On Thu, Jun 27, 2019 at 06:29:42PM +0900, Damien Le Moal wrote:
> To allow the SCSI subsystem scsi_execute_req() function to issue
> requests using large buffers that are better allocated with vmalloc()
> rather than kmalloc(), modify bio_map_kern() to allow passing a buffer
> allocated with vmalloc().
>
> To do so, detect vmalloc-ed buffers using is_vmalloc_addr(). For
> vmalloc-ed buffers, flush the buffer using flush_kernel_vmap_range(),
> use vmalloc_to_page() instead of virt_to_page() to obtain the pages of
> the buffer, and invalidate the buffer addresses with
> invalidate_kernel_vmap_range() on completion of read BIOs. This last
> point is executed using the function bio_invalidate_vmalloc_pages()
> which is defined only if the architecture defines
> ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE, that is, if the architecture
> actually needs the invalidation done.
>
> Fixes: 515ce6061312 ("scsi: sd_zbc: Fix sd_zbc_report_zones() buffer allocation")
> Fixes: e76239a3748c ("block: add a report_zones method")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxx>
> ---
> block/bio.c | 29 ++++++++++++++++++++++++++++-
> 1 file changed, 28 insertions(+), 1 deletion(-)
>
> diff --git a/block/bio.c b/block/bio.c
> index ce797d73bb43..bbba5f08b2ef 100644
> --- a/block/bio.c
> +++ b/block/bio.c
> @@ -16,6 +16,7 @@
> #include <linux/workqueue.h>
> #include <linux/cgroup.h>
> #include <linux/blk-cgroup.h>
> +#include <linux/highmem.h>
>
> #include <trace/events/block.h>
> #include "blk.h"
> @@ -1479,8 +1480,22 @@ void bio_unmap_user(struct bio *bio)
> bio_put(bio);
> }
>
> +static void bio_invalidate_vmalloc_pages(struct bio *bio)
> +{
> +#ifdef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
> + if (bio->bi_private && !op_is_write(bio_op(bio))) {
> + unsigned long i, len = 0;
> +
> + for (i = 0; i < bio->bi_vcnt; i++)
> + len += bio->bi_io_vec[i].bv_len;
> + invalidate_kernel_vmap_range(bio->bi_private, len);
> + }
> +#endif
> +}
Normal Linux style is to keep the ifdefs outside the functions,
or use IS_ENABLED, although the latter would require
ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE to be a config option. Not that
I personally care much.
> @@ -1531,6 +1557,7 @@ struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
> }
>
> bio->bi_end_io = bio_map_kern_endio;
> +
> return bio;
> }
Superflous whitespace change.
Otherwise look good:
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
