From: Logan Gunthorpe <logang@deltatee.com>
Date: Fri, 16 Oct 2020 22:19:04 +0000 (-0600)
Subject: nvmet: limit passthru MTDS by BIO_MAX_PAGES
X-Git-Tag: howlett/maple_spf/20210104~701^2~1^2~6
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=df06047d54276f73782c9d97882b305fca745d3f;p=users%2Fjedix%2Flinux-maple.git
nvmet: limit passthru MTDS by BIO_MAX_PAGES
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: c1fef73f793b ("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>
---
diff --git a/drivers/nvme/target/passthru.c b/drivers/nvme/target/passthru.c
index 56c571052216..323046e1d67f 100644
--- a/drivers/nvme/target/passthru.c
+++ b/drivers/nvme/target/passthru.c
@@ -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;