[PATCH net-next-2.6 1/7] sfc: Fix loop condition for efx_filter_search() when !for_insert
From: Ben Hutchings <hidden>
Date: 2011-07-14 01:16:42
Subsystem:
networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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 <redacted>
---
drivers/net/sfc/filter.c | 41 ++++++++++++++++++++++++-----------------
1 files changed, 24 insertions(+), 17 deletions(-)
diff --git a/drivers/net/sfc/filter.c b/drivers/net/sfc/filter.c
index f2fc258..054f0a3 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 */
--
1.7.4.4
--
Ben Hutchings, Senior Software Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.