The patch titled
Subject: fsdax: update dax_insert_entry() calling convention to return an error
has been added to the -mm mm-unstable branch. Its filename is
fsdax-update-dax_insert_entry-calling-convention-to-return-an-error.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/fsdax-update-dax_insert_entry-calling-convention-to-return-an-error.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Dan Williams <dan.j.williams@xxxxxxxxx>
Subject: fsdax: update dax_insert_entry() calling convention to return an error
Date: Fri, 14 Oct 2022 16:57:43 -0700
In preparation for teaching dax_insert_entry() to take live @pgmap
references, enable it to return errors. Given the observation that all
callers overwrite the passed in entry with the return value, just update
@entry in place and convert the return code to a vm_fault_t status.
Link: https://lkml.kernel.org/r/166579186334.2236710.388332274317019999.stgit@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: "Darrick J. Wong" <djwong@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Ben Skeggs <bskeggs@xxxxxxxxxx>
Cc: "Christian König" <christian.koenig@xxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: David Airlie <airlied@xxxxxxxx>
Cc: Felix Kuehling <Felix.Kuehling@xxxxxxx>
Cc: Jerome Glisse <jglisse@xxxxxxxxxx>
Cc: Karol Herbst <kherbst@xxxxxxxxxx>
Cc: kernel test robot <lkp@xxxxxxxxx>
Cc: Lyude Paul <lyude@xxxxxxxxxx>
Cc: "Pan, Xinhui" <Xinhui.Pan@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/dax.c | 28 ++++++++++++++++++++--------
1 file changed, 20 insertions(+), 8 deletions(-)
--- a/fs/dax.c~fsdax-update-dax_insert_entry-calling-convention-to-return-an-error
+++ a/fs/dax.c
@@ -907,14 +907,15 @@ static bool dax_fault_is_cow(const struc
* already in the tree, we will skip the insertion and just dirty the PMD as
* appropriate.
*/
-static void *dax_insert_entry(struct xa_state *xas, struct vm_fault *vmf,
- const struct iomap_iter *iter, void *entry, pfn_t pfn,
- unsigned long flags)
+static vm_fault_t dax_insert_entry(struct xa_state *xas, struct vm_fault *vmf,
+ const struct iomap_iter *iter, void **pentry,
+ pfn_t pfn, unsigned long flags)
{
struct address_space *mapping = vmf->vma->vm_file->f_mapping;
void *new_entry = dax_make_entry(pfn, flags);
bool dirty = !dax_fault_is_synchronous(iter, vmf->vma);
bool cow = dax_fault_is_cow(iter);
+ void *entry = *pentry;
if (dirty)
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
@@ -960,7 +961,9 @@ static void *dax_insert_entry(struct xa_
xas_set_mark(xas, PAGECACHE_TAG_TOWRITE);
xas_unlock_irq(xas);
- return entry;
+
+ *pentry = entry;
+ return 0;
}
static int dax_writeback_one(struct xa_state *xas, struct dax_device *dax_dev,
@@ -1206,9 +1209,12 @@ static vm_fault_t dax_load_hole(struct x
pfn_t pfn = pfn_to_pfn_t(my_zero_pfn(vaddr));
vm_fault_t ret;
- *entry = dax_insert_entry(xas, vmf, iter, *entry, pfn, DAX_ZERO_PAGE);
+ ret = dax_insert_entry(xas, vmf, iter, entry, pfn, DAX_ZERO_PAGE);
+ if (ret)
+ goto out;
ret = vmf_insert_mixed(vmf->vma, vaddr, pfn);
+out:
trace_dax_load_hole(inode, vmf, ret);
return ret;
}
@@ -1225,6 +1231,7 @@ static vm_fault_t dax_pmd_load_hole(stru
struct page *zero_page;
spinlock_t *ptl;
pmd_t pmd_entry;
+ vm_fault_t ret;
pfn_t pfn;
zero_page = mm_get_huge_zero_page(vmf->vma->vm_mm);
@@ -1233,8 +1240,10 @@ static vm_fault_t dax_pmd_load_hole(stru
goto fallback;
pfn = page_to_pfn_t(zero_page);
- *entry = dax_insert_entry(xas, vmf, iter, *entry, pfn,
- DAX_PMD | DAX_ZERO_PAGE);
+ ret = dax_insert_entry(xas, vmf, iter, entry, pfn,
+ DAX_PMD | DAX_ZERO_PAGE);
+ if (ret)
+ return ret;
if (arch_needs_pgtable_deposit()) {
pgtable = pte_alloc_one(vma->vm_mm);
@@ -1590,6 +1599,7 @@ static vm_fault_t dax_fault_iter(struct
bool write = iter->flags & IOMAP_WRITE;
unsigned long entry_flags = pmd ? DAX_PMD : 0;
int err = 0, id;
+ vm_fault_t ret;
pfn_t pfn;
void *kaddr;
@@ -1616,8 +1626,10 @@ static vm_fault_t dax_fault_iter(struct
return pmd ? VM_FAULT_FALLBACK : dax_fault_return(err);
}
- *entry = dax_insert_entry(xas, vmf, iter, *entry, pfn, entry_flags);
+ ret = dax_insert_entry(xas, vmf, iter, entry, pfn, entry_flags);
dax_read_unlock(id);
+ if (ret)
+ return ret;
if (write &&
srcmap->type != IOMAP_HOLE && srcmap->addr != iomap->addr) {
_
Patches currently in -mm which might be from dan.j.williams@xxxxxxxxx are
fsdax-wait-on-page-not-page-_refcount.patch
fsdax-use-dax_page_idle-to-document-dax-busy-page-checking.patch
fsdax-include-unmapped-inodes-for-page-idle-detection.patch
fsdax-introduce-dax_zap_mappings.patch
fsdax-wait-for-pinned-pages-during-truncate_inode_pages_final.patch
fsdax-validate-dax-layouts-broken-before-truncate.patch
fsdax-hold-dax-lock-over-mapping-insertion.patch
fsdax-update-dax_insert_entry-calling-convention-to-return-an-error.patch
fsdax-rework-for_each_mapped_pfn-to-dax_for_each_folio.patch
fsdax-introduce-pgmap_request_folios.patch
fsdax-rework-dax_insert_entry-calling-convention.patch
fsdax-cleanup-dax_associate_entry.patch
devdax-minor-warning-fixups.patch
devdax-fix-sparse-lock-imbalance-warning.patch
libnvdimm-pmem-support-pmem-block-devices-without-dax.patch
devdax-move-address_space-helpers-to-the-dax-core.patch
devdax-sparse-fixes-for-xarray-locking.patch
devdax-sparse-fixes-for-vmfault_t-dax-entry-conversions.patch
devdax-sparse-fixes-for-vm_fault_t-in-tracepoints.patch
devdax-add-pud-support-to-the-dax-mapping-infrastructure.patch
devdax-use-dax_insert_entry-dax_delete_mapping_entry.patch
mm-memremap_pages-replace-zone_device_page_init-with-pgmap_request_folios.patch
mm-memremap_pages-initialize-all-zone_device-pages-to-start-at-refcount-0.patch
mm-meremap_pages-delete-put_devmap_managed_page_refs.patch
mm-gup-drop-dax-pgmap-accounting.patch
