fsdax: factor out a dax_fault_actor() helper
The core logic in the two dax page fault functions is similar. So, move the logic into a common helper function. Also, to facilitate the addition of new features, such as CoW, switch-case is no longer used to handle different iomap types. Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
This commit is contained in:
Shiyang Ruan
Darrick J. Wong
parent
55f81639a7
commit
c2436190e4
297
fs/dax.c
297
fs/dax.c
@ -1066,6 +1066,66 @@ static vm_fault_t dax_load_hole(struct xa_state *xas,
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return ret;
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}
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#ifdef CONFIG_FS_DAX_PMD
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static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf,
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struct iomap *iomap, void **entry)
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{
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struct address_space *mapping = vmf->vma->vm_file->f_mapping;
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unsigned long pmd_addr = vmf->address & PMD_MASK;
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struct vm_area_struct *vma = vmf->vma;
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struct inode *inode = mapping->host;
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pgtable_t pgtable = NULL;
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struct page *zero_page;
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spinlock_t *ptl;
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pmd_t pmd_entry;
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pfn_t pfn;
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zero_page = mm_get_huge_zero_page(vmf->vma->vm_mm);
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if (unlikely(!zero_page))
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goto fallback;
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pfn = page_to_pfn_t(zero_page);
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*entry = dax_insert_entry(xas, mapping, vmf, *entry, pfn,
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DAX_PMD | DAX_ZERO_PAGE, false);
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if (arch_needs_pgtable_deposit()) {
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pgtable = pte_alloc_one(vma->vm_mm);
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if (!pgtable)
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return VM_FAULT_OOM;
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}
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ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd);
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if (!pmd_none(*(vmf->pmd))) {
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spin_unlock(ptl);
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goto fallback;
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}
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if (pgtable) {
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pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable);
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mm_inc_nr_ptes(vma->vm_mm);
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}
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pmd_entry = mk_pmd(zero_page, vmf->vma->vm_page_prot);
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pmd_entry = pmd_mkhuge(pmd_entry);
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set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry);
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spin_unlock(ptl);
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trace_dax_pmd_load_hole(inode, vmf, zero_page, *entry);
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return VM_FAULT_NOPAGE;
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fallback:
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if (pgtable)
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pte_free(vma->vm_mm, pgtable);
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trace_dax_pmd_load_hole_fallback(inode, vmf, zero_page, *entry);
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return VM_FAULT_FALLBACK;
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}
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#else
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static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf,
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struct iomap *iomap, void **entry)
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{
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return VM_FAULT_FALLBACK;
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}
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#endif /* CONFIG_FS_DAX_PMD */
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s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap)
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{
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sector_t sector = iomap_sector(iomap, pos & PAGE_MASK);
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@ -1302,6 +1362,63 @@ static vm_fault_t dax_fault_cow_page(struct vm_fault *vmf, struct iomap *iomap,
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return ret;
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}
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/**
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* dax_fault_actor - Common actor to handle pfn insertion in PTE/PMD fault.
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* @vmf: vm fault instance
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* @pfnp: pfn to be returned
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* @xas: the dax mapping tree of a file
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* @entry: an unlocked dax entry to be inserted
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* @pmd: distinguish whether it is a pmd fault
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* @flags: iomap flags
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* @iomap: from iomap_begin()
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* @srcmap: from iomap_begin(), not equal to iomap if it is a CoW
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*/
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static vm_fault_t dax_fault_actor(struct vm_fault *vmf, pfn_t *pfnp,
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struct xa_state *xas, void **entry, bool pmd,
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unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
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{
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struct address_space *mapping = vmf->vma->vm_file->f_mapping;
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size_t size = pmd ? PMD_SIZE : PAGE_SIZE;
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loff_t pos = (loff_t)xas->xa_index << PAGE_SHIFT;
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bool write = vmf->flags & FAULT_FLAG_WRITE;
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bool sync = dax_fault_is_synchronous(flags, vmf->vma, iomap);
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unsigned long entry_flags = pmd ? DAX_PMD : 0;
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int err = 0;
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pfn_t pfn;
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/* if we are reading UNWRITTEN and HOLE, return a hole. */
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if (!write &&
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(iomap->type == IOMAP_UNWRITTEN || iomap->type == IOMAP_HOLE)) {
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if (!pmd)
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return dax_load_hole(xas, mapping, entry, vmf);
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return dax_pmd_load_hole(xas, vmf, iomap, entry);
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}
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if (iomap->type != IOMAP_MAPPED) {
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WARN_ON_ONCE(1);
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return pmd ? VM_FAULT_FALLBACK : VM_FAULT_SIGBUS;
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}
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err = dax_iomap_pfn(iomap, pos, size, &pfn);
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if (err)
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return pmd ? VM_FAULT_FALLBACK : dax_fault_return(err);
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*entry = dax_insert_entry(xas, mapping, vmf, *entry, pfn, entry_flags,
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write && !sync);
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if (sync)
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return dax_fault_synchronous_pfnp(pfnp, pfn);
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/* insert PMD pfn */
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if (pmd)
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return vmf_insert_pfn_pmd(vmf, pfn, write);
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/* insert PTE pfn */
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if (write)
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return vmf_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn);
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return vmf_insert_mixed(vmf->vma, vmf->address, pfn);
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}
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static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
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int *iomap_errp, const struct iomap_ops *ops)
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{
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@ -1309,17 +1426,14 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
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struct address_space *mapping = vma->vm_file->f_mapping;
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XA_STATE(xas, &mapping->i_pages, vmf->pgoff);
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struct inode *inode = mapping->host;
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unsigned long vaddr = vmf->address;
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loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT;
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struct iomap iomap = { .type = IOMAP_HOLE };
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struct iomap srcmap = { .type = IOMAP_HOLE };
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unsigned flags = IOMAP_FAULT;
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int error, major = 0;
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int error;
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bool write = vmf->flags & FAULT_FLAG_WRITE;
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bool sync;
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vm_fault_t ret = 0;
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vm_fault_t ret = 0, major = 0;
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void *entry;
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pfn_t pfn;
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trace_dax_pte_fault(inode, vmf, ret);
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/*
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@ -1365,8 +1479,8 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
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goto unlock_entry;
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}
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if (WARN_ON_ONCE(iomap.offset + iomap.length < pos + PAGE_SIZE)) {
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error = -EIO; /* fs corruption? */
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goto error_finish_iomap;
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ret = VM_FAULT_SIGBUS; /* fs corruption? */
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goto finish_iomap;
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}
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if (vmf->cow_page) {
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@ -1374,49 +1488,19 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
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goto finish_iomap;
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}
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sync = dax_fault_is_synchronous(flags, vma, &iomap);
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switch (iomap.type) {
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case IOMAP_MAPPED:
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if (iomap.flags & IOMAP_F_NEW) {
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count_vm_event(PGMAJFAULT);
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count_memcg_event_mm(vma->vm_mm, PGMAJFAULT);
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major = VM_FAULT_MAJOR;
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}
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error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn);
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if (error < 0)
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goto error_finish_iomap;
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entry = dax_insert_entry(&xas, mapping, vmf, entry, pfn,
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0, write && !sync);
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if (sync) {
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ret = dax_fault_synchronous_pfnp(pfnp, pfn);
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goto finish_iomap;
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}
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trace_dax_insert_mapping(inode, vmf, entry);
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if (write)
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ret = vmf_insert_mixed_mkwrite(vma, vaddr, pfn);
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else
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ret = vmf_insert_mixed(vma, vaddr, pfn);
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ret = dax_fault_actor(vmf, pfnp, &xas, &entry, false, flags,
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&iomap, &srcmap);
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if (ret == VM_FAULT_SIGBUS)
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goto finish_iomap;
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case IOMAP_UNWRITTEN:
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case IOMAP_HOLE:
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if (!write) {
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ret = dax_load_hole(&xas, mapping, &entry, vmf);
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goto finish_iomap;
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}
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fallthrough;
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default:
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WARN_ON_ONCE(1);
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error = -EIO;
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break;
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/* read/write MAPPED, CoW UNWRITTEN */
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if (iomap.flags & IOMAP_F_NEW) {
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count_vm_event(PGMAJFAULT);
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count_memcg_event_mm(vma->vm_mm, PGMAJFAULT);
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major = VM_FAULT_MAJOR;
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}
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error_finish_iomap:
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ret = dax_fault_return(error);
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finish_iomap:
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finish_iomap:
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if (ops->iomap_end) {
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int copied = PAGE_SIZE;
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@ -1430,66 +1514,14 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
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*/
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ops->iomap_end(inode, pos, PAGE_SIZE, copied, flags, &iomap);
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}
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unlock_entry:
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unlock_entry:
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dax_unlock_entry(&xas, entry);
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out:
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out:
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trace_dax_pte_fault_done(inode, vmf, ret);
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return ret | major;
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}
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#ifdef CONFIG_FS_DAX_PMD
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static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf,
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struct iomap *iomap, void **entry)
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{
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struct address_space *mapping = vmf->vma->vm_file->f_mapping;
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unsigned long pmd_addr = vmf->address & PMD_MASK;
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struct vm_area_struct *vma = vmf->vma;
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struct inode *inode = mapping->host;
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pgtable_t pgtable = NULL;
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struct page *zero_page;
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spinlock_t *ptl;
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pmd_t pmd_entry;
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pfn_t pfn;
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zero_page = mm_get_huge_zero_page(vmf->vma->vm_mm);
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if (unlikely(!zero_page))
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goto fallback;
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pfn = page_to_pfn_t(zero_page);
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*entry = dax_insert_entry(xas, mapping, vmf, *entry, pfn,
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DAX_PMD | DAX_ZERO_PAGE, false);
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if (arch_needs_pgtable_deposit()) {
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pgtable = pte_alloc_one(vma->vm_mm);
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if (!pgtable)
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return VM_FAULT_OOM;
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}
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ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd);
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if (!pmd_none(*(vmf->pmd))) {
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spin_unlock(ptl);
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goto fallback;
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}
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if (pgtable) {
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pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable);
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mm_inc_nr_ptes(vma->vm_mm);
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}
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pmd_entry = mk_pmd(zero_page, vmf->vma->vm_page_prot);
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pmd_entry = pmd_mkhuge(pmd_entry);
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set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry);
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spin_unlock(ptl);
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trace_dax_pmd_load_hole(inode, vmf, zero_page, *entry);
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return VM_FAULT_NOPAGE;
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fallback:
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if (pgtable)
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pte_free(vma->vm_mm, pgtable);
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trace_dax_pmd_load_hole_fallback(inode, vmf, zero_page, *entry);
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return VM_FAULT_FALLBACK;
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}
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static bool dax_fault_check_fallback(struct vm_fault *vmf, struct xa_state *xas,
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pgoff_t max_pgoff)
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{
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@ -1530,17 +1562,15 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
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struct address_space *mapping = vma->vm_file->f_mapping;
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XA_STATE_ORDER(xas, &mapping->i_pages, vmf->pgoff, PMD_ORDER);
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bool write = vmf->flags & FAULT_FLAG_WRITE;
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bool sync;
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unsigned int iomap_flags = (write ? IOMAP_WRITE : 0) | IOMAP_FAULT;
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unsigned int flags = (write ? IOMAP_WRITE : 0) | IOMAP_FAULT;
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struct inode *inode = mapping->host;
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vm_fault_t result = VM_FAULT_FALLBACK;
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vm_fault_t ret = VM_FAULT_FALLBACK;
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struct iomap iomap = { .type = IOMAP_HOLE };
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struct iomap srcmap = { .type = IOMAP_HOLE };
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pgoff_t max_pgoff;
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void *entry;
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loff_t pos;
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int error;
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pfn_t pfn;
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/*
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* Check whether offset isn't beyond end of file now. Caller is
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@ -1552,7 +1582,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
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trace_dax_pmd_fault(inode, vmf, max_pgoff, 0);
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if (xas.xa_index >= max_pgoff) {
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result = VM_FAULT_SIGBUS;
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ret = VM_FAULT_SIGBUS;
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goto out;
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}
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@ -1567,7 +1597,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
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*/
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entry = grab_mapping_entry(&xas, mapping, PMD_ORDER);
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if (xa_is_internal(entry)) {
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result = xa_to_internal(entry);
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ret = xa_to_internal(entry);
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goto fallback;
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}
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@ -1579,7 +1609,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
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*/
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if (!pmd_none(*vmf->pmd) && !pmd_trans_huge(*vmf->pmd) &&
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!pmd_devmap(*vmf->pmd)) {
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result = 0;
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ret = 0;
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goto unlock_entry;
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}
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@ -1589,49 +1619,21 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
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* to look up our filesystem block.
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*/
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pos = (loff_t)xas.xa_index << PAGE_SHIFT;
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error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap,
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&srcmap);
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error = ops->iomap_begin(inode, pos, PMD_SIZE, flags, &iomap, &srcmap);
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if (error)
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goto unlock_entry;
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if (iomap.offset + iomap.length < pos + PMD_SIZE)
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goto finish_iomap;
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sync = dax_fault_is_synchronous(iomap_flags, vma, &iomap);
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ret = dax_fault_actor(vmf, pfnp, &xas, &entry, true, flags,
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&iomap, &srcmap);
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switch (iomap.type) {
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case IOMAP_MAPPED:
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error = dax_iomap_pfn(&iomap, pos, PMD_SIZE, &pfn);
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if (error < 0)
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goto finish_iomap;
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entry = dax_insert_entry(&xas, mapping, vmf, entry, pfn,
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DAX_PMD, write && !sync);
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if (sync) {
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result = dax_fault_synchronous_pfnp(pfnp, pfn);
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goto finish_iomap;
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}
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trace_dax_pmd_insert_mapping(inode, vmf, PMD_SIZE, pfn, entry);
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result = vmf_insert_pfn_pmd(vmf, pfn, write);
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break;
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case IOMAP_UNWRITTEN:
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case IOMAP_HOLE:
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if (WARN_ON_ONCE(write))
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break;
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result = dax_pmd_load_hole(&xas, vmf, &iomap, &entry);
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break;
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default:
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WARN_ON_ONCE(1);
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break;
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}
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finish_iomap:
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finish_iomap:
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if (ops->iomap_end) {
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int copied = PMD_SIZE;
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if (result == VM_FAULT_FALLBACK)
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if (ret == VM_FAULT_FALLBACK)
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copied = 0;
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/*
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* The fault is done by now and there's no way back (other
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@ -1639,19 +1641,18 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
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* Just ignore error from ->iomap_end since we cannot do much
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* with it.
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*/
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ops->iomap_end(inode, pos, PMD_SIZE, copied, iomap_flags,
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&iomap);
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ops->iomap_end(inode, pos, PMD_SIZE, copied, flags, &iomap);
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}
|
||||
unlock_entry:
|
||||
unlock_entry:
|
||||
dax_unlock_entry(&xas, entry);
|
||||
fallback:
|
||||
if (result == VM_FAULT_FALLBACK) {
|
||||
fallback:
|
||||
if (ret == VM_FAULT_FALLBACK) {
|
||||
split_huge_pmd(vma, vmf->pmd, vmf->address);
|
||||
count_vm_event(THP_FAULT_FALLBACK);
|
||||
}
|
||||
out:
|
||||
trace_dax_pmd_fault_done(inode, vmf, max_pgoff, result);
|
||||
return result;
|
||||
trace_dax_pmd_fault_done(inode, vmf, max_pgoff, ret);
|
||||
return ret;
|
||||
}
|
||||
#else
|
||||
static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
|
||||
|
||||
Loading…
Reference in New Issue
Block a user