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authorSouptick Joarder <jrdr.linux@gmail.com>2018-06-08 03:04:29 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-06-08 03:34:33 +0300
commitab77dab46210bb630e06c6803c5d84074bacd351 (patch)
tree1b0c7f6899d1438d11fa3fab5353318539aafd96 /fs/dax.c
parent3036bc45364f98515a2c446d7fac2c34dcfbeff4 (diff)
downloadlinux-ab77dab46210bb630e06c6803c5d84074bacd351.tar.xz
fs/dax.c: use new return type vm_fault_t
Use new return type vm_fault_t for fault handler. For now, this is just documenting that the function returns a VM_FAULT value rather than an errno. Once all instances are converted, vm_fault_t will become a distinct type. commit 1c8f422059ae ("mm: change return type to vm_fault_t") There was an existing bug inside dax_load_hole() if vm_insert_mixed had failed to allocate a page table, we'd return VM_FAULT_NOPAGE instead of VM_FAULT_OOM. With new vmf_insert_mixed() this issue is addressed. vm_insert_mixed_mkwrite has inefficiency when it returns an error value, driver has to convert it to vm_fault_t type. With new vmf_insert_mixed_mkwrite() this limitation will be addressed. Link: http://lkml.kernel.org/r/20180510181121.GA15239@jordon-HP-15-Notebook-PC Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/dax.c')
-rw-r--r--fs/dax.c78
1 files changed, 37 insertions, 41 deletions
diff --git a/fs/dax.c b/fs/dax.c
index aa86d9f971a4..08656a2f2aa6 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -905,12 +905,12 @@ out:
* If this page is ever written to we will re-fault and change the mapping to
* point to real DAX storage instead.
*/
-static int dax_load_hole(struct address_space *mapping, void *entry,
+static vm_fault_t dax_load_hole(struct address_space *mapping, void *entry,
struct vm_fault *vmf)
{
struct inode *inode = mapping->host;
unsigned long vaddr = vmf->address;
- int ret = VM_FAULT_NOPAGE;
+ vm_fault_t ret = VM_FAULT_NOPAGE;
struct page *zero_page;
void *entry2;
pfn_t pfn;
@@ -929,7 +929,7 @@ static int dax_load_hole(struct address_space *mapping, void *entry,
goto out;
}
- vm_insert_mixed(vmf->vma, vaddr, pfn);
+ ret = vmf_insert_mixed(vmf->vma, vaddr, pfn);
out:
trace_dax_load_hole(inode, vmf, ret);
return ret;
@@ -1112,7 +1112,7 @@ dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
}
EXPORT_SYMBOL_GPL(dax_iomap_rw);
-static int dax_fault_return(int error)
+static vm_fault_t dax_fault_return(int error)
{
if (error == 0)
return VM_FAULT_NOPAGE;
@@ -1132,7 +1132,7 @@ static bool dax_fault_is_synchronous(unsigned long flags,
&& (iomap->flags & IOMAP_F_DIRTY);
}
-static int dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
+static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
int *iomap_errp, const struct iomap_ops *ops)
{
struct vm_area_struct *vma = vmf->vma;
@@ -1145,18 +1145,18 @@ static int dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
int error, major = 0;
bool write = vmf->flags & FAULT_FLAG_WRITE;
bool sync;
- int vmf_ret = 0;
+ vm_fault_t ret = 0;
void *entry;
pfn_t pfn;
- trace_dax_pte_fault(inode, vmf, vmf_ret);
+ trace_dax_pte_fault(inode, vmf, ret);
/*
* Check whether offset isn't beyond end of file now. Caller is supposed
* to hold locks serializing us with truncate / punch hole so this is
* a reliable test.
*/
if (pos >= i_size_read(inode)) {
- vmf_ret = VM_FAULT_SIGBUS;
+ ret = VM_FAULT_SIGBUS;
goto out;
}
@@ -1165,7 +1165,7 @@ static int dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
entry = grab_mapping_entry(mapping, vmf->pgoff, 0);
if (IS_ERR(entry)) {
- vmf_ret = dax_fault_return(PTR_ERR(entry));
+ ret = dax_fault_return(PTR_ERR(entry));
goto out;
}
@@ -1176,7 +1176,7 @@ static int dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
* retried.
*/
if (pmd_trans_huge(*vmf->pmd) || pmd_devmap(*vmf->pmd)) {
- vmf_ret = VM_FAULT_NOPAGE;
+ ret = VM_FAULT_NOPAGE;
goto unlock_entry;
}
@@ -1189,7 +1189,7 @@ static int dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
if (iomap_errp)
*iomap_errp = error;
if (error) {
- vmf_ret = dax_fault_return(error);
+ ret = dax_fault_return(error);
goto unlock_entry;
}
if (WARN_ON_ONCE(iomap.offset + iomap.length < pos + PAGE_SIZE)) {
@@ -1219,9 +1219,9 @@ static int dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
goto error_finish_iomap;
__SetPageUptodate(vmf->cow_page);
- vmf_ret = finish_fault(vmf);
- if (!vmf_ret)
- vmf_ret = VM_FAULT_DONE_COW;
+ ret = finish_fault(vmf);
+ if (!ret)
+ ret = VM_FAULT_DONE_COW;
goto finish_iomap;
}
@@ -1257,23 +1257,20 @@ static int dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
goto error_finish_iomap;
}
*pfnp = pfn;
- vmf_ret = VM_FAULT_NEEDDSYNC | major;
+ ret = VM_FAULT_NEEDDSYNC | major;
goto finish_iomap;
}
trace_dax_insert_mapping(inode, vmf, entry);
if (write)
- error = vm_insert_mixed_mkwrite(vma, vaddr, pfn);
+ ret = vmf_insert_mixed_mkwrite(vma, vaddr, pfn);
else
- error = vm_insert_mixed(vma, vaddr, pfn);
+ ret = vmf_insert_mixed(vma, vaddr, pfn);
- /* -EBUSY is fine, somebody else faulted on the same PTE */
- if (error == -EBUSY)
- error = 0;
- break;
+ goto finish_iomap;
case IOMAP_UNWRITTEN:
case IOMAP_HOLE:
if (!write) {
- vmf_ret = dax_load_hole(mapping, entry, vmf);
+ ret = dax_load_hole(mapping, entry, vmf);
goto finish_iomap;
}
/*FALLTHRU*/
@@ -1284,12 +1281,12 @@ static int dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
}
error_finish_iomap:
- vmf_ret = dax_fault_return(error) | major;
+ ret = dax_fault_return(error);
finish_iomap:
if (ops->iomap_end) {
int copied = PAGE_SIZE;
- if (vmf_ret & VM_FAULT_ERROR)
+ if (ret & VM_FAULT_ERROR)
copied = 0;
/*
* The fault is done by now and there's no way back (other
@@ -1302,12 +1299,12 @@ static int dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
unlock_entry:
put_locked_mapping_entry(mapping, vmf->pgoff);
out:
- trace_dax_pte_fault_done(inode, vmf, vmf_ret);
- return vmf_ret;
+ trace_dax_pte_fault_done(inode, vmf, ret);
+ return ret | major;
}
#ifdef CONFIG_FS_DAX_PMD
-static int dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap,
+static vm_fault_t dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap,
void *entry)
{
struct address_space *mapping = vmf->vma->vm_file->f_mapping;
@@ -1348,7 +1345,7 @@ fallback:
return VM_FAULT_FALLBACK;
}
-static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
+static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
const struct iomap_ops *ops)
{
struct vm_area_struct *vma = vmf->vma;
@@ -1358,7 +1355,7 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
bool sync;
unsigned int iomap_flags = (write ? IOMAP_WRITE : 0) | IOMAP_FAULT;
struct inode *inode = mapping->host;
- int result = VM_FAULT_FALLBACK;
+ vm_fault_t result = VM_FAULT_FALLBACK;
struct iomap iomap = { 0 };
pgoff_t max_pgoff, pgoff;
void *entry;
@@ -1509,7 +1506,7 @@ out:
return result;
}
#else
-static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
+static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
const struct iomap_ops *ops)
{
return VM_FAULT_FALLBACK;
@@ -1529,7 +1526,7 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
* has done all the necessary locking for page fault to proceed
* successfully.
*/
-int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
+vm_fault_t dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
pfn_t *pfnp, int *iomap_errp, const struct iomap_ops *ops)
{
switch (pe_size) {
@@ -1553,14 +1550,14 @@ EXPORT_SYMBOL_GPL(dax_iomap_fault);
* DAX file. It takes care of marking corresponding radix tree entry as dirty
* as well.
*/
-static int dax_insert_pfn_mkwrite(struct vm_fault *vmf,
+static vm_fault_t dax_insert_pfn_mkwrite(struct vm_fault *vmf,
enum page_entry_size pe_size,
pfn_t pfn)
{
struct address_space *mapping = vmf->vma->vm_file->f_mapping;
void *entry, **slot;
pgoff_t index = vmf->pgoff;
- int vmf_ret, error;
+ vm_fault_t ret;
xa_lock_irq(&mapping->i_pages);
entry = get_unlocked_mapping_entry(mapping, index, &slot);
@@ -1579,21 +1576,20 @@ static int dax_insert_pfn_mkwrite(struct vm_fault *vmf,
xa_unlock_irq(&mapping->i_pages);
switch (pe_size) {
case PE_SIZE_PTE:
- error = vm_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn);
- vmf_ret = dax_fault_return(error);
+ ret = vmf_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn);
break;
#ifdef CONFIG_FS_DAX_PMD
case PE_SIZE_PMD:
- vmf_ret = vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd,
+ ret = vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd,
pfn, true);
break;
#endif
default:
- vmf_ret = VM_FAULT_FALLBACK;
+ ret = VM_FAULT_FALLBACK;
}
put_locked_mapping_entry(mapping, index);
- trace_dax_insert_pfn_mkwrite(mapping->host, vmf, vmf_ret);
- return vmf_ret;
+ trace_dax_insert_pfn_mkwrite(mapping->host, vmf, ret);
+ return ret;
}
/**
@@ -1606,8 +1602,8 @@ static int dax_insert_pfn_mkwrite(struct vm_fault *vmf,
* stored persistently on the media and handles inserting of appropriate page
* table entry.
*/
-int dax_finish_sync_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
- pfn_t pfn)
+vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf,
+ enum page_entry_size pe_size, pfn_t pfn)
{
int err;
loff_t start = ((loff_t)vmf->pgoff) << PAGE_SHIFT;