On 4/29/21 5:39 AM, Qiaowei Ren wrote:
> From: Jianpeng Ma <jianpeng.ma@xxxxxxxxx>
>
> This nvm pages allocator will implement the simple buddy to manage the
> nvm address space. This patch initializes this buddy for new namespace.
>
> the unit of alloc/free of the buddy is page. DAX device has their
> struct page(in dram or PMEM).
>
> struct { /* ZONE_DEVICE pages */
> /** @pgmap: Points to the hosting device page map. */
> struct dev_pagemap *pgmap;
> void *zone_device_data;
> /*
> * ZONE_DEVICE private pages are counted as being
> * mapped so the next 3 words hold the mapping, index,
> * and private fields from the source anonymous or
> * page cache page while the page is migrated to device
> * private memory.
> * ZONE_DEVICE MEMORY_DEVICE_FS_DAX pages also
> * use the mapping, index, and private fields when
> * pmem backed DAX files are mapped.
> */
> };
>
> ZONE_DEVICE pages only use pgmap. Other 4 words[16/32 bytes] don't use.
> So the second/third word will be used as 'struct list_head ' which list
> in buddy. The fourth word(that is normal struct page::index) store pgoff
> which the page-offset in the dax device. And the fifth word (that is
> normal struct page::private) store order of buddy. page_type will be used
> to store buddy flags.
>
> V9:
> -Kernel test robot report the build-in u64/u32 in init_owner_info()
> don't work for m68k arch.explicit div_u64() should be used.(Coly fix)
> -GCC report warning: Unsigned variable 'i' can't be negative so it
> is unnecessary to test it. [unsignedPositive] (Reproted-by Dan)
>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Signed-off-by: Jianpeng Ma <jianpeng.ma@xxxxxxxxx>
> Co-developed-by: Qiaowei Ren <qiaowei.ren@xxxxxxxxx>
> Signed-off-by: Qiaowei Ren <qiaowei.ren@xxxxxxxxx>
> Signed-off-by: Coly Li <colyli@xxxxxxx>
> ---
> drivers/md/bcache/nvm-pages.c | 142 +++++++++++++++++++++++++++++++-
> drivers/md/bcache/nvm-pages.h | 6 ++
> include/uapi/linux/bcache-nvm.h | 12 ++-
> 3 files changed, 153 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/md/bcache/nvm-pages.c b/drivers/md/bcache/nvm-pages.c
> index 976ab9002c17..810f65cf756a 100644
> --- a/drivers/md/bcache/nvm-pages.c
> +++ b/drivers/md/bcache/nvm-pages.c
> @@ -34,6 +34,10 @@ static void release_nvm_namespaces(struct bch_nvm_set *nvm_set)
> for (i = 0; i < nvm_set->total_namespaces_nr; i++) {
> ns = nvm_set->nss[i];
> if (ns) {
> + kvfree(ns->pages_bitmap);
> + if (ns->pgalloc_recs_bitmap)
> + bitmap_free(ns->pgalloc_recs_bitmap);
> +
> blkdev_put(ns->bdev, FMODE_READ|FMODE_WRITE|FMODE_EXEC);
> kfree(ns);
> }
> @@ -48,17 +52,122 @@ static void release_nvm_set(struct bch_nvm_set *nvm_set)
> kfree(nvm_set);
> }
>
> +static struct page *nvm_vaddr_to_page(struct bch_nvm_namespace *ns, void *addr)
> +{
> + return virt_to_page(addr);
> +}
> +
> +static void *nvm_pgoff_to_vaddr(struct bch_nvm_namespace *ns, pgoff_t pgoff)
> +{
> + return ns->kaddr + (pgoff << PAGE_SHIFT);
> +}
> +
> +static inline void remove_owner_space(struct bch_nvm_namespace *ns,
> + pgoff_t pgoff, u32 nr)
> +{
Parameter nr should be 64bit value here. rec->order is 6 bits, the
maximum value can be (1<<64)-1, 1<<rec->order may overflow 32bit width.
Myabe (correct me if I am wrong) you may change "u32 nr" to "unsigned
long order", then do something like this,
/* value range of order is [0, 1<<64) */
unsigned long total = 1 << order,
while (total > 0) {
unsigned int nr = UINT_MAX;
if (nr > total)
nr = total;
bitmap_set(ns->pages_bitmap, pgoff, nr);
pg_off += nr;
total -= nr;
};
Similar problem also exists for pg_off. The second parameter of
bitmap_set() is in unsigned int type, pgoff_t pgoff may also overflow on
it. But this is not critical, it seems the overflow may happen on order
0 with single name space is larger than 128TB for 4KB kernel page size.
Currently we don't need to worry about this.
Just my suggestion for your reference.
> + bitmap_set(ns->pages_bitmap, pgoff, nr);
> +}
> +
> static int init_owner_info(struct bch_nvm_namespace *ns)
> {
> struct bch_owner_list_head *owner_list_head = ns->sb->owner_list_head;
> + struct bch_nvm_pgalloc_recs *sys_recs;
> + int i, j, k, rc = 0;
>
> mutex_lock(&only_set->lock);
> only_set->owner_list_head = owner_list_head;
> only_set->owner_list_size = owner_list_head->size;
> only_set->owner_list_used = owner_list_head->used;
> +
> + /* remove used space */
> + remove_owner_space(ns, 0, div_u64(ns->pages_offset, ns->page_size));
> +
> + sys_recs = ns->kaddr + BCH_NVM_PAGES_SYS_RECS_HEAD_OFFSET;
> + /* suppose no hole in array */
> + for (i = 0; i < owner_list_head->used; i++) {
> + struct bch_nvm_pages_owner_head *head = &owner_list_head->heads[i];
> +
> + for (j = 0; j < BCH_NVM_PAGES_NAMESPACES_MAX; j++) {
> + struct bch_nvm_pgalloc_recs *pgalloc_recs = head->recs[j];
> + unsigned long offset = (unsigned long)ns->kaddr >> PAGE_SHIFT;
> + struct page *page;
> +
> + while (pgalloc_recs) {
> + u32 pgalloc_recs_pos = (unsigned long)(pgalloc_recs - sys_recs);
> +
> + if (memcmp(pgalloc_recs->magic, bch_nvm_pages_pgalloc_magic, 16)) {
> + pr_info("invalid bch_nvm_pages_pgalloc_magic\n");
> + rc = -EINVAL;
> + goto unlock;
> + }
> + if (memcmp(pgalloc_recs->owner_uuid, head->uuid, 16)) {
> + pr_info("invalid owner_uuid in bch_nvm_pgalloc_recs\n");
> + rc = -EINVAL;
> + goto unlock;
> + }
> + if (pgalloc_recs->owner != head) {
> + pr_info("invalid owner in bch_nvm_pgalloc_recs\n");
> + rc = -EINVAL;
> + goto unlock;
> + }
> +
> + /* recs array can has hole */
> + for (k = 0; k < pgalloc_recs->size; k++) {
> + struct bch_pgalloc_rec *rec = &pgalloc_recs->recs[k];
> +
> + if (rec->pgoff) {
> + BUG_ON(rec->pgoff <= offset);
> +
> + /* init struct page: index/private */
> + page = nvm_vaddr_to_page(ns,
> + BCH_PGOFF_TO_KVADDR(rec->pgoff));
> +
> + set_page_private(page, rec->order);
> + page->index = rec->pgoff - offset;
> +
> + remove_owner_space(ns,
> + rec->pgoff - offset,
> + 1 << rec->order);
Here is potential overflow. rec->order is 6 bit value, the maximum value
can be (1<<6)-1 = 63. But nr in remove_owner_space() is u32 ...
> + }
> + }
> + bitmap_set(ns->pgalloc_recs_bitmap, pgalloc_recs_pos, 1);
> + pgalloc_recs = pgalloc_recs->next;
> + }
> + }
> + }
> +unlock:
> mutex_unlock(&only_set->lock);
>
> - return 0;
> + return rc;
> +}
> +
> +static void init_nvm_free_space(struct bch_nvm_namespace *ns)
> +{
> + unsigned int start, end, pages;
> + int i;
> + struct page *page;
> + pgoff_t pgoff_start;
> +
> + bitmap_for_each_clear_region(ns->pages_bitmap, start, end, 0, ns->pages_total) {
> + pgoff_start = start;
> + pages = end - start;
> +
> + while (pages) {
> + for (i = BCH_MAX_ORDER - 1; i >= 0 ; i--) {
> + if ((pgoff_start % (1 << i) == 0) && (pages >= (1 << i)))
> + break;
> + }
> +
> + page = nvm_vaddr_to_page(ns, nvm_pgoff_to_vaddr(ns, pgoff_start));
> + page->index = pgoff_start;
> + set_page_private(page, i);
> + __SetPageBuddy(page);
> + list_add((struct list_head *)&page->zone_device_data, &ns->free_area[i]);
> +
> + pgoff_start += 1 << i;
> + pages -= 1 << i;
> + }
> + }
> }
>
> static bool attach_nvm_set(struct bch_nvm_namespace *ns)
> @@ -123,7 +232,7 @@ static int read_nvdimm_meta_super(struct block_device *bdev,
> struct bch_nvm_namespace *bch_register_namespace(const char *dev_path)
> {
> struct bch_nvm_namespace *ns;
> - int err;
> + int i, err;
> pgoff_t pgoff;
> char buf[BDEVNAME_SIZE];
> struct block_device *bdev;
> @@ -239,18 +348,43 @@ struct bch_nvm_namespace *bch_register_namespace(const char *dev_path)
> ns->nvm_set = only_set;
> mutex_init(&ns->lock);
>
> + ns->pages_bitmap = kvcalloc(BITS_TO_LONGS(ns->pages_total),
> + sizeof(unsigned long), GFP_KERNEL);
> + if (!ns->pages_bitmap) {
> + err = -ENOMEM;
> + goto clear_ns_nr;
> + }
> +
> + if (ns->sb->this_namespace_nr == 0) {
> + ns->pgalloc_recs_bitmap = bitmap_zalloc(BCH_MAX_PGALLOC_RECS, GFP_KERNEL);
> + if (ns->pgalloc_recs_bitmap == NULL) {
> + err = -ENOMEM;
> + goto free_pages_bitmap;
> + }
> + }
> +
> + for (i = 0; i < BCH_MAX_ORDER; i++)
> + INIT_LIST_HEAD(&ns->free_area[i]);
> +
> if (ns->sb->this_namespace_nr == 0) {
> pr_info("only first namespace contain owner info\n");
> err = init_owner_info(ns);
> if (err < 0) {
> pr_info("init_owner_info met error %d\n", err);
> - only_set->nss[ns->sb->this_namespace_nr] = NULL;
> - goto free_ns;
> + goto free_recs_bitmap;
> }
> + /* init buddy allocator */
> + init_nvm_free_space(ns);
> }
>
> kfree(path);
> return ns;
> +free_recs_bitmap:
> + bitmap_free(ns->pgalloc_recs_bitmap);
> +free_pages_bitmap:
> + kvfree(ns->pages_bitmap);
> +clear_ns_nr:
> + only_set->nss[ns->sb->this_namespace_nr] = NULL;
> free_ns:
> kfree(ns);
> bdput:
> diff --git a/drivers/md/bcache/nvm-pages.h b/drivers/md/bcache/nvm-pages.h
> index 87a0d2c46788..e08864af96a0 100644
> --- a/drivers/md/bcache/nvm-pages.h
> +++ b/drivers/md/bcache/nvm-pages.h
> @@ -16,6 +16,7 @@
> * to which owner. After reboot from power failure, they will be initialized
> * based on nvm pages superblock in NVDIMM device.
> */
> +#define BCH_MAX_ORDER 20
> struct bch_nvm_namespace {
> struct bch_nvm_pages_sb *sb;
> void *kaddr;
> @@ -27,6 +28,11 @@ struct bch_nvm_namespace {
> u64 pages_total;
> pfn_t start_pfn;
>
> + unsigned long *pages_bitmap;
> + struct list_head free_area[BCH_MAX_ORDER];
> +
> + unsigned long *pgalloc_recs_bitmap;
> +
> struct dax_device *dax_dev;
> struct block_device *bdev;
> struct bch_nvm_set *nvm_set;
> diff --git a/include/uapi/linux/bcache-nvm.h b/include/uapi/linux/bcache-nvm.h
> index 1d62e9f0d4bf..7df0934d8756 100644
> --- a/include/uapi/linux/bcache-nvm.h
> +++ b/include/uapi/linux/bcache-nvm.h
> @@ -114,6 +114,8 @@ struct bch_pgalloc_rec {
> __u64 reserved:6;
> };
>
> +#define BCH_PGOFF_TO_KVADDR(pgoff) ((void *)((unsigned long)pgoff << PAGE_SHIFT))
BCH_PGOFF_TO_KVADDR is not used inside this header, and no on-media
format involved in. It is used in nvm-pages.c, maybe it can be moved
into drivers/md/bcache/nvm-pages.h
> +
> struct bch_nvm_pgalloc_recs {
> union {
> struct {
> @@ -130,11 +132,15 @@ union {
> };
> };
>
> -#define BCH_MAX_RECS \
> - ((sizeof(struct bch_nvm_pgalloc_recs) - \
> - offsetof(struct bch_nvm_pgalloc_recs, recs)) / \
> +#define BCH_MAX_RECS \
> + ((sizeof(struct bch_nvm_pgalloc_recs) - \
> + offsetof(struct bch_nvm_pgalloc_recs, recs)) / \
> sizeof(struct bch_pgalloc_rec))
>
> +#define BCH_MAX_PGALLOC_RECS \
> + ((BCH_NVM_PAGES_OFFSET - BCH_NVM_PAGES_SYS_RECS_HEAD_OFFSET) / \
> + sizeof(struct bch_nvm_pgalloc_recs))
> +
> struct bch_nvm_pages_owner_head {
> unsigned char uuid[16];
> unsigned char label[BCH_NVM_PAGES_LABEL_SIZE];
>
The rested looks fine to me. Thanks for the great work :-)
Coly Li
