From: Eric Dumazet <eric.duma...@gmail.com>
-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
If you see a problem with using this for longterm, please comment.
-------------------
commit bba14de98753cb6599a2dae0e520714b2153522d upstream.
Lower SCM_MAX_FD from 255 to 253 so that allocations for scm_fp_list are
halved. (commit f8d570a4 added two pointers in this structure)
scm_fp_dup() should not copy whole structure (and trigger kmemcheck
warnings), but only the used part. While we are at it, only allocate
needed size.
Signed-off-by: Eric Dumazet <eric.duma...@gmail.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Paul Gortmaker <paul.gortma...@windriver.com>
---
include/net/scm.h | 5 +++--
net/core/scm.c | 10 ++++++----
2 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/include/net/scm.h b/include/net/scm.h
index 8360e47..8b5cccd 100644
--- a/include/net/scm.h
+++ b/include/net/scm.h
@@ -10,11 +10,12 @@
/* Well, we should have at least one descriptor open
* to accept passed FDs 8)
*/
-#define SCM_MAX_FD 255
+#define SCM_MAX_FD 253
struct scm_fp_list {
struct list_head list;
- int count;
+ short count;
+ short max;
struct file *fp[SCM_MAX_FD];
};
diff --git a/net/core/scm.c b/net/core/scm.c
index b88f6f9..ddc0448 100644
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -79,10 +79,11 @@ static int scm_fp_copy(struct cmsghdr *cmsg, struct
scm_fp_list **fplp)
return -ENOMEM;
*fplp = fpl;
fpl->count = 0;
+ fpl->max = SCM_MAX_FD;
}
fpp = &fpl->fp[fpl->count];
- if (fpl->count + num > SCM_MAX_FD)
+ if (fpl->count + num > fpl->max)
return -EINVAL;
/*
@@ -303,11 +304,12 @@ struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl)
if (!fpl)
return NULL;
- new_fpl = kmalloc(sizeof(*fpl), GFP_KERNEL);
+ new_fpl = kmemdup(fpl, offsetof(struct scm_fp_list, fp[fpl->count]),
+ GFP_KERNEL);
if (new_fpl) {
- for (i=fpl->count-1; i>=0; i--)
+ for (i = 0; i < fpl->count; i++)
get_file(fpl->fp[i]);
- memcpy(new_fpl, fpl, sizeof(*fpl));
+ new_fpl->max = new_fpl->count;
}
return new_fpl;
}
--
1.7.12.rc2
--
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