diff options
author | Roland Dreier <rdreier@cisco.com> | 2006-07-14 07:24:23 (GMT) |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-07-15 04:53:54 (GMT) |
commit | c259cc281255bdb30ceba190bfd7f37e3ae3fc85 (patch) | |
tree | 395028450ca91c441eab243186f5015fe5d6e3d4 /lib | |
parent | 6fbe82a952790c634ea6035c223a01a81377daf1 (diff) | |
download | linux-fsl-qoriq-c259cc281255bdb30ceba190bfd7f37e3ae3fc85.tar.xz |
[PATCH] Convert idr's internal locking to _irqsave variant
Currently, the code in lib/idr.c uses a bare spin_lock(&idp->lock) to do
internal locking. This is a nasty trap for code that might call idr
functions from different contexts; for example, it seems perfectly
reasonable to call idr_get_new() from process context and idr_remove() from
interrupt context -- but with the current locking this would lead to a
potential deadlock.
The simplest fix for this is to just convert the idr locking to use
spin_lock_irqsave().
In particular, this fixes a very complicated locking issue detected by
lockdep, involving the ib_ipoib driver's priv->lock and dev->_xmit_lock,
which get involved with the ib_sa module's query_idr.lock.
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Zach Brown <zach.brown@oracle.com>,
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'lib')
-rw-r--r-- | lib/idr.c | 16 |
1 files changed, 10 insertions, 6 deletions
@@ -38,14 +38,15 @@ static kmem_cache_t *idr_layer_cache; static struct idr_layer *alloc_layer(struct idr *idp) { struct idr_layer *p; + unsigned long flags; - spin_lock(&idp->lock); + spin_lock_irqsave(&idp->lock, flags); if ((p = idp->id_free)) { idp->id_free = p->ary[0]; idp->id_free_cnt--; p->ary[0] = NULL; } - spin_unlock(&idp->lock); + spin_unlock_irqrestore(&idp->lock, flags); return(p); } @@ -59,12 +60,14 @@ static void __free_layer(struct idr *idp, struct idr_layer *p) static void free_layer(struct idr *idp, struct idr_layer *p) { + unsigned long flags; + /* * Depends on the return element being zeroed. */ - spin_lock(&idp->lock); + spin_lock_irqsave(&idp->lock, flags); __free_layer(idp, p); - spin_unlock(&idp->lock); + spin_unlock_irqrestore(&idp->lock, flags); } /** @@ -168,6 +171,7 @@ static int idr_get_new_above_int(struct idr *idp, void *ptr, int starting_id) { struct idr_layer *p, *new; int layers, v, id; + unsigned long flags; id = starting_id; build_up: @@ -191,14 +195,14 @@ build_up: * The allocation failed. If we built part of * the structure tear it down. */ - spin_lock(&idp->lock); + spin_lock_irqsave(&idp->lock, flags); for (new = p; p && p != idp->top; new = p) { p = p->ary[0]; new->ary[0] = NULL; new->bitmap = new->count = 0; __free_layer(idp, new); } - spin_unlock(&idp->lock); + spin_unlock_irqrestore(&idp->lock, flags); return -1; } new->ary[0] = p; |