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>
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block/bio.c
28
block/bio.c
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@ -16,6 +16,7 @@
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#include <linux/workqueue.h>
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#include <linux/cgroup.h>
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#include <linux/blk-cgroup.h>
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#include <linux/highmem.h>
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#include <trace/events/block.h>
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#include "blk.h"
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@ -1441,8 +1442,22 @@ void bio_unmap_user(struct bio *bio)
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bio_put(bio);
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}
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static void bio_invalidate_vmalloc_pages(struct bio *bio)
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{
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#ifdef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
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if (bio->bi_private && !op_is_write(bio_op(bio))) {
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unsigned long i, len = 0;
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for (i = 0; i < bio->bi_vcnt; i++)
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len += bio->bi_io_vec[i].bv_len;
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invalidate_kernel_vmap_range(bio->bi_private, len);
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}
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#endif
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}
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static void bio_map_kern_endio(struct bio *bio)
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{
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bio_invalidate_vmalloc_pages(bio);
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bio_put(bio);
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}
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@ -1463,6 +1478,8 @@ struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
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unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
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unsigned long start = kaddr >> PAGE_SHIFT;
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const int nr_pages = end - start;
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bool is_vmalloc = is_vmalloc_addr(data);
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struct page *page;
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int offset, i;
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struct bio *bio;
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@ -1470,6 +1487,11 @@ struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
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if (!bio)
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return ERR_PTR(-ENOMEM);
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if (is_vmalloc) {
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flush_kernel_vmap_range(data, len);
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bio->bi_private = data;
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}
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offset = offset_in_page(kaddr);
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for (i = 0; i < nr_pages; i++) {
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unsigned int bytes = PAGE_SIZE - offset;
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@ -1480,7 +1502,11 @@ struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
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if (bytes > len)
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bytes = len;
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if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
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if (!is_vmalloc)
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page = virt_to_page(data);
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else
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page = vmalloc_to_page(data);
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if (bio_add_pc_page(q, bio, page, bytes,
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offset) < bytes) {
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/* we don't support partial mappings */
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bio_put(bio);
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