nvmet: limit passthru MTDS by BIO_MAX_PAGES (df06047d) · Commits · 戴 / test

nvmet_passthru_map_sg() only supports mapping a single BIO, not a chain so the effective maximum transfer should also be limitted by BIO_MAX_PAGES (presently this works out to 1MB). For PCI passthru devices the max_sectors would typically be more limitting than BIO_MAX_PAGES, but this may not be true for all passthru devices. Fixes: ("nvmet: add passthru code to process commands") Suggested-by:

Christoph Hellwig <hch@lst.de> Signed-off-by:

Logan Gunthorpe <logang@deltatee.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Sagi Grimberg <sagi@grimberg.me> Cc: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by:

Christoph Hellwig <hch@lst.de>

drivers/nvme/target/passthru.c

+8 −1

Original line number	Diff line number	Diff line
		@@ -26,7 +26,7 @@ static u16 nvmet_passthru_override_id_ctrl(struct nvmet_req *req)
		struct nvme_ctrl *pctrl = ctrl->subsys->passthru_ctrl;
		u16 status = NVME_SC_SUCCESS;
		struct nvme_id_ctrl *id;
		u32 max_hw_sectors;
		int max_hw_sectors;
		int page_shift;

		id = kzalloc(sizeof(*id), GFP_KERNEL);
		@@ -48,6 +48,13 @@ static u16 nvmet_passthru_override_id_ctrl(struct nvmet_req *req)
		max_hw_sectors = min_not_zero(pctrl->max_segments << (PAGE_SHIFT - 9),
		pctrl->max_hw_sectors);

		/*
		* nvmet_passthru_map_sg is limitted to using a single bio so limit
		* the mdts based on BIO_MAX_PAGES as well
		*/
		max_hw_sectors = min_not_zero(BIO_MAX_PAGES << (PAGE_SHIFT - 9),
		max_hw_sectors);

		page_shift = NVME_CAP_MPSMIN(ctrl->cap) + 12;

		id->mdts = ilog2(max_hw_sectors) + 9 - page_shift;

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