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| author | Al Viro <viro@zeniv.linux.org.uk> | 2015-11-17 01:07:57 -0500 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2015-12-08 22:41:36 -0500 |
| commit | 21fc61c73c3903c4c312d0802da01ec2b323d174 (patch) | |
| tree | a26c29e3fbb766f00b023724e9e5b8b9bba9b879 /mm | |
| parent | aa80deab33a8fb180e718f5e45514db19aade165 (diff) | |
| download | lwn-21fc61c73c3903c4c312d0802da01ec2b323d174.tar.gz lwn-21fc61c73c3903c4c312d0802da01ec2b323d174.zip | |
don't put symlink bodies in pagecache into highmem
kmap() in page_follow_link_light() needed to go - allowing to hold
an arbitrary number of kmaps for long is a great way to deadlocking
the system.
new helper (inode_nohighmem(inode)) needs to be used for pagecache
symlinks inodes; done for all in-tree cases. page_follow_link_light()
instrumented to yell about anything missed.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/shmem.c | 9 |
1 files changed, 3 insertions, 6 deletions
diff --git a/mm/shmem.c b/mm/shmem.c index 9187eee4128b..64bf5acb49fe 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2444,7 +2444,6 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s int len; struct inode *inode; struct page *page; - char *kaddr; struct shmem_inode_info *info; len = strlen(symname) + 1; @@ -2483,9 +2482,8 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s } inode->i_mapping->a_ops = &shmem_aops; inode->i_op = &shmem_symlink_inode_operations; - kaddr = kmap_atomic(page); - memcpy(kaddr, symname, len); - kunmap_atomic(kaddr); + inode_nohighmem(inode); + memcpy(page_address(page), symname, len); SetPageUptodate(page); set_page_dirty(page); unlock_page(page); @@ -2506,13 +2504,12 @@ static const char *shmem_follow_link(struct dentry *dentry, void **cookie) return ERR_PTR(error); unlock_page(page); *cookie = page; - return kmap(page); + return page_address(page); } static void shmem_put_link(struct inode *unused, void *cookie) { struct page *page = cookie; - kunmap(page); mark_page_accessed(page); page_cache_release(page); } |