[PATCH v2 3/3] fsdax: Output address in dax_iomap_pfn() and rename it

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(a)fujitsu.com&gt; Reviewed-by: Christoph Hellwig <hch(a)lst.de&gt; Reviewed-by: Ritesh Harjani <riteshh(a)linux.ibm.com&gt; --- fs/dax.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index 6dea1fc11b46..8d7e4e2cc0fb 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) + 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; @@ -1389,7 +1397,7 @@ static vm_fault_t dax_fault_actor(struct vm_fault *vmf, pfn_t *pfnp, return pmd ? VM_FAULT_FALLBACK : VM_FAULT_SIGBUS; } - err = dax_iomap_pfn(iomap, pos, size, &pfn); + err = dax_iomap_direct_access(iomap, pos, size, NULL, &pfn); if (err) return pmd ? VM_FAULT_FALLBACK : dax_fault_return(err); -- 2.31.0