kernel/linux.git/lib/rhashtable.c, branch v4.18.17

lib/rhashtable: consider param->min_size when setting initial table size

2018-07-18T20:27:43+00:00

rhashtable_init() currently does not take into account the user-passed min_size parameter unless param->nelem_hint is set as well. As such, the default size (number of buckets) will always be HASH_DEFAULT_SIZE even if the smallest allowed size is larger than that. Remediate this by unconditionally calling into rounded_hashtable_size() and handling things accordingly. Signed-off-by: Davidlohr Bueso Acked-by: Herbert Xu Signed-off-by: David S. Miller

rhashtable: add restart routine in rhashtable_free_and_destroy()

2018-07-09T23:28:51+00:00

rhashtable_free_and_destroy() cancels re-hash deferred work then walks and destroys elements. at this moment, some elements can be still in future_tbl. that elements are not destroyed. test case: nft_rhash_destroy() calls rhashtable_free_and_destroy() to destroy all elements of sets before destroying sets and chains. But rhashtable_free_and_destroy() doesn't destroy elements of future_tbl. so that splat occurred. test script: %cat test.nft table ip aa { map map1 { type ipv4_addr : verdict; elements = { 0 : jump a0, 1 : jump a0, 2 : jump a0, 3 : jump a0, 4 : jump a0, 5 : jump a0, 6 : jump a0, 7 : jump a0, 8 : jump a0, 9 : jump a0, } } chain a0 { } } flush ruleset table ip aa { map map1 { type ipv4_addr : verdict; elements = { 0 : jump a0, 1 : jump a0, 2 : jump a0, 3 : jump a0, 4 : jump a0, 5 : jump a0, 6 : jump a0, 7 : jump a0, 8 : jump a0, 9 : jump a0, } } chain a0 { } } flush ruleset %while :; do nft -f test.nft; done Splat looks like: [ 200.795603] kernel BUG at net/netfilter/nf_tables_api.c:1363! [ 200.806944] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI [ 200.812253] CPU: 1 PID: 1582 Comm: nft Not tainted 4.17.0+ #24 [ 200.820297] Hardware name: To be filled by O.E.M. To be filled by O.E.M./Aptio CRB, BIOS 5.6.5 07/08/2015 [ 200.830309] RIP: 0010:nf_tables_chain_destroy.isra.34+0x62/0x240 [nf_tables] [ 200.838317] Code: 43 50 85 c0 74 26 48 8b 45 00 48 8b 4d 08 ba 54 05 00 00 48 c7 c6 60 6d 29 c0 48 c7 c7 c0 65 29 c0 4c 8b 40 08 e8 58 e5 fd f8 <0f> 0b 48 89 da 48 b8 00 00 00 00 00 fc ff [ 200.860366] RSP: 0000:ffff880118dbf4d0 EFLAGS: 00010282 [ 200.866354] RAX: 0000000000000061 RBX: ffff88010cdeaf08 RCX: 0000000000000000 [ 200.874355] RDX: 0000000000000061 RSI: 0000000000000008 RDI: ffffed00231b7e90 [ 200.882361] RBP: ffff880118dbf4e8 R08: ffffed002373bcfb R09: ffffed002373bcfa [ 200.890354] R10: 0000000000000000 R11: ffffed002373bcfb R12: dead000000000200 [ 200.898356] R13: dead000000000100 R14: ffffffffbb62af38 R15: dffffc0000000000 [ 200.906354] FS: 00007fefc31fd700(0000) GS:ffff88011b800000(0000) knlGS:0000000000000000 [ 200.915533] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 200.922355] CR2: 0000557f1c8e9128 CR3: 0000000106880000 CR4: 00000000001006e0 [ 200.930353] Call Trace: [ 200.932351] ? nf_tables_commit+0x26f6/0x2c60 [nf_tables] [ 200.939525] ? nf_tables_setelem_notify.constprop.49+0x1a0/0x1a0 [nf_tables] [ 200.947525] ? nf_tables_delchain+0x6e0/0x6e0 [nf_tables] [ 200.952383] ? nft_add_set_elem+0x1700/0x1700 [nf_tables] [ 200.959532] ? nla_parse+0xab/0x230 [ 200.963529] ? nfnetlink_rcv_batch+0xd06/0x10d0 [nfnetlink] [ 200.968384] ? nfnetlink_net_init+0x130/0x130 [nfnetlink] [ 200.975525] ? debug_show_all_locks+0x290/0x290 [ 200.980363] ? debug_show_all_locks+0x290/0x290 [ 200.986356] ? sched_clock_cpu+0x132/0x170 [ 200.990352] ? find_held_lock+0x39/0x1b0 [ 200.994355] ? sched_clock_local+0x10d/0x130 [ 200.999531] ? memset+0x1f/0x40 V2: - free all tables requested by Herbert Xu Signed-off-by: Taehee Yoo Acked-by: Herbert Xu Signed-off-by: David S. Miller

lib: rhashtable: Correct self-assignment in rhashtable.c

2018-07-03T14:25:37+00:00

In file lib/rhashtable.c line 777, skip variable is assigned to itself. The following error was observed: lib/rhashtable.c:777:41: warning: explicitly assigning value of variable of type 'int' to itself [-Wself-assign] error, forbidden warning: rhashtable.c:777 This error was found when compiling with Clang 6.0. Change it to iter->skip. Signed-off-by: Rishabh Bhatnagar Acked-by: Herbert Xu Reviewed-by: NeilBrown Signed-off-by: David S. Miller

rhashtable: improve rhashtable_walk stability when stop/start used.

2018-04-24T17:21:46+00:00

When a walk of an rhashtable is interrupted with rhastable_walk_stop() and then rhashtable_walk_start(), the location to restart from is based on a 'skip' count in the current hash chain, and this can be incorrect if insertions or deletions have happened. This does not happen when the walk is not stopped and started as iter->p is a placeholder which is safe to use while holding the RCU read lock. In rhashtable_walk_start() we can revalidate that 'p' is still in the same hash chain. If it isn't then the current method is still used. With this patch, if a rhashtable walker ensures that the current object remains in the table over a stop/start period (possibly by elevating the reference count if that is sufficient), it can be sure that a walk will not miss objects that were in the hashtable for the whole time of the walk. rhashtable_walk_start() may not find the object even though it is still in the hashtable if a rehash has moved it to a new table. In this case it will (eventually) get -EAGAIN and will need to proceed through the whole table again to be sure to see everything at least once. Acked-by: Herbert Xu Signed-off-by: NeilBrown Signed-off-by: David S. Miller

rhashtable: reset iter when rhashtable_walk_start sees new table

2018-04-24T17:21:45+00:00

The documentation claims that when rhashtable_walk_start_check() detects a resize event, it will rewind back to the beginning of the table. This is not true. We need to set ->slot and ->skip to be zero for it to be true. Acked-by: Herbert Xu Signed-off-by: NeilBrown Signed-off-by: David S. Miller

rhashtable: Revise incorrect comment on r{hl, hash}table_walk_enter()

2018-04-24T17:21:45+00:00

Neither rhashtable_walk_enter() or rhltable_walk_enter() sleep, though they do take a spinlock without irq protection. So revise the comments to accurately state the contexts in which these functions can be called. Acked-by: Herbert Xu Signed-off-by: NeilBrown Signed-off-by: David S. Miller

rhashtable: add schedule points

2018-04-01T03:25:39+00:00

Rehashing and destroying large hash table takes a lot of time, and happens in process context. It is safe to add cond_resched() in rhashtable_rehash_table() and rhashtable_free_and_destroy() Signed-off-by: Eric Dumazet Acked-by: Herbert Xu Signed-off-by: David S. Miller

rhashtable: Fix rhlist duplicates insertion

2018-03-07T15:44:02+00:00

When inserting duplicate objects (those with the same key), current rhlist implementation messes up the chain pointers by updating the bucket pointer instead of prev next pointer to the newly inserted node. This causes missing elements on removal and travesal. Fix that by properly updating pprev pointer to point to the correct rhash_head next pointer. Issue: 1241076 Change-Id: I86b2c140bcb4aeb10b70a72a267ff590bb2b17e7 Fixes: ca26893f05e8 ('rhashtable: Add rhlist interface') Signed-off-by: Paul Blakey Acked-by: Herbert Xu Signed-off-by: David S. Miller

rhashtable: Call library function alloc_bucket_locks

2017-12-11T14:58:39+00:00

To allocate the array of bucket locks for the hash table we now call library function alloc_bucket_spinlocks. This function is based on the old alloc_bucket_locks in rhashtable and should produce the same effect. Signed-off-by: Tom Herbert Signed-off-by: David S. Miller

rhashtable: Add rhastable_walk_peek

2017-12-11T14:58:38+00:00

This function is like rhashtable_walk_next except that it only returns the current element in the inter and does not advance the iter. This patch also creates __rhashtable_walk_find_next. It finds the next element in the table when the entry cached in iter is NULL or at the end of a slot. __rhashtable_walk_find_next is called from rhashtable_walk_next and rhastable_walk_peek. end_of_table is an added field to the iter structure. This indicates that the end of table was reached (walker.tbl being NULL is not a sufficient condition for end of table). Signed-off-by: Tom Herbert Acked-by: Herbert Xu Signed-off-by: David S. Miller