[PATCH 04/13] fs/dax: Add dax_page_free callback
From: Alistair Popple <apopple@nvidia.com>
Date: 2024-06-27 00:54:58
Also in:
linux-arm-kernel, linux-cxl, linux-doc, linux-ext4, linux-fsdevel, linux-mm, linux-xfs, lkml, nvdimm
Subsystem:
filesystem direct access (dax), filesystems (vfs and infrastructure), fuse: filesystem in userspace, libnvdimm pmem: persistent memory driver, libnvdimm: non-volatile memory device subsystem, the rest, virtio file system · Maintainers:
Dan Williams, Alexander Viro, Christian Brauner, Miklos Szeredi, Vishal Verma, Dave Jiang, Ira Weiny, Linus Torvalds, German Maglione, Vivek Goyal, Stefan Hajnoczi
When a fs dax page is freed it has to notify filesystems that the page has been unpinned/unmapped and is free. Currently this involves special code in the page free paths to detect a transition of refcount from 2 to 1 and to call some fs dax specific code. A future change will require this to happen when the page refcount drops to zero. In this case we can use the existing pgmap->ops->page_free() callback so wire that up for all devices that support FS DAX (nvdimm and virtio). Signed-off-by: Alistair Popple <apopple@nvidia.com> --- drivers/nvdimm/pmem.c | 1 + fs/dax.c | 6 ++++++ fs/fuse/virtio_fs.c | 5 +++++ include/linux/dax.h | 1 + 4 files changed, 13 insertions(+)
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 598fe2e..cafadd0 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c@@ -444,6 +444,7 @@ static int pmem_pagemap_memory_failure(struct dev_pagemap *pgmap, static const struct dev_pagemap_ops fsdax_pagemap_ops = { .memory_failure = pmem_pagemap_memory_failure, + .page_free = dax_page_free, }; static int pmem_attach_disk(struct device *dev,
diff --git a/fs/dax.c b/fs/dax.c
index becb4a6..f93afd7 100644
--- a/fs/dax.c
+++ b/fs/dax.c@@ -2065,3 +2065,9 @@ int dax_remap_file_range_prep(struct file *file_in, loff_t pos_in, pos_out, len, remap_flags, ops); } EXPORT_SYMBOL_GPL(dax_remap_file_range_prep); + +void dax_page_free(struct page *page) +{ + wake_up_var(page); +} +EXPORT_SYMBOL_GPL(dax_page_free);
diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c
index 1a52a51..6e90a4b 100644
--- a/fs/fuse/virtio_fs.c
+++ b/fs/fuse/virtio_fs.c@@ -909,6 +909,10 @@ static void virtio_fs_cleanup_dax(void *data) DEFINE_FREE(cleanup_dax, struct dax_dev *, if (!IS_ERR_OR_NULL(_T)) virtio_fs_cleanup_dax(_T)) +static const struct dev_pagemap_ops fsdax_pagemap_ops = { + .page_free = dax_page_free, +}; + static int virtio_fs_setup_dax(struct virtio_device *vdev, struct virtio_fs *fs) { struct dax_device *dax_dev __free(cleanup_dax) = NULL;
@@ -948,6 +952,7 @@ static int virtio_fs_setup_dax(struct virtio_device *vdev, struct virtio_fs *fs) return -ENOMEM; pgmap->type = MEMORY_DEVICE_FS_DAX; + pgmap->ops = &fsdax_pagemap_ops; /* Ideally we would directly use the PCI BAR resource but * devm_memremap_pages() wants its own copy in pgmap. So
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 773dfc4..adbafc8 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h@@ -213,6 +213,7 @@ int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero, int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, const struct iomap_ops *ops); +void dax_page_free(struct page *page); static inline int dax_wait_page_idle(struct page *page, void (cb)(struct inode *), struct inode *inode)
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