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block: Allow mapping of vmalloc-ed buffers 

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: 515ce60613 ("scsi: sd_zbc: Fix sd_zbc_report_zones() buffer allocation")
Fixes: e76239a374 ("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>
alistair/sunxi64-5.4-dsi
Damien Le Moal 2019-07-01 14:09:15 +09:00 committed by Jens Axboe
parent e7bf90e5af
commit b4c5875d36
1 changed files with 27 additions and 1 deletions
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28
block/bio.c
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@ -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"
@ -1441,8 +1442,22 @@ 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);
}
@ -1463,6 +1478,8 @@ struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
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;
@ -1470,6 +1487,11 @@ struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
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;
@ -1480,7 +1502,11 @@ struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
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);