Re: [PATCH 12/15] mm, dax: enable filesystems to trigger page-idle callbacks

+DEFINE_MUTEX(devmap_lock);

+#if IS_ENABLED(CONFIG_FS_DAX) +static void generic_dax_pagefree(struct page *page, void *data) +{ +} + +struct dax_device *fs_dax_claim_bdev(struct block_device *bdev, void *owner) +{ + struct dax_device *dax_dev; + struct dev_pagemap *pgmap; + + if (!blk_queue_dax(bdev->bd_queue)) + return NULL; + dax_dev = fs_dax_get_by_host(bdev->bd_disk->disk_name); + if (!dax_dev->pgmap) + return dax_dev; + pgmap = dax_dev->pgmap;

+ mutex_lock(&devmap_lock); + if ((pgmap->data && pgmap->data != owner) || pgmap->page_free + || pgmap->page_fault + || pgmap->type != MEMORY_DEVICE_HOST) { + put_dax(dax_dev); + mutex_unlock(&devmap_lock); + return NULL; + } + + pgmap->type = MEMORY_DEVICE_FS_DAX; + pgmap->page_free = generic_dax_pagefree; + pgmap->data = owner; + mutex_unlock(&devmap_lock);