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MFC r262006,r262328:

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r262006:
  Fix M_FILEDESC leak in fdgrowtable() introduced in r244510.
  fdgrowtable() now only reallocates fd_map when necessary.
 r262328:
  Style.

Approved by:	bapt (mentor, implicit)
This commit is contained in:
bdrewery 2014-03-02 16:25:56 +00:00
parent 1e9cbfb2bd
commit ee7a8407e1
1 changed files with 21 additions and 11 deletions
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32
sys/kern/kern_descrip.c
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@ -1522,7 +1522,7 @@ fdgrowtable(struct filedesc *fdp, int nfd)
return;
/*
* Allocate a new table and map. We need enough space for the
* Allocate a new table. We need enough space for the
* file entries themselves and the struct freetable we will use
* when we decommission the table and place it on the freelist.
* We place the struct freetable in the middle so we don't have
@ -1530,16 +1530,22 @@ fdgrowtable(struct filedesc *fdp, int nfd)
*/
ntable = malloc(nnfiles * sizeof(ntable[0]) + sizeof(struct freetable),
M_FILEDESC, M_ZERO | M_WAITOK);
nmap = malloc(NDSLOTS(nnfiles) * NDSLOTSIZE, M_FILEDESC,
M_ZERO | M_WAITOK);
/* copy the old data over and point at the new tables */
memcpy(ntable, otable, onfiles * sizeof(*otable));
memcpy(nmap, omap, NDSLOTS(onfiles) * sizeof(*omap));
/* update the pointers and counters */
fdp->fd_ofiles = ntable;
fdp->fd_map = nmap;
/*
* Allocate a new map only if the old is not large enough. It will
* grow at a slower rate than the table as it can map more
* entries than the table can hold.
*/
if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) {
nmap = malloc(NDSLOTS(nnfiles) * NDSLOTSIZE, M_FILEDESC,
M_ZERO | M_WAITOK);
/* copy over the old data and update the pointer */
memcpy(nmap, omap, NDSLOTS(onfiles) * sizeof(*omap));
fdp->fd_map = nmap;
}
/*
* In order to have a valid pattern for fget_unlocked()
@ -1555,8 +1561,6 @@ fdgrowtable(struct filedesc *fdp, int nfd)
* reference entries within it. Instead, place it on a freelist
* which will be processed when the struct filedesc is released.
*
* Do, however, free the old map.
*
* Note that if onfiles == NDFILE, we're dealing with the original
* static allocation contained within (struct filedesc0 *)fdp,
* which must not be freed.
@ -1566,8 +1570,14 @@ fdgrowtable(struct filedesc *fdp, int nfd)
fdp0 = (struct filedesc0 *)fdp;
ft->ft_table = otable;
SLIST_INSERT_HEAD(&fdp0->fd_free, ft, ft_next);
free(omap, M_FILEDESC);
}
/*
* The map does not have the same possibility of threads still
* holding references to it. So always free it as long as it
* does not reference the original static allocation.
*/
if (NDSLOTS(onfiles) > NDSLOTS(NDFILE))
free(omap, M_FILEDESC);
}
/*