd4fd431..a3010849bfed 100644 --- a/drivers/s390/block/dcssblk.c +++ b/drivers/s390/block/dcssblk.c @@ -549,6 +549,7 @@ dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char 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, struct device_attribute *attr, const char 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_OR_NULL(dax_dev)) { + rc = IS_ERR(dax_dev) ? PTR_ERR(dax_dev) : -EOPNOTSUPP; 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; -- 2.39.2