In preparation for CONFIG_DAX growing a CONFIG_MMU dependency add support for pmem to skip dax-device registration in the CONFIG_DAX=n case.
alloc_dax() returns NULL in the CONFIG_DAX=n case, ERR_PTR() in the failure case, and a dax-device in the success case. dax_remove_host(), kill_dax() and put_dax() are safe to call if setup_dax() returns 0 because it suceeded, or 0 because CONFIG_DAX=n. Signed-off-by: Dan Williams <[email protected]> --- drivers/nvdimm/Kconfig | 2 +- drivers/nvdimm/pmem.c | 47 ++++++++++++++++++++++++++++++----------------- 2 files changed, 31 insertions(+), 18 deletions(-) diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig index 5a29046e3319..027acca1bac4 100644 --- a/drivers/nvdimm/Kconfig +++ b/drivers/nvdimm/Kconfig @@ -19,7 +19,7 @@ if LIBNVDIMM config BLK_DEV_PMEM tristate "PMEM: Persistent memory block device support" default LIBNVDIMM - select DAX + select DAX if MMU select ND_BTT if BTT select ND_PFN if NVDIMM_PFN help diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c index 7e88cd242380..068183ee9bf6 100644 --- a/drivers/nvdimm/pmem.c +++ b/drivers/nvdimm/pmem.c @@ -468,6 +468,32 @@ static const struct dev_pagemap_ops fsdax_pagemap_ops = { .memory_failure = pmem_pagemap_memory_failure, }; +static int setup_dax(struct pmem_device *pmem, struct gendisk *disk, + struct nd_region *nd_region) +{ + struct dax_device *dax_dev; + int rc; + + dax_dev = alloc_dax(pmem, &pmem_dax_ops); + if (IS_ERR(dax_dev)) + return PTR_ERR(dax_dev); + if (!dax_dev) + return 0; + set_dax_nocache(dax_dev); + set_dax_nomc(dax_dev); + if (is_nvdimm_sync(nd_region)) + set_dax_synchronous(dax_dev); + rc = dax_add_host(dax_dev, disk); + if (rc) { + kill_dax(dax_dev); + put_dax(dax_dev); + return rc; + } + dax_write_cache(dax_dev, nvdimm_has_cache(nd_region)); + pmem->dax_dev = dax_dev; + return 0; +} + static int pmem_attach_disk(struct device *dev, struct nd_namespace_common *ndns) { @@ -477,7 +503,6 @@ static int pmem_attach_disk(struct device *dev, struct resource *res = &nsio->res; struct range bb_range; struct nd_pfn *nd_pfn = NULL; - struct dax_device *dax_dev; struct nd_pfn_sb *pfn_sb; struct pmem_device *pmem; struct request_queue *q; @@ -578,24 +603,13 @@ static int pmem_attach_disk(struct device *dev, nvdimm_badblocks_populate(nd_region, &pmem->bb, &bb_range); disk->bb = &pmem->bb; - dax_dev = alloc_dax(pmem, &pmem_dax_ops); - if (IS_ERR(dax_dev)) { - rc = PTR_ERR(dax_dev); - goto out; - } - set_dax_nocache(dax_dev); - set_dax_nomc(dax_dev); - if (is_nvdimm_sync(nd_region)) - set_dax_synchronous(dax_dev); - rc = dax_add_host(dax_dev, disk); + rc = setup_dax(pmem, disk, nd_region); if (rc) - goto out_cleanup_dax; - dax_write_cache(dax_dev, nvdimm_has_cache(nd_region)); - pmem->dax_dev = dax_dev; + goto out; rc = device_add_disk(dev, disk, pmem_attribute_groups); if (rc) - goto out_remove_host; + goto out_dax; if (devm_add_action_or_reset(dev, pmem_release_disk, pmem)) return -ENOMEM; @@ -607,9 +621,8 @@ static int pmem_attach_disk(struct device *dev, dev_warn(dev, "'badblocks' notification disabled\n"); return 0; -out_remove_host: +out_dax: dax_remove_host(pmem->disk); -out_cleanup_dax: kill_dax(pmem->dax_dev); put_dax(pmem->dax_dev); out:
