On Wed, Sep 15, 2021 at 06:44:54PM +0800, Shiyang Ruan wrote:
> 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@xxxxxxxxxxx>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> Reviewed-by: Ritesh Harjani <riteshh@xxxxxxxxxxxxx>
> Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Could've sworn I reviewed this a few revisions ago...
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
--D
> ---
> fs/dax.c | 16 ++++++++++++----
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/fs/dax.c b/fs/dax.c
> index 4e3e5a283a91..8b482a58acae 100644
> --- a/fs/dax.c
> +++ b/fs/dax.c
> @@ -1010,8 +1010,8 @@ static sector_t dax_iomap_sector(const struct iomap *iomap, loff_t pos)
> return (iomap->addr + (pos & PAGE_MASK) - iomap->offset) >> 9;
> }
>
> -static int dax_iomap_pfn(const struct iomap *iomap, loff_t pos, size_t size,
> - pfn_t *pfnp)
> +static int dax_iomap_direct_access(const 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;
> @@ -1023,11 +1023,13 @@ static int dax_iomap_pfn(const 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)
> + goto out_check_addr;
> rc = -EINVAL;
> if (PFN_PHYS(length) < size)
> goto out;
> @@ -1037,6 +1039,12 @@ static int dax_iomap_pfn(const 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;
> @@ -1401,7 +1409,7 @@ static vm_fault_t dax_fault_iter(struct vm_fault *vmf,
> return pmd ? VM_FAULT_FALLBACK : VM_FAULT_SIGBUS;
> }
>
> - err = dax_iomap_pfn(&iter->iomap, pos, size, &pfn);
> + err = dax_iomap_direct_access(&iter->iomap, pos, size, NULL, &pfn);
> if (err)
> return pmd ? VM_FAULT_FALLBACK : dax_fault_return(err);
>
> --
> 2.33.0
>
>
>
