Re: [PATCH 1/7] fsdax: Output address in dax_iomap_pfn() and rename it

Xiaoguang Wang
2021-02-22T07:47:10Z

hi,

> Add address output in dax_iomap_pfn() in order to perform a memcpy() in
> CoW case. Since this function both output address and pfn, rename it to
> dax_iomap_direct_access().
>
> Signed-off-by: Shiyang Ruan <ruansy.fnst@cn.fujitsu.com>
> ---
> fs/dax.c | 20 +++++++++++++++-----
> 1 file changed, 15 insertions(+), 5 deletions(-)
>
> diff --git a/fs/dax.c b/fs/dax.c
> index 5b47834f2e1b..b012b2db7ba2 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -998,8 +998,8 @@ static sector_t dax_iomap_sector(struct iomap *iomap, loff_t pos)
> return (iomap->addr + (pos & PAGE_MASK) - iomap->offset) >> 9;
> }
>
> -static int dax_iomap_pfn(struct iomap *iomap, loff_t pos, size_t size,
> - pfn_t *pfnp)
> +static int dax_iomap_direct_access(struct iomap *iomap, loff_t pos, size_t size,
> + void **kaddr, pfn_t *pfnp)
> {
> const sector_t sector = dax_iomap_sector(iomap, pos);
> pgoff_t pgoff;
> @@ -1011,11 +1011,13 @@ static int dax_iomap_pfn(struct iomap *iomap, loff_t pos, size_t size,
> return rc;
> id = dax_read_lock();
> length = dax_direct_access(iomap->dax_dev, pgoff, PHYS_PFN(size),
> - NULL, pfnp);
> + kaddr, pfnp);
> if (length < 0) {
> rc = length;
> goto out;
> }
> + if (!pfnp)
Should this be "if (!*pfnp)"?

Regards,
Xiaoguang Wang
> + goto out_check_addr;
> rc = -EINVAL;
> if (PFN_PHYS(length) < size)
> goto out;
> @@ -1025,6 +1027,12 @@ static int dax_iomap_pfn(struct iomap *iomap, loff_t pos, size_t size,
> if (length > 1 && !pfn_t_devmap(*pfnp))
> goto out;
> rc = 0;
> +
> +out_check_addr:
> + if (!kaddr)
> + goto out;
> + if (!*kaddr)
> + rc = -EFAULT;
> out:
> dax_read_unlock(id);
> return rc;
> @@ -1348,7 +1356,8 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
> count_memcg_event_mm(vma->vm_mm, PGMAJFAULT);
> major = VM_FAULT_MAJOR;
> }
> - error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn);
> + error = dax_iomap_direct_access(&iomap, pos, PAGE_SIZE,
> + NULL, &pfn);
> if (error < 0)
> goto error_finish_iomap;
>
> @@ -1566,7 +1575,8 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
>
> switch (iomap.type) {
> case IOMAP_MAPPED:
> - error = dax_iomap_pfn(&iomap, pos, PMD_SIZE, &pfn);
> + error = dax_iomap_direct_access(&iomap, pos, PMD_SIZE,
> + NULL, &pfn);
> if (error < 0)
> goto finish_iomap;