From: Tejun Heo <[email protected]> In sub_alloc(), when bitmap search fails, it goes up one level to continue search. This is done by updating the id cursor and searching the upper level again. If the cursor was at the end of the upper level, we need to go further than that. This wasn't implemented and when that happens the part of the cursor which indexes into the upper level wraps and sub_alloc() ends up searching the wrong bitmap. It allocates id which doesn't match the actual slot. This patch fixes this by restarting from the top if the search needs to go higher than one level. Signed-off-by: Tejun Heo <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- lib/idr.c | 16 ++++++++++++++-- 1 files changed, 14 insertions(+), 2 deletions(-) diff --git a/lib/idr.c b/lib/idr.c index 305117c..7b5a59c 100644 --- a/lib/idr.c +++ b/lib/idr.c @@ -100,10 +100,11 @@ static int sub_alloc(struct idr *idp, void *ptr, int *starting_id) int n, m, sh; struct idr_layer *p, *new; struct idr_layer *pa[MAX_LEVEL]; - int l, id; + int l, id, oid; long bm; id = *starting_id; + restart: p = idp->top; l = idp->layers; pa[l--] = NULL; @@ -117,12 +118,23 @@ static int sub_alloc(struct idr *idp, void *ptr, int *starting_id) if (m == IDR_SIZE) { /* no space available go back to previous layer. */ l++; + oid = id; id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; + + /* if already at the top layer, we need to grow */ if (!(p = pa[l])) { *starting_id = id; return -2; } - continue; + + /* If we need to go up one layer, continue the + * loop; otherwise, restart from the top. + */ + sh = IDR_BITS * (l + 1); + if (oid >> sh == id >> sh) + continue; + else + goto restart; } if (m != n) { sh = IDR_BITS*l; -- 1.5.2.2 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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