kernel/linux.git/lib/test_rhashtable.c, branch v6.1.168

rhashtable: make test actually random

2022-10-26T12:39:09+00:00

The "random rhlist add/delete operations" actually wasn't very random, as all cases tested the same bit. Since the later parts of this loop depend on the first case execute this unconditionally, and then test on different bits for the remaining tests. While at it only request as much random bits as are actually used. Signed-off-by: Rolf Eike Beer Acked-by: Herbert Xu Signed-off-by: David S. Miller

treewide: use get_random_u32() when possible

2022-10-11T23:42:58+00:00

The prandom_u32() function has been a deprecated inline wrapper around get_random_u32() for several releases now, and compiles down to the exact same code. Replace the deprecated wrapper with a direct call to the real function. The same also applies to get_random_int(), which is just a wrapper around get_random_u32(). This was done as a basic find and replace. Reviewed-by: Greg Kroah-Hartman Reviewed-by: Kees Cook Reviewed-by: Yury Norov Reviewed-by: Jan Kara # for ext4 Acked-by: Toke Høiland-Jørgensen # for sch_cake Acked-by: Chuck Lever # for nfsd Acked-by: Jakub Kicinski Acked-by: Mika Westerberg # for thunderbolt Acked-by: Darrick J. Wong # for xfs Acked-by: Helge Deller # for parisc Acked-by: Heiko Carstens # for s390 Signed-off-by: Jason A. Donenfeld

rhashtable: avoid -Wrestrict warning on overlapping sprintf output

2021-03-24T22:16:09+00:00

sprintf() is declared with a restrict keyword to not allow input and output to point to the same buffer: lib/test_rhashtable.c: In function 'print_ht': lib/test_rhashtable.c:504:4: error: 'sprintf' argument 3 overlaps destination object 'buff' [-Werror=restrict] 504 | sprintf(buff, "%s\nbucket[%d] -> ", buff, i); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ lib/test_rhashtable.c:489:7: note: destination object referenced by 'restrict'-qualified argument 1 was declared here 489 | char buff[512] = ""; | ^~~~ Rework this function to remember the last offset instead to avoid the warning. Signed-off-by: Arnd Bergmann Signed-off-by: David S. Miller

rhashtable: fix indentation of a continue statement

2020-09-20T21:10:06+00:00

A continue statement is indented incorrectly, add in the missing tab. Signed-off-by: Colin Ian King Acked-by: Herbert Xu Signed-off-by: David S. Miller

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55+00:00

Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Enrico Weigelt Reviewed-by: Kate Stewart Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman

rhashtable: move dereference inside rht_ptr()

2019-04-13T00:34:45+00:00

Rather than dereferencing a pointer to a bucket and then passing the result to rht_ptr(), we now pass in the pointer and do the dereference in rht_ptr(). This requires that we pass in the tbl and hash as well to support RCU checks, and means that the various rht_for_each functions can expect a pointer that can be dereferenced without further care. There are two places where we dereference a bucket pointer where there is no testable protection - in each case we know that we much have exclusive access without having taken a lock. The previous code used rht_dereference() to pretend that holding the mutex provided protects, but holding the mutex never provides protection for accessing buckets. So instead introduce rht_ptr_exclusive() that can be used when there is known to be exclusive access without holding any locks. Signed-off-by: NeilBrown Signed-off-by: David S. Miller

rhashtable: use bit_spin_locks to protect hash bucket.

2019-04-08T02:12:12+00:00

This patch changes rhashtables to use a bit_spin_lock on BIT(1) of the bucket pointer to lock the hash chain for that bucket. The benefits of a bit spin_lock are: - no need to allocate a separate array of locks. - no need to have a configuration option to guide the choice of the size of this array - locking cost is often a single test-and-set in a cache line that will have to be loaded anyway. When inserting at, or removing from, the head of the chain, the unlock is free - writing the new address in the bucket head implicitly clears the lock bit. For __rhashtable_insert_fast() we ensure this always happens when adding a new key. - even when lockings costs 2 updates (lock and unlock), they are in a cacheline that needs to be read anyway. The cost of using a bit spin_lock is a little bit of code complexity, which I think is quite manageable. Bit spin_locks are sometimes inappropriate because they are not fair - if multiple CPUs repeatedly contend of the same lock, one CPU can easily be starved. This is not a credible situation with rhashtable. Multiple CPUs may want to repeatedly add or remove objects, but they will typically do so at different buckets, so they will attempt to acquire different locks. As we have more bit-locks than we previously had spinlocks (by at least a factor of two) we can expect slightly less contention to go with the slightly better cache behavior and reduced memory consumption. To enhance type checking, a new struct is introduced to represent the pointer plus lock-bit that is stored in the bucket-table. This is "struct rhash_lock_head" and is empty. A pointer to this needs to be cast to either an unsigned lock, or a "struct rhash_head *" to be useful. Variables of this type are most often called "bkt". Previously "pprev" would sometimes point to a bucket, and sometimes a ->next pointer in an rhash_head. As these are now different types, pprev is NULL when it would have pointed to the bucket. In that case, 'blk' is used, together with correct locking protocol. Signed-off-by: NeilBrown Signed-off-by: David S. Miller

rhashtable: Remove obsolete rhashtable_walk_init function

2019-02-22T12:49:00+00:00

The rhashtable_walk_init function has been obsolete for more than two years. This patch finally converts its last users over to rhashtable_walk_enter and removes it. Signed-off-by: Herbert Xu Signed-off-by: Johannes Berg

lib/test_rhashtable: fix spelling mistake "existant" -> "existent"

2019-02-21T21:09:11+00:00

There are spelling mistakes in warning macro messages. Fix them. Signed-off-by: Colin Ian King Acked-by: Herbert Xu Signed-off-by: David S. Miller

lib/test_rhashtable: Make test_insert_dup() allocate its hash table dynamically

2019-01-31T17:36:52+00:00

The test_insert_dup() function from lib/test_rhashtable.c passes a pointer to a stack object to rhltable_init(). Allocate the hash table dynamically to avoid that the following is reported with object debugging enabled: ODEBUG: object (ptrval) is on stack (ptrval), but NOT annotated. WARNING: CPU: 0 PID: 1 at lib/debugobjects.c:368 __debug_object_init+0x312/0x480 Modules linked in: EIP: __debug_object_init+0x312/0x480 Call Trace: ? debug_object_init+0x1a/0x20 ? __init_work+0x16/0x30 ? rhashtable_init+0x1e1/0x460 ? sched_clock_cpu+0x57/0xe0 ? rhltable_init+0xb/0x20 ? test_insert_dup+0x32/0x20f ? trace_hardirqs_on+0x38/0xf0 ? ida_dump+0x10/0x10 ? jhash+0x130/0x130 ? my_hashfn+0x30/0x30 ? test_rht_init+0x6aa/0xab4 ? ida_dump+0x10/0x10 ? test_rhltable+0xc5c/0xc5c ? do_one_initcall+0x67/0x28e ? trace_hardirqs_off+0x22/0xe0 ? restore_all_kernel+0xf/0x70 ? trace_hardirqs_on_thunk+0xc/0x10 ? restore_all_kernel+0xf/0x70 ? kernel_init_freeable+0x142/0x213 ? rest_init+0x230/0x230 ? kernel_init+0x10/0x110 ? schedule_tail_wrapper+0x9/0xc ? ret_from_fork+0x19/0x24 Cc: Thomas Graf Cc: Herbert Xu Cc: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Bart Van Assche Acked-by: Herbert Xu Signed-off-by: David S. Miller