The patch titled
shmem_getpage return page locked
has been added to the -mm tree. Its filename is
shmem_getpage-return-page-locked.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: shmem_getpage return page locked
From: Hugh Dickins <hugh@xxxxxxxxxxx>
In the new aops, write_begin is supposed to return the page locked: though
I've seen no ill effects, that's been overlooked in the case of
shmem_write_begin, and should be fixed. Then shmem_write_end must unlock the
page: do so _after_ updating i_size, as we found to be important in other
filesystems (though since shmem pages don't go the usual writeback route, they
never suffered from that corruption).
For shmem_write_begin to return the page locked, we need shmem_getpage to
return the page locked in SGP_WRITE case as well as SGP_CACHE case: let's
simplify the interface and return it locked even when SGP_READ.
Signed-off-by: Hugh Dickins <hugh@xxxxxxxxxxx>
Acked-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/shmem.c | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)
diff -puN mm/shmem.c~shmem_getpage-return-page-locked mm/shmem.c
--- a/mm/shmem.c~shmem_getpage-return-page-locked
+++ a/mm/shmem.c
@@ -729,6 +729,8 @@ static int shmem_notify_change(struct de
(void) shmem_getpage(inode,
attr->ia_size>>PAGE_CACHE_SHIFT,
&page, SGP_READ, NULL);
+ if (page)
+ unlock_page(page);
}
/*
* Reset SHMEM_PAGEIN flag so that shmem_truncate can
@@ -1270,12 +1272,7 @@ repeat:
SetPageUptodate(filepage);
}
done:
- if (*pagep != filepage) {
- *pagep = filepage;
- if (sgp != SGP_CACHE)
- unlock_page(filepage);
-
- }
+ *pagep = filepage;
return 0;
failed:
@@ -1453,12 +1450,13 @@ shmem_write_end(struct file *file, struc
{
struct inode *inode = mapping->host;
+ if (pos + copied > inode->i_size)
+ i_size_write(inode, pos + copied);
+
+ unlock_page(page);
set_page_dirty(page);
page_cache_release(page);
- if (pos+copied > inode->i_size)
- i_size_write(inode, pos+copied);
-
return copied;
}
@@ -1513,6 +1511,7 @@ shmem_file_write(struct file *file, cons
if (err)
break;
+ unlock_page(page);
left = bytes;
if (PageHighMem(page)) {
volatile unsigned char dummy;
@@ -1594,6 +1593,8 @@ static void do_shmem_file_read(struct fi
desc->error = 0;
break;
}
+ if (page)
+ unlock_page(page);
/*
* We must evaluate after, since reads (unlike writes)
@@ -1883,6 +1884,7 @@ static int shmem_symlink(struct inode *d
iput(inode);
return error;
}
+ unlock_page(page);
inode->i_op = &shmem_symlink_inode_operations;
kaddr = kmap_atomic(page, KM_USER0);
memcpy(kaddr, symname, len);
@@ -1910,6 +1912,8 @@ static void *shmem_follow_link(struct de
struct page *page = NULL;
int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL);
nd_set_link(nd, res ? ERR_PTR(res) : kmap(page));
+ if (page)
+ unlock_page(page);
return page;
}
_
Patches currently in -mm which might be from hugh@xxxxxxxxxxx are
origin.patch
exportfs-add-fid-type.patch
exportfs-add-new-methods.patch
shmem-new-export-ops.patch
exportfs-remove-old-methods.patch
exportfs-make-struct-export_operations-const.patch
exportfs-update-documentation.patch
fix-mprotect-vma_wants_writenotify-prot.patch
swapin_readahead-excise-numa-bogosity.patch
swapin_readahead-move-and-rearrange-args.patch
swapin-needs-gfp_mask-for-loop-on-tmpfs.patch
shmem-sgp_quick-and-sgp_fault-redundant.patch
shmem_getpage-return-page-locked.patch
shmem_file_write-is-redundant.patch
swapin-fix-valid_swaphandles-defect.patch
memory-controller-memory-accounting-v7.patch
prio_tree-debugging-patch.patch
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