Messages in this thread | | | Subject | Re: [PATCH] lightnvm: pblk: adjust the position of the lock | From | Matias Bjørling <> | Date | Tue, 27 Nov 2018 15:26:15 +0100 |
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On 11/27/2018 03:24 PM, Javier Gonzalez wrote: > >> On 27 Nov 2018, at 15.22, Matias Bjørling <mb@lightnvm.io> wrote: >> >> On 11/27/2018 01:57 PM, Javier Gonzalez wrote: >>>> On 27 Nov 2018, at 02.53, Hua Su <suhua.tanke@gmail.com> wrote: >>>> >>>> Add lock protection for list operations. >>>> Signed-off-by: Hua Su <suhua.tanke@gmail.com> >>>> --- >>>> drivers/lightnvm/pblk-core.c | 17 ++++++++++------- >>>> 1 file changed, 10 insertions(+), 7 deletions(-) >>>> >>>> diff --git a/drivers/lightnvm/pblk-core.c b/drivers/lightnvm/pblk-core.c >>>> index 6944aac43b01..e490df217dac 100644 >>>> --- a/drivers/lightnvm/pblk-core.c >>>> +++ b/drivers/lightnvm/pblk-core.c >>>> @@ -1286,24 +1286,27 @@ int pblk_line_recov_alloc(struct pblk *pblk, struct pblk_line *line) >>>> list_del(&line->list); >>>> >>>> ret = pblk_line_prepare(pblk, line); >>>> - if (ret) { >>>> - list_add(&line->list, &l_mg->free_list); >>>> - spin_unlock(&l_mg->free_lock); >>>> - return ret; >>>> - } >>>> - spin_unlock(&l_mg->free_lock); >>>> + if (ret) >>>> + goto out; >>>> >>>> ret = pblk_line_alloc_bitmaps(pblk, line); >>>> if (ret) >>>> - return ret; >>>> + goto out; >>>> >>>> if (!pblk_line_init_bb(pblk, line, 0)) { >>>> list_add(&line->list, &l_mg->free_list); >>>> + spin_unlock(&l_mg->free_lock); >>>> return -EINTR; >>>> } >>>> + spin_unlock(&l_mg->free_lock); >>>> >>>> pblk_rl_free_lines_dec(&pblk->rl, line, true); >>>> return 0; >>>> + >>>> +out: >>>> + list_add(&line->list, &l_mg->free_list); >>>> + spin_unlock(&l_mg->free_lock); >>>> + return ret; >>>> } >>>> >>>> void pblk_line_recov_close(struct pblk *pblk, struct pblk_line *line) >>>> -- >>>> 2.19.1 >>> This path is only touched by the recovery path, which is single >>> threaded, so there is no race condition as is. Also, if recovery fails, >>> pblk will not create the instance at all. This said, it would be >>> good to protect the list_add on the pblk_line_init_bb() error path in >>> case this code is used for some other purpose in the future. >> >> I like your explanation here. Another option is that we could add a comment to notify the developer that it safe in this context? > > Sure. Do you want to add it? Or should I send it? > > Javier >
Please send it. Thanks!
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