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.f...@fujitsu.com> Reviewed-by: Christoph Hellwig <h...@lst.de> Reviewed-by: Ritesh Harjani <rite...@linux.ibm.com> Reviewed-by: Dan Williams <dan.j.willi...@intel.com> --- 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