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dax: Remove i_mmap_lock protection 

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@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
hifive-unleashed-5.1
Jan Kara 2016-05-12 18:29:20 +02:00 committed by Ross Zwisler
parent bc2466e425
commit 4d9a2c8746
2 changed files with 5 additions and 21 deletions
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24
fs/dax.c
View File

@ -798,29 +798,19 @@ 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);
}
/**
@ -1058,8 +1048,6 @@ 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;
@ -1148,8 +1136,6 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
}
out:
i_mmap_unlock_read(mapping);
return result;
fallback:

2
mm/memory.c
View File

@ -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);