block: Allow bio_iov_iter_get_pages() with bio->bi_bdev unset
bio_iov_iter_get_pages() trims the IO based on the block size of the block device the IO will be issued to. However, bcachefs is a multi device filesystem; when we're creating the bio we don't yet know which block device the bio will be submitted to - we have to handle the alignment checks elsewhere. Thus this is needed to avoid a null ptr deref. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev> Cc: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org Link: https://lore.kernel.org/r/20230813182636.2966159-3-kent.overstreet@linux.dev Signed-off-by: Jens Axboe <axboe@kernel.dk>
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parent
7ba3792718
commit
168145f617
10
block/bio.c
10
block/bio.c
@ -1231,7 +1231,7 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
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struct page **pages = (struct page **)bv;
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ssize_t size, left;
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unsigned len, i = 0;
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size_t offset, trim;
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size_t offset;
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int ret = 0;
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/*
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@ -1260,10 +1260,12 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
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nr_pages = DIV_ROUND_UP(offset + size, PAGE_SIZE);
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trim = size & (bdev_logical_block_size(bio->bi_bdev) - 1);
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iov_iter_revert(iter, trim);
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if (bio->bi_bdev) {
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size_t trim = size & (bdev_logical_block_size(bio->bi_bdev) - 1);
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iov_iter_revert(iter, trim);
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size -= trim;
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}
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size -= trim;
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if (unlikely(!size)) {
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ret = -EFAULT;
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goto out;
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