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| author | Robin Holt <holt@sgi.com> | 2011-01-12 17:00:01 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-01-13 08:03:12 -0800 |
| commit | 52bd19f7691b2ea6433aef0ef94c08c57efd7e79 (patch) | |
| tree | daaa39ee774fb4fe56ca61247eb930ed4f6e1ef1 /fs/eventpoll.c | |
| parent | 65329bf46bf9ddc37845c9a6823a8e8022d305b9 (diff) | |
| download | lwn-52bd19f7691b2ea6433aef0ef94c08c57efd7e79.tar.gz lwn-52bd19f7691b2ea6433aef0ef94c08c57efd7e79.zip | |
epoll: convert max_user_watches to long
On a 16TB machine, max_user_watches has an integer overflow. Convert it
to use a long and handle the associated fallout.
Signed-off-by: Robin Holt <holt@sgi.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/eventpoll.c')
| -rw-r--r-- | fs/eventpoll.c | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 8cf07242067d..cc8a9b7d6064 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -217,7 +217,7 @@ struct ep_send_events_data { * Configuration options available inside /proc/sys/fs/epoll/ */ /* Maximum number of epoll watched descriptors, per user */ -static int max_user_watches __read_mostly; +static long max_user_watches __read_mostly; /* * This mutex is used to serialize ep_free() and eventpoll_release_file(). @@ -240,16 +240,18 @@ static struct kmem_cache *pwq_cache __read_mostly; #include <linux/sysctl.h> -static int zero; +static long zero; +static long long_max = LONG_MAX; ctl_table epoll_table[] = { { .procname = "max_user_watches", .data = &max_user_watches, - .maxlen = sizeof(int), + .maxlen = sizeof(max_user_watches), .mode = 0644, - .proc_handler = proc_dointvec_minmax, + .proc_handler = proc_doulongvec_minmax, .extra1 = &zero, + .extra2 = &long_max, }, { } }; @@ -561,7 +563,7 @@ static int ep_remove(struct eventpoll *ep, struct epitem *epi) /* At this point it is safe to free the eventpoll item */ kmem_cache_free(epi_cache, epi); - atomic_dec(&ep->user->epoll_watches); + atomic_long_dec(&ep->user->epoll_watches); return 0; } @@ -898,11 +900,12 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event, { int error, revents, pwake = 0; unsigned long flags; + long user_watches; struct epitem *epi; struct ep_pqueue epq; - if (unlikely(atomic_read(&ep->user->epoll_watches) >= - max_user_watches)) + user_watches = atomic_long_read(&ep->user->epoll_watches); + if (unlikely(user_watches >= max_user_watches)) return -ENOSPC; if (!(epi = kmem_cache_alloc(epi_cache, GFP_KERNEL))) return -ENOMEM; @@ -966,7 +969,7 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event, spin_unlock_irqrestore(&ep->lock, flags); - atomic_inc(&ep->user->epoll_watches); + atomic_long_inc(&ep->user->epoll_watches); /* We have to call this outside the lock */ if (pwake) @@ -1426,6 +1429,7 @@ static int __init eventpoll_init(void) */ max_user_watches = (((si.totalram - si.totalhigh) / 25) << PAGE_SHIFT) / EP_ITEM_COST; + BUG_ON(max_user_watches < 0); /* Initialize the structure used to perform safe poll wait head wake ups */ ep_nested_calls_init(&poll_safewake_ncalls); |