On 3/21/19 6:30 AM, Johannes Thumshirn wrote:
> With the introduction of BIO_ALLOCED we've used up all available bits in
> bio::bi_flags.
>
> Make sure no-one adds a new one and thus overrides the BVEC_POOL_IDX
Two minor things:
> diff --git a/block/bio.c b/block/bio.c
> index 4db1008309ed..8c689aed46a0 100644
> --- a/block/bio.c
> +++ b/block/bio.c
> @@ -2126,12 +2126,20 @@ static void __init biovec_init_slabs(void)
> }
> }
>
> +static inline void bio_flag_buildtime_check(void)
> +{
> + BUILD_BUG_ON(BIO_FLAG_LAST > BVEC_POOL_OFFSET);
> +}
> +
> static int __init init_bio(void)
> {
> bio_slab_max = 2;
> bio_slab_nr = 0;
> bio_slabs = kcalloc(bio_slab_max, sizeof(struct bio_slab),
> GFP_KERNEL);
> +
> + bio_flag_buildtime_check();
> +
Just add the BUILD_BUG_ON() here, don't put it in a function.
> +enum {
> + BIO_SEG_VALID = 1, /* bi_phys_segments valid */
> + BIO_CLONED = 2, /* doesn't own data */
> + BIO_BOUNCED = 3, /* bio is a bounce bio */
> + BIO_USER_MAPPED = 4, /* contains user pages */
> + BIO_NULL_MAPPED = 5, /* contains invalid user pages */
> + BIO_QUIET = 6, /* Make BIO Quiet */
> + BIO_CHAIN = 7, /* chained bio, ->bi_remaining in
> effect */
> + BIO_REFFED = 8, /* bio has elevated ->bi_cnt */
> + BIO_THROTTLED = 9, /* This bio has already been subjected
> to
> + * throttling rules. Don't do it again.
> */
> + BIO_TRACE_COMPLETION = 10, /* bio_endio() should trace the final
> completion
> + * of this bio. */
> + BIO_QUEUE_ENTERED = 11, /* can use blk_queue_enter_live() */
> + BIO_TRACKED = 12, /* set if bio goes through the rq_qos
> path */
> + BIO_FLAG_LAST
> +};
Let's order this after the BIO_NO_PAGE_REF patch, so we can avoid
having to explicitly initialize the values.
You also haven't solved the issue of now having an extra bit, 2/2 uses
the last bit which the other patch already took...
--
Jens Axboe
