Fixed failure of sg_read to a nvme device:
1. Send sg_read command to a nvme device failed,
because the block size in user-mode is 4096 bytes,
not equal to the bolck size in kernel-mode, who is
512 bytes. According to the func nvme_trans_io of
scsi.c in the dir "drivers/nvme/host". The code
fragmentS as follows:
/* If block count and actual data buffer size dont match, error out */
if (xfer_bytes != (cdb_info.xfer_len << ns->lba_shift)) {
res = -EINVAL;
goto out;
}
2. And the SCSI-to-NVMe translations will be removed in
the patch "nvme: Remove SCSI translations" in the linux-nvme,
so using the nvme_read command is a good idea.
Signed-off-by: Yang Feng <philip.yang@xxxxxxxxxx>
---
libmultipath/prioritizers/path_latency.c | 78 +++++++++++++++++++++++++++-----
1 file changed, 66 insertions(+), 12 deletions(-)
diff --git a/libmultipath/prioritizers/path_latency.c b/libmultipath/prioritizers/path_latency.c
index 34b734b..8f633e0 100644
--- a/libmultipath/prioritizers/path_latency.c
+++ b/libmultipath/prioritizers/path_latency.c
@@ -23,14 +23,32 @@
#include <math.h>
#include <ctype.h>
#include <time.h>
-
#include "debug.h"
#include "prio.h"
#include "structs.h"
+#include <linux/types.h>
+#include <sys/ioctl.h>
#include "../checkers/libsg.h"
#define pp_pl_log(prio, fmt, args...) condlog(prio, "path_latency prio: " fmt, ##args)
+struct nvme_user_io {
+ __u8 opcode;
+ __u8 flags;
+ __u16 control;
+ __u16 nblocks;
+ __u16 rsvd;
+ __u64 metadata;
+ __u64 addr;
+ __u64 slba;
+ __u32 dsmgmt;
+ __u32 reftag;
+ __u16 apptag;
+ __u16 appmask;
+};
+
+#define NVME_IOCTL_SUBMIT_IO _IOW('N', 0x42, struct nvme_user_io)
+
#define MAX_IO_NUM 200
#define MIN_IO_NUM 2
@@ -51,19 +69,55 @@ static long long path_latency[MAX_IO_NUM];
static inline long long timeval_to_us(const struct timespec *tv)
{
- return ((long long) tv->tv_sec * USEC_PER_SEC) + (tv->tv_nsec / NSEC_PER_USEC);
+ return ((long long) tv->tv_sec * USEC_PER_SEC) + (tv->tv_nsec / NSEC_PER_USEC);
+}
+
+int nvme_io(int fd, __u8 opcode, __u64 slba, __u16 nblocks, __u16 control,
+ __u32 dsmgmt, __u32 reftag, __u16 apptag, __u16 appmask, void *data, void *metadata)
+{
+ struct nvme_user_io io = {
+ .opcode = opcode,
+ .flags = 0,
+ .control = control,
+ .nblocks = nblocks,
+ .rsvd = 0,
+ .metadata = (__u64)(uintptr_t) metadata,
+ .addr = (__u64)(uintptr_t) data,
+ .slba = slba,
+ .dsmgmt = dsmgmt,
+ .reftag = reftag,
+ .appmask = apptag,
+ .apptag = appmask,
+ };
+
+ return ioctl(fd, NVME_IOCTL_SUBMIT_IO, &io);
+}
+
+int nvme_read(int fd, __u64 slba, __u16 nblocks, __u16 control, __u32 dsmgmt,
+ __u32 reftag, __u16 apptag, __u16 appmask, void *data, void *metadata)
+{
+ return nvme_io(fd, 0x2, slba, nblocks, control, dsmgmt,
+ reftag, apptag, appmask, data, metadata);
}
-static int do_readsector0(int fd, unsigned int timeout)
+static int do_readsector0(struct path *pp, unsigned int timeout)
{
- unsigned char buf[4096];
- unsigned char sbuf[SENSE_BUFF_LEN];
- int ret;
+ unsigned char buf[4096];
+ unsigned char mbuf[512];
+ unsigned char sbuf[SENSE_BUFF_LEN];
- ret = sg_read(fd, &buf[0], 4096, &sbuf[0],
- SENSE_BUFF_LEN, timeout);
+ if (!strncmp(pp->dev, "nvme", 4))
+ {
+ if (nvme_read(pp->fd, 0, 1, 0, 0, 0, 0, 0, buf, mbuf) < 0)
+ return 0;
+ }
+ else
+ {
+ if (sg_read(pp->fd, &buf[0], 4096, &sbuf[0],SENSE_BUFF_LEN, timeout) == 2)
+ return 0;
+ }
- return ret;
+ return 1;
}
int check_args_valid(int io_num, int base_num)
@@ -218,9 +272,9 @@ int getprio (struct path *pp, char *args, unsigned int timeout)
(void)clock_gettime(CLOCK_MONOTONIC, &tv);
before = timeval_to_us(&tv);
- if (do_readsector0(pp->fd, timeout) == 2)
+ if (do_readsector0(pp, timeout) == 0)
{
- pp_pl_log(0, "%s: path down", pp->dev);
+ pp_pl_log(0, "%s: send read sector0 command fail", pp->dev);
return -1;
}
@@ -246,7 +300,7 @@ int getprio (struct path *pp, char *args, unsigned int timeout)
Warn the user if latency_interval is smaller than (2 * standard_deviation), or equal */
standard_deviation = calc_standard_deviation(path_latency, index, avglatency);
latency_interval = calc_latency_interval(avglatency, MAX_AVG_LATENCY, MIN_AVG_LATENCY, base_num);
- if ((latency_interval!= 0)
+ if ((latency_interval != 0)
&& (latency_interval <= (2 * standard_deviation)))
pp_pl_log(3, "%s: latency interval (%lld) according to average latency (%lld us) is smaller than "
"2 * standard deviation (%lld us), or equal, args base_num (%d) needs to be set bigger value",
--
2.6.4.windows.1
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