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Subject: Re: [PATCH] lightnvm: pblk: fix read_bitmap for 32bit archs
To:     igor.j.konopko@intel.com
Cc:     marcin.dziegielewski@intel.com, javier@cnexlabs.com,
        hans.holmberg@cnexlabs.com, hlitz@ucsc.edu,
        linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20180627194206.30384-1-mb@lightnvm.io>
 <c46fb234-a985-02e8-2122-c85e54f97b39@intel.com>
From:   =?UTF-8?Q?Matias_Bj=c3=b8rling?= <mb@lightnvm.io>
Message-ID: <259e585a-4d30-b270-1030-d3f9b0bf7e88@lightnvm.io>
Date:   Thu, 28 Jun 2018 10:10:16 +0200
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On 06/28/2018 12:18 AM, Igor Konopko wrote:
> 
> 
> On 27.06.2018 12:42, Matias Bjørling wrote:
>> If using pblk on a 32bit architecture, and there is a need to
>> perform a partial read, the partial read bitmap will only have
>> allocated 32 entries, where as 64 are needed.
>>
>> Make sure that the read_bitmap is initialized to 64bits on 32bit
>> architectures as well.
>>
>> Signed-off-by: Matias Bjørling <mb@lightnvm.io>
>> ---
>>   drivers/lightnvm/pblk-read.c | 14 +++++++-------
>>   1 file changed, 7 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/lightnvm/pblk-read.c b/drivers/lightnvm/pblk-read.c
>> index 6e93c489ce57..671635275d56 100644
>> --- a/drivers/lightnvm/pblk-read.c
>> +++ b/drivers/lightnvm/pblk-read.c
>> @@ -401,7 +401,7 @@ int pblk_submit_read(struct pblk *pblk, struct bio 
>> *bio)
>>       struct pblk_g_ctx *r_ctx;
>>       struct nvm_rq *rqd;
>>       unsigned int bio_init_idx;
>> -    unsigned long read_bitmap; /* Max 64 ppas per request */
>> +    DECLARE_BITMAP(read_bitmap, 64); /* Max 64 ppas per request */
> 
> Probably it would be nicer to use NVM_MAX_VLBA define instead of 
> explicit 64.
> 
>>       int ret = NVM_IO_ERR;
>>       /* logic error: lba out-of-bounds. Ignore read request */
>> @@ -413,7 +413,7 @@ int pblk_submit_read(struct pblk *pblk, struct bio 
>> *bio)
>>       generic_start_io_acct(q, READ, bio_sectors(bio), 
>> &pblk->disk->part0);
>> -    bitmap_zero(&read_bitmap, nr_secs);
>> +    bitmap_zero(read_bitmap, nr_secs);
>>       rqd = pblk_alloc_rqd(pblk, PBLK_READ);
>> @@ -444,19 +444,19 @@ int pblk_submit_read(struct pblk *pblk, struct 
>> bio *bio)
>>           rqd->ppa_list = rqd->meta_list + pblk_dma_meta_size;
>>           rqd->dma_ppa_list = rqd->dma_meta_list + pblk_dma_meta_size;
>> -        pblk_read_ppalist_rq(pblk, rqd, bio, blba, &read_bitmap);
>> +        pblk_read_ppalist_rq(pblk, rqd, bio, blba, read_bitmap 
>> >       } else {
>> -        pblk_read_rq(pblk, rqd, bio, blba, &read_bitmap);
>> +        pblk_read_rq(pblk, rqd, bio, blba, read_bitmap);
>>       }
>> -    if (bitmap_full(&read_bitmap, nr_secs)) {
>> +    if (bitmap_full(read_bitmap, nr_secs)) {
>>           atomic_inc(&pblk->inflight_io);
>>           __pblk_end_io_read(pblk, rqd, false);
>>           return NVM_IO_DONE;
>>       }
>>       /* All sectors are to be read from the device */
>> -    if (bitmap_empty(&read_bitmap, rqd->nr_ppas)) {
>> +    if (bitmap_empty(read_bitmap, rqd->nr_ppas)) {
>>           struct bio *int_bio = NULL;
>>           /* Clone read bio to deal with read errors internally */
>> @@ -480,7 +480,7 @@ int pblk_submit_read(struct pblk *pblk, struct bio 
>> *bio)
>>       /* The read bio request could be partially filled by the write 
>> buffer,
>>        * but there are some holes that need to be read from the drive.
>>        */
>> -    return pblk_partial_read(pblk, rqd, bio, bio_init_idx, 
>> &read_bitmap);
>> +    return pblk_partial_read(pblk, rqd, bio, bio_init_idx, read_bitmap);
>>   fail_rqd_free:
>>       pblk_free_rqd(pblk, rqd, PBLK_READ);
>>
> 
> Otherwise looks good.
> 
> Reviewed-by: Igor Konopko <igor.j.konopko@intel.com>

Thanks. I've applied it for 4.19 with the fix and also, now that 
NVM_MAX_VBLK is used, removed the max 64 ppas comment.