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> Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx> == Hi Andrew, As Dan mentioned[1], the rc should be initialized. I fixed it and resend this patch. [1] https://lore.kernel.org/linux-fsdevel/Yp8FUZnO64Qvyx5G@kili/ --- fs/dax.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index b59b864017ad..7a8eb1e30a1b 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1026,20 +1026,22 @@ int dax_writeback_mapping_range(struct address_space *mapping, } EXPORT_SYMBOL_GPL(dax_writeback_mapping_range); -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) { pgoff_t pgoff = dax_iomap_pgoff(iomap, pos); - int id, rc; + int id, rc = 0; long length; id = dax_read_lock(); length = dax_direct_access(iomap->dax_dev, pgoff, PHYS_PFN(size), - DAX_ACCESS, NULL, pfnp); + DAX_ACCESS, kaddr, pfnp); if (length < 0) { rc = length; goto out; } + if (!pfnp) + goto out_check_addr; rc = -EINVAL; if (PFN_PHYS(length) < size) goto out; @@ -1049,6 +1051,12 @@ 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; @@ -1456,7 +1464,7 @@ 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); -- 2.36.1
