zero_page_range() dax operation is mandatory for dax devices. Right now that check happens in dax_zero_page_range() function. Dan thinks that's too late and its better to do the check earlier in alloc_dax().
I also modified alloc_dax() to return pointer with error code in it in case of failure. Right now it returns NULL and caller assumes failure happened due to -ENOMEM. But with this ->zero_page_range() check, I need to return -EINVAL instead. Signed-off-by: Vivek Goyal <[email protected]> --- drivers/dax/bus.c | 4 +++- drivers/dax/super.c | 14 +++++++++----- drivers/md/dm.c | 2 +- drivers/nvdimm/pmem.c | 4 ++-- drivers/s390/block/dcssblk.c | 5 +++-- 5 files changed, 18 insertions(+), 11 deletions(-) Index: redhat-linux/drivers/dax/super.c =================================================================== --- redhat-linux.orig/drivers/dax/super.c 2020-04-01 12:03:39.911439769 -0400 +++ redhat-linux/drivers/dax/super.c 2020-04-01 12:05:31.727439769 -0400 @@ -349,9 +349,6 @@ int dax_zero_page_range(struct dax_devic { if (!dax_alive(dax_dev)) return -ENXIO; - - if (!dax_dev->ops->zero_page_range) - return -EOPNOTSUPP; /* * There are no callers that want to zero more than one page as of now. * Once users are there, this check can be removed after the @@ -571,9 +568,16 @@ struct dax_device *alloc_dax(void *priva dev_t devt; int minor; + if (ops && !ops->zero_page_range) { + pr_debug("%s: error: device does not provide dax" + " operation zero_page_range()\n", + __host ? __host : "Unknown"); + return ERR_PTR(-EINVAL); + } + host = kstrdup(__host, GFP_KERNEL); if (__host && !host) - return NULL; + return ERR_PTR(-ENOMEM); minor = ida_simple_get(&dax_minor_ida, 0, MINORMASK+1, GFP_KERNEL); if (minor < 0) @@ -596,7 +600,7 @@ struct dax_device *alloc_dax(void *priva ida_simple_remove(&dax_minor_ida, minor); err_minor: kfree(host); - return NULL; + return ERR_PTR(-ENOMEM); } EXPORT_SYMBOL_GPL(alloc_dax); Index: redhat-linux/drivers/nvdimm/pmem.c =================================================================== --- redhat-linux.orig/drivers/nvdimm/pmem.c 2020-04-01 12:03:39.911439769 -0400 +++ redhat-linux/drivers/nvdimm/pmem.c 2020-04-01 12:05:31.729439769 -0400 @@ -487,9 +487,9 @@ static int pmem_attach_disk(struct devic if (is_nvdimm_sync(nd_region)) flags = DAXDEV_F_SYNC; dax_dev = alloc_dax(pmem, disk->disk_name, &pmem_dax_ops, flags); - if (!dax_dev) { + if (IS_ERR(dax_dev)) { put_disk(disk); - return -ENOMEM; + return PTR_ERR(dax_dev); } dax_write_cache(dax_dev, nvdimm_has_cache(nd_region)); pmem->dax_dev = dax_dev; Index: redhat-linux/drivers/dax/bus.c =================================================================== --- redhat-linux.orig/drivers/dax/bus.c 2020-04-01 12:03:39.911439769 -0400 +++ redhat-linux/drivers/dax/bus.c 2020-04-01 12:05:31.729439769 -0400 @@ -421,8 +421,10 @@ struct dev_dax *__devm_create_dev_dax(st * device outside of mmap of the resulting character device. */ dax_dev = alloc_dax(dev_dax, NULL, NULL, DAXDEV_F_SYNC); - if (!dax_dev) + if (IS_ERR(dax_dev)) { + rc = PTR_ERR(dax_dev); goto err; + } /* a device_dax instance is dead while the driver is not attached */ kill_dax(dax_dev); Index: redhat-linux/drivers/s390/block/dcssblk.c =================================================================== --- redhat-linux.orig/drivers/s390/block/dcssblk.c 2020-04-01 12:03:39.911439769 -0400 +++ redhat-linux/drivers/s390/block/dcssblk.c 2020-04-01 12:05:31.730439769 -0400 @@ -695,8 +695,9 @@ dcssblk_add_store(struct device *dev, st dev_info->dax_dev = alloc_dax(dev_info, dev_info->gd->disk_name, &dcssblk_dax_ops, DAXDEV_F_SYNC); - if (!dev_info->dax_dev) { - rc = -ENOMEM; + if (IS_ERR(dev_info->dax_dev)) { + rc = PTR_ERR(dev_info->dax_dev); + dev_info->dax_dev = NULL; goto put_dev; } Index: redhat-linux/drivers/md/dm.c =================================================================== --- redhat-linux.orig/drivers/md/dm.c 2020-04-01 12:03:39.911439769 -0400 +++ redhat-linux/drivers/md/dm.c 2020-04-01 12:05:31.732439769 -0400 @@ -2005,7 +2005,7 @@ static struct mapped_device *alloc_dev(i if (IS_ENABLED(CONFIG_DAX_DRIVER)) { md->dax_dev = alloc_dax(md, md->disk->disk_name, &dm_dax_ops, 0); - if (!md->dax_dev) + if (IS_ERR(md->dax_dev)) goto bad; } -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
