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authorBen Hutchings <bhutchings@solarflare.com>2011-06-24 20:26:44 +0100
committerBen Hutchings <bhutchings@solarflare.com>2011-06-25 00:43:48 +0100
commit4017dbdc14af1903dc9fcba4d08b89c02325069d (patch)
tree33c61638e1fb98ebf27f710e99f443aed9c2f738
parent22c8c9343258feda9ea9ebb9e5f8cbb727b69454 (diff)
sfc: Fix loop condition for efx_filter_search() when !for_insert
efx_filter_remove_filter() fails to remove inserted filters in some cases. For example: 1. Two filters A and B have specifications that result in an initial hash collision. 2. A is inserted first, followed by B. 3. An attempt to remove B first succeeds, but if A is removed first a subsequent attempt to remove B fails. When searching for an existing filter (!for_insert), efx_filter_search() must always continue to the maximum search depth for the given type rather than stopping at the first unused entry. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
-rw-r--r--drivers/net/sfc/filter.c41
1 files changed, 24 insertions, 17 deletions
diff --git a/drivers/net/sfc/filter.c b/drivers/net/sfc/filter.c
index f2fc2587c09d..054f0a3d45a9 100644
--- a/drivers/net/sfc/filter.c
+++ b/drivers/net/sfc/filter.c
@@ -335,28 +335,35 @@ static int efx_filter_search(struct efx_filter_table *table,
bool for_insert, int *depth_required)
{
unsigned hash, incr, filter_idx, depth, depth_max;
- struct efx_filter_spec *cmp;
hash = efx_filter_hash(key);
incr = efx_filter_increment(key);
- depth_max = (spec->priority <= EFX_FILTER_PRI_HINT ?
- FILTER_CTL_SRCH_HINT_MAX : FILTER_CTL_SRCH_MAX);
-
- for (depth = 1, filter_idx = hash & (table->size - 1);
- depth <= depth_max && test_bit(filter_idx, table->used_bitmap);
- ++depth) {
- cmp = &table->spec[filter_idx];
- if (efx_filter_equal(spec, cmp))
- goto found;
+
+ filter_idx = hash & (table->size - 1);
+ depth = 1;
+ depth_max = (for_insert ?
+ (spec->priority <= EFX_FILTER_PRI_HINT ?
+ FILTER_CTL_SRCH_HINT_MAX : FILTER_CTL_SRCH_MAX) :
+ table->search_depth[spec->type]);
+
+ for (;;) {
+ /* Return success if entry is used and matches this spec
+ * or entry is unused and we are trying to insert.
+ */
+ if (test_bit(filter_idx, table->used_bitmap) ?
+ efx_filter_equal(spec, &table->spec[filter_idx]) :
+ for_insert) {
+ *depth_required = depth;
+ return filter_idx;
+ }
+
+ /* Return failure if we reached the maximum search depth */
+ if (depth == depth_max)
+ return for_insert ? -EBUSY : -ENOENT;
+
filter_idx = (filter_idx + incr) & (table->size - 1);
+ ++depth;
}
- if (!for_insert)
- return -ENOENT;
- if (depth > depth_max)
- return -EBUSY;
-found:
- *depth_required = depth;
- return filter_idx;
}
/* Construct/deconstruct external filter IDs */