[PATCH v3 1/1] nvme : Add ioctl to query nvme attributes
Joel Granados
j.granados at samsung.com
Thu Nov 17 06:13:37 PST 2022
An ioctl (NVME_IOCTL_GET_ATTR) is added to query nvme controller
attributes needed to effectively write to the char device without needing
to be a privileged user. They are also provided on block devices for
convenience. The attributes here are meant to complement what you can
already get with the allowed identify commands.
New members are added to the nvme_ctrl struct: dmsl, vsl and wusl from
the I/O Command Set Specific Identify Controller Data Structure in the nvme
spec.
We add NVME_IOCTL_GET_ATTR_{V0SZ,CURZS} in order to make the ioctl
extensible. These serve as both size and version. The caller is expected to
pass the structure size as the first member of the struct. For example:
{...
struct nvme_get_attr nvme_get_attr = {0};
nvme_get_attr.argsz = sizeof(struct nvme_get_attr);
...}
Signed-off-by: Joel Granados <j.granados at samsung.com>
---
drivers/nvme/host/core.c | 8 ++++-
drivers/nvme/host/ioctl.c | 61 +++++++++++++++++++++++++++++++++
drivers/nvme/host/nvme.h | 11 ++++++
include/uapi/linux/nvme_ioctl.h | 23 +++++++++++++
4 files changed, 102 insertions(+), 1 deletion(-)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index f94b05c585cb..51c99302786b 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -3061,9 +3061,12 @@ static int nvme_init_non_mdts_limits(struct nvme_ctrl *ctrl)
if (id->dmrl)
ctrl->max_discard_segments = id->dmrl;
- ctrl->dmrsl = le32_to_cpu(id->dmrsl);
if (id->wzsl)
ctrl->max_zeroes_sectors = nvme_mps_to_sectors(ctrl, id->wzsl);
+ ctrl->dmrsl = le32_to_cpu(id->dmrsl);
+ ctrl->dmsl = le64_to_cpu(id->dmsl);
+ ctrl->vsl = id->vsl;
+ ctrl->wusl = id->wusl;
free_data:
kfree(id);
@@ -5246,6 +5249,9 @@ static inline void _nvme_check_size(void)
BUILD_BUG_ON(sizeof(struct nvme_dbbuf) != 64);
BUILD_BUG_ON(sizeof(struct nvme_directive_cmd) != 64);
BUILD_BUG_ON(sizeof(struct nvme_feat_host_behavior) != 512);
+ BUILD_BUG_ON(sizeof(struct nvme_get_attr) < NVME_IOCTL_GET_ATTR_V0SZ);
+ BUILD_BUG_ON(sizeof(struct nvme_get_attr) != NVME_IOCTL_GET_ATTR_CURSZ);
+
}
diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
index 9273db147872..daafea38d39b 100644
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -53,6 +53,61 @@ static void __user *nvme_to_user_ptr(uintptr_t ptrval)
return (void __user *)ptrval;
}
+/*
+ * Reverse conversion from sectors to original NVMe values expressed in units
+ * of MPSMIN. Use ilog2 to change to power of 2 values and then reverse what
+ * was done in nvme_mps_to_sectors. 9 is the kernel sectors size and 12 is part
+ * of how mpsmin is defined in the NVMe spec (2^(12 + mpsmin))
+ */
+static inline u32 nvme_sectors_to_mps(struct nvme_ctrl *ctrl, u32 unit)
+{
+ return ilog2(unit) + 9 - 12 - NVME_CAP_MPSMIN(ctrl->cap);
+}
+
+static int nvme_ctrl_export_attrs(struct nvme_ctrl *ctrl,
+ struct nvme_get_attr __user *arg)
+{
+ struct nvme_get_attr nvme_get_attr = { };
+ __u32 usize, retsize;
+ int ret;
+
+ if (copy_from_user(&nvme_get_attr, arg, 2 * sizeof(__u32)))
+ return -EFAULT;
+
+ if (nvme_get_attr.flags != 0)
+ return -EINVAL;
+
+ if (nvme_get_attr.argsz < NVME_IOCTL_GET_ATTR_V0SZ)
+ return -EINVAL;
+ usize = nvme_get_attr.argsz;
+
+ /* Enforce backwards compatibility */
+ ret = copy_struct_from_user(&nvme_get_attr, NVME_IOCTL_GET_ATTR_CURSZ,
+ arg, usize);
+ if (ret)
+ return ret;
+
+ nvme_get_attr.argsz = NVME_IOCTL_GET_ATTR_CURSZ;
+ nvme_get_attr.mpsmin = NVME_CAP_MPSMIN(ctrl->cap);
+ nvme_get_attr.vsl = ctrl->vsl;
+ nvme_get_attr.wusl = ctrl->wusl;
+ nvme_get_attr.dmrl = ctrl->max_discard_segments;
+ nvme_get_attr.dmsl = ctrl->dmsl;
+ nvme_get_attr.dmrsl = ctrl->dmrsl;
+ nvme_get_attr.oncs = ctrl->oncs;
+ if (ctrl->max_zeroes_sectors > 0)
+ nvme_get_attr.wzsl = nvme_sectors_to_mps(ctrl, ctrl->max_zeroes_sectors);
+ if (ctrl->max_hw_sectors > 0)
+ nvme_get_attr.mdts = nvme_sectors_to_mps(ctrl, ctrl->max_hw_sectors);
+
+ retsize = min(usize, NVME_IOCTL_GET_ATTR_CURSZ);
+ ret = copy_to_user((struct nvme_get_attr __user *)arg, &nvme_get_attr, retsize);
+ if (ret)
+ return -EFAULT;
+
+ return 0;
+}
+
static void *nvme_add_user_metadata(struct request *req, void __user *ubuf,
unsigned len, u32 seed)
{
@@ -613,6 +668,8 @@ static int nvme_ctrl_ioctl(struct nvme_ctrl *ctrl, unsigned int cmd,
return nvme_user_cmd(ctrl, NULL, argp, mode);
case NVME_IOCTL_ADMIN64_CMD:
return nvme_user_cmd64(ctrl, NULL, argp, false, mode);
+ case NVME_IOCTL_GET_ATTR:
+ return nvme_ctrl_export_attrs(ctrl, argp);
default:
return sed_ioctl(ctrl->opal_dev, cmd, argp);
}
@@ -659,6 +716,8 @@ static int nvme_ns_ioctl(struct nvme_ns *ns, unsigned int cmd,
return nvme_user_cmd64(ns->ctrl, ns, argp, false, mode);
case NVME_IOCTL_IO64_CMD_VEC:
return nvme_user_cmd64(ns->ctrl, ns, argp, true, mode);
+ case NVME_IOCTL_GET_ATTR:
+ return nvme_ctrl_export_attrs(ns->ctrl, argp);
default:
return -ENOTTY;
}
@@ -950,6 +1009,8 @@ long nvme_dev_ioctl(struct file *file, unsigned int cmd,
return -EACCES;
nvme_queue_scan(ctrl);
return 0;
+ case NVME_IOCTL_GET_ATTR:
+ return nvme_ctrl_export_attrs(ctrl, argp);
default:
return -ENOTTY;
}
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index f9df10653f3c..0f36259a7992 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -292,6 +292,9 @@ struct nvme_ctrl {
u16 crdt[3];
u16 oncs;
u32 dmrsl;
+ u64 dmsl;
+ u8 vsl;
+ u8 wusl;
u16 oacs;
u16 sqsize;
u32 max_namespaces;
@@ -814,6 +817,7 @@ int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
union nvme_result *result, void *buffer, unsigned bufflen,
int qid, int at_head,
blk_mq_req_flags_t flags);
+
int nvme_set_features(struct nvme_ctrl *dev, unsigned int fid,
unsigned int dword11, void *buffer, size_t buflen,
u32 *result);
@@ -1071,4 +1075,11 @@ static inline const unsigned char *nvme_get_admin_opcode_str(u8 opcode)
}
#endif /* CONFIG_NVME_VERBOSE_ERRORS */
+/*
+ * List of all nvme ioctl controller attribute calls. Use size of nvme_get_attr
+ * as the version which enables us to use copy_struct_from_user
+ */
+#define NVME_IOCTL_GET_ATTR_V0SZ 32u
+#define NVME_IOCTL_GET_ATTR_CURSZ NVME_IOCTL_GET_ATTR_V0SZ
+
#endif /* _NVME_H */
diff --git a/include/uapi/linux/nvme_ioctl.h b/include/uapi/linux/nvme_ioctl.h
index 2f76cba67166..57b05d26f682 100644
--- a/include/uapi/linux/nvme_ioctl.h
+++ b/include/uapi/linux/nvme_ioctl.h
@@ -92,6 +92,28 @@ struct nvme_uring_cmd {
__u32 rsvd2;
};
+/*
+ * This struct is populated from the following nvme commands:
+ * [1] Identify Controller Data Structure
+ * [2] I/O Command Set Specific Identify Controller Data Structure for the
+ * NVME Command Set. Usually contained in struct nvme_id_ctrl_nvm
+ * [3] Controller capabilities on controller initialization
+ */
+struct nvme_get_attr {
+ __u32 argsz;
+ __u32 flags;
+
+ __u32 mpsmin;
+ __u8 vsl;
+ __u8 wzsl;
+ __u8 wusl;
+ __u8 dmrl;
+ __u64 dmsl;
+ __u32 dmrsl;
+ __u16 oncs;
+ __u8 mdts;
+};
+
#define nvme_admin_cmd nvme_passthru_cmd
#define NVME_IOCTL_ID _IO('N', 0x40)
@@ -104,6 +126,7 @@ struct nvme_uring_cmd {
#define NVME_IOCTL_ADMIN64_CMD _IOWR('N', 0x47, struct nvme_passthru_cmd64)
#define NVME_IOCTL_IO64_CMD _IOWR('N', 0x48, struct nvme_passthru_cmd64)
#define NVME_IOCTL_IO64_CMD_VEC _IOWR('N', 0x49, struct nvme_passthru_cmd64)
+#define NVME_IOCTL_GET_ATTR _IOWR('N', 0x50, struct nvme_get_attr)
/* io_uring async commands: */
#define NVME_URING_CMD_IO _IOWR('N', 0x80, struct nvme_uring_cmd)
--
2.30.2
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