Currently faults are protected against truncate by filesystem specific
i_mmap_sem and page lock in case of hole page. Cow faults are protected
DAX radix tree entry locking. So there's no need for i_mmap_lock in DAX
code. Remove it.
Reviewed-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
fs/dax.c | 24 +++++-------------------
mm/memory.c | 2 --
2 files changed, 5 insertions(+), 21 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index d907bf8b07a0..5a34f086b4ca 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -826,29 +826,19 @@ static int dax_insert_mapping(struct address_space *mapping,
.sector = to_sector(bh, mapping->host),
.size = bh->b_size,
};
- int error;
void *ret;
void *entry = *entryp;
- i_mmap_lock_read(mapping);
-
- if (dax_map_atomic(bdev, &dax) < 0) {
- error = PTR_ERR(dax.addr);
- goto out;
- }
+ if (dax_map_atomic(bdev, &dax) < 0)
+ return PTR_ERR(dax.addr);
dax_unmap_atomic(bdev, &dax);
ret = dax_insert_mapping_entry(mapping, vmf, entry, dax.sector);
- if (IS_ERR(ret)) {
- error = PTR_ERR(ret);
- goto out;
- }
+ if (IS_ERR(ret))
+ return PTR_ERR(ret);
*entryp = ret;
- error = vm_insert_mixed(vma, vaddr, dax.pfn);
- out:
- i_mmap_unlock_read(mapping);
- return error;
+ return vm_insert_mixed(vma, vaddr, dax.pfn);
}
/**
@@ -1086,8 +1076,6 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
truncate_pagecache_range(inode, lstart, lend);
}
- i_mmap_lock_read(mapping);
-
if (!write && !buffer_mapped(&bh)) {
spinlock_t *ptl;
pmd_t entry;
@@ -1179,8 +1167,6 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
}
out:
- i_mmap_unlock_read(mapping);
-
return result;
fallback:
diff --git a/mm/memory.c b/mm/memory.c
index f09cdb8d48fa..06f552504e79 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2453,8 +2453,6 @@ void unmap_mapping_range(struct address_space *mapping,
if (details.last_index < details.first_index)
details.last_index = ULONG_MAX;
-
- /* DAX uses i_mmap_lock to serialise file truncate vs page fault */
i_mmap_lock_write(mapping);
if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap)))
unmap_mapping_range_tree(&mapping->i_mmap, &details);
--
2.6.6
--
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