diff options
author | Jeff Layton <jlayton@redhat.com> | 2013-04-29 23:21:16 (GMT) |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-04-30 01:28:41 (GMT) |
commit | 3e6628c4b347a558965041290c5a92791dd4c741 (patch) | |
tree | 7f437ed24761f467b61c0a401fc8d6a6ca7fee3a /include/linux | |
parent | 27cf10e133c393f39399137b028c7b24d64ca06e (diff) | |
download | linux-fsl-qoriq-3e6628c4b347a558965041290c5a92791dd4c741.tar.xz |
idr: introduce idr_alloc_cyclic()
As Tejun points out, there are several users of the IDR facility that
attempt to use it in a cyclic fashion. These users are likely to see
-ENOSPC errors after the counter wraps one or more times however.
This patchset adds a new idr_alloc_cyclic routine and converts several
of these users to it. Many of these users are in obscure parts of the
kernel, and I don't have a good way to test some of them. The change is
pretty straightforward though, so hopefully it won't be an issue.
There is one other cyclic user of idr_alloc that I didn't touch in
ipc/util.c. That one is doing some strange stuff that I didn't quite
understand, but it looks like it should probably be converted later
somehow.
This patch:
Thus spake Tejun Heo:
Ooh, BTW, the cyclic allocation is broken. It's prone to -ENOSPC
after the first wraparound. There are several cyclic users in the
kernel and I think it probably would be best to implement cyclic
support in idr.
This patch does that by adding new idr_alloc_cyclic function that such
users in the kernel can use. With this, there's no need for a caller to
keep track of the last value used as that's now tracked internally. This
should prevent the ENOSPC problems that can hit when the "last allocated"
counter exceeds INT_MAX.
Later patches will convert existing cyclic users to the new interface.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Jack Morgenstein <jackm@dev.mellanox.co.il>
Cc: John McCutchan <john@johnmccutchan.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Robert Love <rlove@rlove.org>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Sridhar Samudrala <sri@us.ibm.com>
Cc: Steve Wise <swise@opengridcomputing.com>
Cc: Tom Tucker <tom@opengridcomputing.com>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux')
-rw-r--r-- | include/linux/idr.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/idr.h b/include/linux/idr.h index 2640c7e..a470ac3 100644 --- a/include/linux/idr.h +++ b/include/linux/idr.h @@ -42,6 +42,7 @@ struct idr { struct idr_layer *id_free; int layers; /* only valid w/o concurrent changes */ int id_free_cnt; + int cur; /* current pos for cyclic allocation */ spinlock_t lock; }; @@ -75,6 +76,7 @@ struct idr { void *idr_find_slowpath(struct idr *idp, int id); void idr_preload(gfp_t gfp_mask); int idr_alloc(struct idr *idp, void *ptr, int start, int end, gfp_t gfp_mask); +int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask); int idr_for_each(struct idr *idp, int (*fn)(int id, void *p, void *data), void *data); void *idr_get_next(struct idr *idp, int *nextid); |