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authorRoss Lagerwall <ross.lagerwall@citrix.com>2019-01-08 18:30:56 +0000
committerSteve French <stfrench@microsoft.com>2019-01-11 07:14:40 -0600
commit92a8109e4d3a34fb6b115c9098b51767dc933444 (patch)
treebf25221c25731b147937ae58efdf15c54be3e19a /fs/cifs/file.c
parent15bc77f94e9f0e3cfd6972f3b84bb7aaa4c36b1b (diff)
cifs: Limit memory used by lock request calls to a page
The code tries to allocate a contiguous buffer with a size supplied by the server (maxBuf). This could fail if memory is fragmented since it results in high order allocations for commonly used server implementations. It is also wasteful since there are probably few locks in the usual case. Limit the buffer to be no larger than a page to avoid memory allocation failures due to fragmentation. Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com> Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs/cifs/file.c')
-rw-r--r--fs/cifs/file.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index e3e3a7550205..673f948e4760 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1140,6 +1140,10 @@ cifs_push_mandatory_locks(struct cifsFileInfo *cfile)
return -EINVAL;
}
+ BUILD_BUG_ON(sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE) >
+ PAGE_SIZE);
+ max_buf = min_t(unsigned int, max_buf - sizeof(struct smb_hdr),
+ PAGE_SIZE);
max_num = (max_buf - sizeof(struct smb_hdr)) /
sizeof(LOCKING_ANDX_RANGE);
buf = kcalloc(max_num, sizeof(LOCKING_ANDX_RANGE), GFP_KERNEL);
@@ -1478,6 +1482,10 @@ cifs_unlock_range(struct cifsFileInfo *cfile, struct file_lock *flock,
if (!max_buf)
return -EINVAL;
+ BUILD_BUG_ON(sizeof(struct smb_hdr) + sizeof(LOCKING_ANDX_RANGE) >
+ PAGE_SIZE);
+ max_buf = min_t(unsigned int, max_buf - sizeof(struct smb_hdr),
+ PAGE_SIZE);
max_num = (max_buf - sizeof(struct smb_hdr)) /
sizeof(LOCKING_ANDX_RANGE);
buf = kcalloc(max_num, sizeof(LOCKING_ANDX_RANGE), GFP_KERNEL);