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scm: lower SCM_MAX_FD

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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.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2010-11-23 14:09:15 +00:00 committed by David S. Miller
parent 456b61bca8
commit bba14de987
2 changed files with 9 additions and 6 deletions
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5
include/net/scm.h
View file

@ -10,11 +10,12 @@
/* Well, we should have at least one descriptor open /* Well, we should have at least one descriptor open
* to accept passed FDs 8) * to accept passed FDs 8)
*/ */
#define SCM_MAX_FD 255 #define SCM_MAX_FD 253
struct scm_fp_list { struct scm_fp_list {
struct list_head list; struct list_head list;
int count; short count;
short max;
struct file *fp[SCM_MAX_FD]; struct file *fp[SCM_MAX_FD];
}; };

10
net/core/scm.c
View file

@ -79,10 +79,11 @@ static int scm_fp_copy(struct cmsghdr *cmsg, struct scm_fp_list **fplp)
return -ENOMEM; return -ENOMEM;
*fplp = fpl; *fplp = fpl;
fpl->count = 0; fpl->count = 0;
fpl->max = SCM_MAX_FD;
} }
fpp = &fpl->fp[fpl->count]; fpp = &fpl->fp[fpl->count];
if (fpl->count + num > SCM_MAX_FD) if (fpl->count + num > fpl->max)
return -EINVAL; return -EINVAL;
/* /*
@ -331,11 +332,12 @@ struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl)
if (!fpl) if (!fpl)
return NULL; 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) { if (new_fpl) {
for (i=fpl->count-1; i>=0; i--) for (i = 0; i < fpl->count; i++)
get_file(fpl->fp[i]); get_file(fpl->fp[i]);
memcpy(new_fpl, fpl, sizeof(*fpl)); new_fpl->max = new_fpl->count;
} }
return new_fpl; return new_fpl;
} }