virtiofs: keep a list of free dax memory ranges (45f2348e) · Commits · 戴 / test

fs/fuse/dax.c

+90 −1

Original line number	Diff line number	Diff line
		@@ -7,20 +7,104 @@
		#include "fuse_i.h"

		#include <linux/dax.h>
		#include <linux/pfn_t.h>

		/* Default memory range size, 2MB */
		#define FUSE_DAX_SHIFT 21
		#define FUSE_DAX_SZ (1 << FUSE_DAX_SHIFT)
		#define FUSE_DAX_PAGES (FUSE_DAX_SZ / PAGE_SIZE)

		/** Translation information for file offsets to DAX window offsets */
		struct fuse_dax_mapping {
		/* Will connect in fcd->free_ranges to keep track of free memory */
		struct list_head list;

		/** Position in DAX window */
		u64 window_offset;

		/** Length of mapping, in bytes */
		loff_t length;
		};

		struct fuse_conn_dax {
		/* DAX device */
		struct dax_device *dev;

		/* DAX Window Free Ranges */
		long nr_free_ranges;
		struct list_head free_ranges;
		};

		static void fuse_free_dax_mem_ranges(struct list_head *mem_list)
		{
		struct fuse_dax_mapping range, temp;

		/* Free All allocated elements */
		list_for_each_entry_safe(range, temp, mem_list, list) {
		list_del(&range->list);
		kfree(range);
		}
		}

		void fuse_dax_conn_free(struct fuse_conn *fc)
		{
		if (fc->dax) {
		fuse_free_dax_mem_ranges(&fc->dax->free_ranges);
		kfree(fc->dax);
		}
		}

		static int fuse_dax_mem_range_init(struct fuse_conn_dax *fcd)
		{
		long nr_pages, nr_ranges;
		void *kaddr;
		pfn_t pfn;
		struct fuse_dax_mapping *range;
		int ret, id;
		size_t dax_size = -1;
		unsigned long i;

		INIT_LIST_HEAD(&fcd->free_ranges);
		id = dax_read_lock();
		nr_pages = dax_direct_access(fcd->dev, 0, PHYS_PFN(dax_size), &kaddr,
		&pfn);
		dax_read_unlock(id);
		if (nr_pages < 0) {
		pr_debug("dax_direct_access() returned %ld\n", nr_pages);
		return nr_pages;
		}

		nr_ranges = nr_pages/FUSE_DAX_PAGES;
		pr_debug("%s: dax mapped %ld pages. nr_ranges=%ld\n",
		__func__, nr_pages, nr_ranges);

		for (i = 0; i < nr_ranges; i++) {
		range = kzalloc(sizeof(struct fuse_dax_mapping), GFP_KERNEL);
		ret = -ENOMEM;
		if (!range)
		goto out_err;

		/* TODO: This offset only works if virtio-fs driver is not
		* having some memory hidden at the beginning. This needs
		* better handling
		*/
		range->window_offset = i * FUSE_DAX_SZ;
		range->length = FUSE_DAX_SZ;
		list_add_tail(&range->list, &fcd->free_ranges);
		}

		fcd->nr_free_ranges = nr_ranges;
		return 0;
		out_err:
		/* Free All allocated elements */
		fuse_free_dax_mem_ranges(&fcd->free_ranges);
		return ret;
		}

		int fuse_dax_conn_alloc(struct fuse_conn fc, struct dax_device dax_dev)
		{
		struct fuse_conn_dax *fcd;
		int err;

		if (!dax_dev)
		return 0;
		@@ -30,6 +114,11 @@ int fuse_dax_conn_alloc(struct fuse_conn fc, struct dax_device dax_dev)
		return -ENOMEM;

		fcd->dev = dax_dev;
		err = fuse_dax_mem_range_init(fcd);
		if (err) {
		kfree(fcd);
		return err;
		}

		fc->dax = fcd;
		return 0;

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