diff options
| author | Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> | 2019-03-09 17:37:21 +0530 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2019-03-13 13:58:46 -0700 |
| commit | 11cf9d863dcb583345723b0ed72173348761e9c0 (patch) | |
| tree | bad3b78bca6faa12ff8d3087e20aba15a6e1bad7 /fs/dax.c | |
| parent | e4b3448bc346fedf36db64124a664a959995b085 (diff) | |
| download | lwn-11cf9d863dcb583345723b0ed72173348761e9c0.tar.gz lwn-11cf9d863dcb583345723b0ed72173348761e9c0.zip | |
fs/dax: Deposit pagetable even when installing zero page
Architectures like ppc64 use the deposited page table to store hardware
page table slot information. Make sure we deposit a page table when
using zero page at the pmd level for hash.
Without this we hit
Unable to handle kernel paging request for data at address 0x00000000
Faulting instruction address: 0xc000000000082a74
Oops: Kernel access of bad area, sig: 11 [#1]
....
NIP [c000000000082a74] __hash_page_thp+0x224/0x5b0
LR [c0000000000829a4] __hash_page_thp+0x154/0x5b0
Call Trace:
hash_page_mm+0x43c/0x740
do_hash_page+0x2c/0x3c
copy_from_iter_flushcache+0xa4/0x4a0
pmem_copy_from_iter+0x2c/0x50 [nd_pmem]
dax_copy_from_iter+0x40/0x70
dax_iomap_actor+0x134/0x360
iomap_apply+0xfc/0x1b0
dax_iomap_rw+0xac/0x130
ext4_file_write_iter+0x254/0x460 [ext4]
__vfs_write+0x120/0x1e0
vfs_write+0xd8/0x220
SyS_write+0x6c/0x110
system_call+0x3c/0x130
Fixes: b5beae5e224f ("powerpc/pseries: Add driver for PAPR SCM regions")
Cc: <stable@vger.kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'fs/dax.c')
| -rw-r--r-- | fs/dax.c | 15 |
1 files changed, 15 insertions, 0 deletions
@@ -33,6 +33,7 @@ #include <linux/sizes.h> #include <linux/mmu_notifier.h> #include <linux/iomap.h> +#include <asm/pgalloc.h> #include "internal.h" #define CREATE_TRACE_POINTS @@ -1407,7 +1408,9 @@ static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf, { struct address_space *mapping = vmf->vma->vm_file->f_mapping; unsigned long pmd_addr = vmf->address & PMD_MASK; + struct vm_area_struct *vma = vmf->vma; struct inode *inode = mapping->host; + pgtable_t pgtable = NULL; struct page *zero_page; spinlock_t *ptl; pmd_t pmd_entry; @@ -1422,12 +1425,22 @@ static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf, *entry = dax_insert_entry(xas, mapping, vmf, *entry, pfn, DAX_PMD | DAX_ZERO_PAGE, false); + if (arch_needs_pgtable_deposit()) { + pgtable = pte_alloc_one(vma->vm_mm); + if (!pgtable) + return VM_FAULT_OOM; + } + ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); if (!pmd_none(*(vmf->pmd))) { spin_unlock(ptl); goto fallback; } + if (pgtable) { + pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable); + mm_inc_nr_ptes(vma->vm_mm); + } pmd_entry = mk_pmd(zero_page, vmf->vma->vm_page_prot); pmd_entry = pmd_mkhuge(pmd_entry); set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry); @@ -1436,6 +1449,8 @@ static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf, return VM_FAULT_NOPAGE; fallback: + if (pgtable) + pte_free(vma->vm_mm, pgtable); trace_dax_pmd_load_hole_fallback(inode, vmf, zero_page, *entry); return VM_FAULT_FALLBACK; } |