From: Damien Le Moal damien.lemoal@wdc.com
commit b4c5875d36178e8df409bdce232f270cac89fafe upstream.
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@vger.kernel.org Reviewed-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Damien Le Moal damien.lemoal@wdc.com Reviewed-by: Christoph Hellwig hch@lst.de Reviewed-by: Chaitanya Kulkarni chaitanya.kulkarni@wdc.com Reviewed-by: Ming Lei ming.lei@redhat.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- block/bio.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-)
--- a/block/bio.c +++ b/block/bio.c @@ -29,6 +29,7 @@ #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" @@ -1475,8 +1476,22 @@ 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 +} + static void bio_map_kern_endio(struct bio *bio) { + bio_invalidate_vmalloc_pages(bio); bio_put(bio); }
@@ -1497,6 +1512,8 @@ struct bio *bio_map_kern(struct request_ unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; unsigned long start = kaddr >> PAGE_SHIFT; const int nr_pages = end - start; + bool is_vmalloc = is_vmalloc_addr(data); + struct page *page; int offset, i; struct bio *bio;
@@ -1504,6 +1521,11 @@ struct bio *bio_map_kern(struct request_ if (!bio) return ERR_PTR(-ENOMEM);
+ if (is_vmalloc) { + flush_kernel_vmap_range(data, len); + bio->bi_private = data; + } + offset = offset_in_page(kaddr); for (i = 0; i < nr_pages; i++) { unsigned int bytes = PAGE_SIZE - offset; @@ -1514,7 +1536,11 @@ struct bio *bio_map_kern(struct request_ if (bytes > len) bytes = len;
- if (bio_add_pc_page(q, bio, virt_to_page(data), bytes, + if (!is_vmalloc) + page = virt_to_page(data); + else + page = vmalloc_to_page(data); + if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes) { /* we don't support partial mappings */ bio_put(bio);