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Commit b4c5875d authored by Damien Le Moal's avatar Damien Le Moal Committed by Jens Axboe
Browse files

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: 515ce606 ("scsi: sd_zbc: Fix sd_zbc_report_zones() buffer allocation")
Fixes: e76239a3 ("block: add a report_zones method")
Cc: stable@vger.kernel.org
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: default avatarDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent e7bf90e5

block/bio.c

+27 −1
Original line number Diff line number Diff line
@@ -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);