wireguard-linux/drivers/md/bcache/bset.c, branch jd/unified-crypt-queue

bcache: add code comments for state->pool in __btree_sort()

2020-01-23T18:40:02Z

To explain the pages allocated from mempool state->pool can be swapped in __btree_sort(), because state->pool is a page pool, which allocates pages by alloc_pages() indeed. Signed-off-by: Coly Li Signed-off-by: Jens Axboe

bcache: don't export symbols

2019-11-13T22:42:51Z

None of the exported bcache symbols are actually used anywhere. Signed-off-by: Christoph Hellwig Signed-off-by: Coly Li Signed-off-by: Jens Axboe

bcache: add code comment bch_keylist_pop() and bch_keylist_pop_front()

2019-11-13T22:42:50Z

This patch adds simple code comments for bch_keylist_pop() and bch_keylist_pop_front() in bset.c, to make the code more easier to be understand. Signed-off-by: Coly Li Signed-off-by: Jens Axboe

bcache: make bset_search_tree() be more understandable

2019-06-28T13:39:15Z

The purpose of following code in bset_search_tree() is to avoid a branch instruction, 994 if (likely(f->exponent != 127)) 995 n = j * 2 + (((unsigned int) 996 (f->mantissa - 997 bfloat_mantissa(search, f))) >> 31); 998 else 999 n = (bkey_cmp(tree_to_bkey(t, j), search) > 0) 1000 ? j * 2 1001 : j * 2 + 1; This piece of code is not very clear to understand, even when I tried to add code comment for it, I made mistake. This patch removes the implict bit operation and uses explicit branch to calculate next location in binary tree search. Signed-off-by: Coly Li Signed-off-by: Jens Axboe

bcache: remove unncessary code in bch_btree_keys_init()

2019-06-28T13:39:15Z

Function bch_btree_keys_init() initializes b->set[].size and b->set[].data to zero. As the code comments indicates, these code indeed is unncessary, because both struct btree_keys and struct bset_tree are nested embedded into struct btree, when struct btree is filled with 0 bits by kzalloc() in mca_bucket_alloc(), b->set[].size and b->set[].data are initialized to 0 (a.k.a NULL) already. This patch removes the redundant code, and add comments in bch_btree_keys_init() and mca_bucket_alloc() to explain why it's safe. Signed-off-by: Coly Li Signed-off-by: Jens Axboe

bcache: remove unnecessary prefetch() in bset_search_tree()

2019-06-28T13:39:14Z

In function bset_search_tree(), when p >= t->size, t->tree[0] will be prefetched by the following code piece, 974 unsigned int p = n << 4; 975 976 p &= ((int) (p - t->size)) >> 31; 977 978 prefetch(&t->tree[p]); The purpose of the above code is to avoid a branch instruction, but when p >= t->size, prefetch(&t->tree[0]) has no positive performance contribution at all. This patch avoids the unncessary prefetch by only calling prefetch() when p < t->size. Signed-off-by: Coly Li Signed-off-by: Jens Axboe

bcache: fix stack corruption by PRECEDING_KEY()

2019-06-13T09:09:14Z

Recently people report bcache code compiled with gcc9 is broken, one of the buggy behavior I observe is that two adjacent 4KB I/Os should merge into one but they don't. Finally it turns out to be a stack corruption caused by macro PRECEDING_KEY(). See how PRECEDING_KEY() is defined in bset.h, 437 #define PRECEDING_KEY(_k) \ 438 ({ \ 439 struct bkey *_ret = NULL; \ 440 \ 441 if (KEY_INODE(_k) || KEY_OFFSET(_k)) { \ 442 _ret = &KEY(KEY_INODE(_k), KEY_OFFSET(_k), 0); \ 443 \ 444 if (!_ret->low) \ 445 _ret->high--; \ 446 _ret->low--; \ 447 } \ 448 \ 449 _ret; \ 450 }) At line 442, _ret points to address of a on-stack variable combined by KEY(), the life range of this on-stack variable is in line 442-446, once _ret is returned to bch_btree_insert_key(), the returned address points to an invalid stack address and this address is overwritten in the following called bch_btree_iter_init(). Then argument 'search' of bch_btree_iter_init() points to some address inside stackframe of bch_btree_iter_init(), exact address depends on how the compiler allocates stack space. Now the stack is corrupted. Fixes: 0eacac22034c ("bcache: PRECEDING_KEY()") Signed-off-by: Coly Li Reviewed-by: Rolf Fokkens Reviewed-by: Pierre JUHEN Tested-by: Shenghui Wang Tested-by: Pierre JUHEN Cc: Kent Overstreet Cc: Nix Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe

bcache: fix code comments style

2018-08-11T21:46:42Z

This patch fixes 3 style issues warned by checkpatch.pl, - Comment lines are not aligned - Comments use "/*" on subsequent lines - Comment lines use a trailing "*/" Signed-off-by: Coly Li Reviewed-by: Shenghui Wang Signed-off-by: Jens Axboe

bcache: replace printk() by pr_*() routines

2018-08-11T21:46:41Z

There are still many places in bcache use printk to display kernel message, which are suggested to be preplaced by pr_*() routines like pr_err(), pr_info(), or pr_notice(). This patch replaces all printk() with a proper pr_*() routine for bcache code. Signed-off-by: Coly Li Reviewed-by: Shenghui Wang Signed-off-by: Jens Axboe

bcache: style fixes for lines over 80 characters

2018-08-11T21:46:41Z

This patch fixes the lines over 80 characters into more lines, to minimize warnings by checkpatch.pl. There are still some lines exceed 80 characters, but it is better to be a single line and I don't change them. Signed-off-by: Coly Li Reviewed-by: Shenghui Wang Signed-off-by: Jens Axboe