Replace sg_get_rq_mark() with sg_find_srp_by_id() and
sg_get_ready_srp(). Add sg_chk_mmap() to check flags and
reserve buffer available for mmap() based requests. Add
sg_copy_sense() and sg_rec_state_v3() which is just
refactoring. Add sg_calc_rq_dur() and sg_get_dur() in
preparation for optional nanosecond duration timing.
Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
Signed-off-by: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
---
drivers/scsi/sg.c | 345 ++++++++++++++++++++++++++++++----------------
1 file changed, 229 insertions(+), 116 deletions(-)
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 18881e551702..91bcb4d199b1 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -157,16 +157,19 @@ struct sg_fd;
struct sg_request { /* SG_MAX_QUEUE requests outstanding per file */
struct list_head entry; /* list entry */
- struct sg_fd *parentfp; /* NULL -> not in use */
struct sg_scatter_hold data; /* hold buffer, perhaps scatter list */
struct sg_io_hdr header; /* scsi command+info, see <scsi/sg.h> */
u8 sense_b[SCSI_SENSE_BUFFERSIZE];
+ u32 duration; /* cmd duration in milliseconds */
char res_used; /* 1 -> using reserve buffer, 0 -> not ... */
char orphan; /* 1 -> drop on sight, 0 -> normal */
char sg_io_owned; /* 1 -> packet belongs to SG_IO */
/* done protected by rq_list_lock */
char done; /* 0->before bh, 1->before read, 2->read */
atomic_t rq_st; /* request state, holds a enum sg_rq_state */
+ u64 start_ns; /* starting point of command duration calc */
+ unsigned long frq_bm[1]; /* see SG_FRQ_* defines above */
+ struct sg_fd *parentfp; /* pointer to owning fd, even when on fl */
struct request *rq; /* released in sg_rq_end_io(), bio kept */
struct bio *bio; /* kept until this req -->SG_RS_INACTIVE */
struct execute_work ew_orph; /* harvest orphan request */
@@ -232,7 +235,7 @@ static ssize_t sg_submit(struct sg_fd *sfp, struct file *filp,
const char __user *buf, size_t count, bool blocking,
bool read_only, bool sg_io_owned,
struct sg_request **o_srp);
-static int sg_common_write(struct sg_fd *sfp, struct sg_comm_wr_t *cwp);
+static int sg_common_write(struct sg_fd *sfp, struct sg_comm_wr_t *cwrp);
static int sg_read_append(struct sg_request *srp, void __user *outp,
int num_xfer);
static void sg_remove_sgat(struct sg_fd *sfp, struct sg_scatter_hold *schp);
@@ -242,8 +245,8 @@ static void sg_link_reserve(struct sg_fd *sfp, struct sg_request *srp,
static void sg_unlink_reserve(struct sg_fd *sfp, struct sg_request *srp);
static struct sg_fd *sg_add_sfp(struct sg_device *sdp);
static void sg_remove_sfp(struct kref *);
-static struct sg_request *sg_get_rq_mark(struct sg_fd *sfp, int pack_id,
- bool *busy);
+static struct sg_request *sg_find_srp_by_id(struct sg_fd *sfp, int pack_id,
+ bool *busy);
static struct sg_request *sg_setup_req(struct sg_fd *sfp);
static void sg_deact_request(struct sg_fd *sfp, struct sg_request *srp);
static struct sg_device *sg_get_dev(int dev);
@@ -446,7 +449,8 @@ sg_open(struct inode *inode, struct file *filp)
sfp = sg_add_sfp(sdp); /* increments sdp->d_ref */
if (IS_ERR(sfp)) {
res = PTR_ERR(sfp);
- goto out_undo; }
+ goto out_undo;
+ }
filp->private_data = sfp;
atomic_inc(&sdp->open_cnt);
@@ -509,7 +513,6 @@ sg_release(struct inode *inode, struct file *filp)
static ssize_t
sg_write(struct file *filp, const char __user *p, size_t count, loff_t *ppos)
{
- bool blocking = !(filp->f_flags & O_NONBLOCK);
int mxsize, cmd_size, input_size, res;
u8 opcode;
struct sg_device *sdp;
@@ -611,21 +614,19 @@ sg_write(struct file *filp, const char __user *p, size_t count, loff_t *ppos)
}
/*
* SG_DXFER_TO_FROM_DEV is functionally equivalent to SG_DXFER_FROM_DEV,
- * but is is possible that the app intended SG_DXFER_TO_DEV, because there
- * is a non-zero input_size, so emit a warning.
+ * but it is possible that the app intended SG_DXFER_TO_DEV, because
+ * there is a non-zero input_size, so emit a warning.
*/
if (h3p->dxfer_direction == SG_DXFER_TO_FROM_DEV) {
- printk_ratelimited(KERN_WARNING
- "sg_write: data in/out %d/%d bytes "
- "for SCSI command 0x%x-- guessing "
- "data in;\n program %s not setting "
- "count and/or reply_len properly\n",
- ohp->reply_len - (int)SZ_SG_HEADER,
- input_size, (unsigned int) cmnd[0],
- current->comm);
+ printk_ratelimited
+ (KERN_WARNING
+ "%s: data in/out %d/%d bytes for SCSI command 0x%x-- guessing data in;\n"
+ " program %s not setting count and/or reply_len properly\n",
+ __func__, ohp->reply_len - (int)SZ_SG_HEADER,
+ input_size, (unsigned int)cmnd[0], current->comm);
}
cwr.timeout = sfp->timeout;
- cwr.blocking = blocking;
+ cwr.blocking = !(filp->f_flags & O_NONBLOCK);
cwr.srp = srp;
cwr.cmnd = cmnd;
res = sg_common_write(sfp, &cwr);
@@ -654,6 +655,18 @@ sg_fetch_cmnd(struct file *filp, struct sg_fd *sfp, const u8 __user *u_cdbp,
return 0;
}
+static inline int
+sg_chk_mmap(struct sg_fd *sfp, int rq_flags, int len)
+{
+ if (len > sfp->reserve.buflen)
+ return -ENOMEM; /* MMAP_IO size must fit in reserve buffer */
+ if (rq_flags & SG_FLAG_DIRECT_IO)
+ return -EINVAL; /* either MMAP_IO or DIRECT_IO (not both) */
+ if (sfp->res_in_use)
+ return -EBUSY; /* reserve buffer already being used */
+ return 0;
+}
+
static ssize_t
sg_submit(struct sg_fd *sfp, struct file *filp, const char __user *buf,
size_t count, bool blocking, bool read_only, bool sg_io_owned,
@@ -687,17 +700,10 @@ sg_submit(struct sg_fd *sfp, struct file *filp, const char __user *buf,
return -ENOSYS;
}
if (hp->flags & SG_FLAG_MMAP_IO) {
- if (hp->dxfer_len > sfp->reserve.buflen) {
+ res = sg_chk_mmap(sfp, hp->flags, hp->dxfer_len);
+ if (res) {
sg_deact_request(sfp, srp);
- return -ENOMEM; /* MMAP_IO size must fit in reserve buffer */
- }
- if (hp->flags & SG_FLAG_DIRECT_IO) {
- sg_deact_request(sfp, srp);
- return -EINVAL; /* either MMAP_IO or DIRECT_IO (not both) */
- }
- if (sfp->res_in_use) {
- sg_deact_request(sfp, srp);
- return -EBUSY; /* reserve buffer already being used */
+ return res;
}
}
ul_timeout = msecs_to_jiffies(srp->header.timeout);
@@ -719,6 +725,12 @@ sg_submit(struct sg_fd *sfp, struct file *filp, const char __user *buf,
return count;
}
+/*
+ * All writes and submits converge on this function to launch the SCSI
+ * command/request (via blk_execute_rq_nowait). Returns a pointer to a
+ * sg_request object holding the request just issued or a negated errno
+ * value twisted by ERR_PTR.
+ */
static int
sg_common_write(struct sg_fd *sfp, struct sg_comm_wr_t *cwrp)
{
@@ -778,58 +790,69 @@ sg_common_write(struct sg_fd *sfp, struct sg_comm_wr_t *cwrp)
return 0;
}
-static int
-get_sg_io_pack_id(int *pack_id, void __user *buf, size_t count)
-{
- struct sg_header __user *old_hdr = buf;
- int reply_len;
-
- if (count >= SZ_SG_HEADER) {
- /* negative reply_len means v3 format, otherwise v1/v2 */
- if (get_user(reply_len, &old_hdr->reply_len))
- return -EFAULT;
-
- if (reply_len >= 0)
- return get_user(*pack_id, &old_hdr->pack_id);
+/*
+ * This function is called by wait_event_interruptible in sg_read() and
+ * sg_ctl_ioreceive(). wait_event_interruptible will return if this one
+ * returns true (or an event like a signal (e.g. control-C) occurs).
+ */
- if (in_compat_syscall() &&
- count >= sizeof(struct compat_sg_io_hdr)) {
- struct compat_sg_io_hdr __user *hp = buf;
+static inline bool
+sg_get_ready_srp(struct sg_fd *sfp, struct sg_request **srpp, int pack_id,
+ bool *busy)
+{
+ struct sg_request *srp = sg_find_srp_by_id(sfp, pack_id, busy);
- return get_user(*pack_id, &hp->pack_id);
- }
+ *srpp = srp;
+ return !!srp;
+}
- if (count >= sizeof(struct sg_io_hdr)) {
- struct sg_io_hdr __user *hp = buf;
+/*
+ * Returns number of bytes copied to user space provided sense buffer or
+ * negated errno value.
+ */
+static int
+sg_copy_sense(struct sg_request *srp)
+{
+ int sb_len_ret = 0;
+ struct sg_io_hdr *hp = &srp->header;
- return get_user(*pack_id, &hp->pack_id);
- }
+ /* If need be, copy the sense buffer to the user space */
+ if ((CHECK_CONDITION & hp->masked_status) ||
+ (srp->sense_b[0] & 0x70) == 0x70) {
+ int sb_len = SCSI_SENSE_BUFFERSIZE;
+ void __user *up = hp->sbp;
+
+ sb_len = min_t(int, hp->mx_sb_len, sb_len);
+ /* Additional sense length field */
+ sb_len_ret = 8 + (int)srp->sense_b[7];
+ sb_len_ret = min_t(int, sb_len_ret, sb_len);
+ if (copy_to_user(up, srp->sense_b, sb_len_ret))
+ return -EFAULT;
+ hp->sb_len_wr = sb_len_ret;
}
-
- /* no valid header was passed, so ignore the pack_id */
- *pack_id = -1;
- return 0;
+ return sb_len_ret;
}
static int
-srp_done(struct sg_fd *sfp, struct sg_request *srp)
+sg_rec_state_v3(struct sg_fd *sfp, struct sg_request *srp)
{
- unsigned long flags;
- int ret;
+ int sb_len_wr;
- spin_lock_irqsave(&sfp->rq_list_lock, flags);
- ret = srp->done;
- spin_unlock_irqrestore(&sfp->rq_list_lock, flags);
- return ret;
+ sb_len_wr = sg_copy_sense(srp);
+ if (sb_len_wr < 0)
+ return sb_len_wr;
+ if (unlikely(SG_IS_DETACHING(sfp->parentdp)))
+ return -ENODEV;
+ return 0;
}
+
static ssize_t
-sg_receive_v3(struct sg_fd *sfp, char __user *buf, size_t count,
- struct sg_request *srp)
+sg_receive_v3(struct sg_fd *sfp, struct sg_request *srp, size_t count,
+ void __user *buf)
{
- struct sg_io_hdr *hp = &srp->header;
int err = 0;
- int len;
+ struct sg_io_hdr *hp = &srp->header;
if (in_compat_syscall()) {
if (count < sizeof(struct compat_sg_io_hdr)) {
@@ -840,22 +863,9 @@ sg_receive_v3(struct sg_fd *sfp, char __user *buf, size_t count,
err = -EINVAL;
goto err_out;
}
- hp->sb_len_wr = 0;
- if ((hp->mx_sb_len > 0) && hp->sbp) {
- if ((CHECK_CONDITION & hp->masked_status) ||
- (srp->sense_b[0] & 0x70) == 0x70) {
- int sb_len = SCSI_SENSE_BUFFERSIZE;
- sb_len = (hp->mx_sb_len > sb_len) ? sb_len : hp->mx_sb_len;
- len = 8 + (int) srp->sense_b[7]; /* Additional sense length field */
- len = (len > sb_len) ? sb_len : len;
- if (copy_to_user(hp->sbp, srp->sense_b, len)) {
- err = -EFAULT;
- goto err_out;
- }
- hp->driver_status = DRIVER_SENSE;
- hp->sb_len_wr = len;
- }
- }
+ err = sg_rec_state_v3(sfp, srp);
+ if (err < 0)
+ goto err_out;
if (hp->masked_status || hp->host_status || hp->driver_status)
hp->info |= SG_INFO_CHECK;
err = put_sg_io_hdr(hp, buf);
@@ -940,6 +950,39 @@ sg_read_v1v2(void __user *buf, int count, struct sg_fd *sfp,
return res;
}
+static int
+get_sg_io_pack_id(int *pack_id, void __user *buf, size_t count)
+{
+ struct sg_header __user *old_hdr = buf;
+ int reply_len;
+
+ if (count >= SZ_SG_HEADER) {
+ /* negative reply_len means v3 format, otherwise v1/v2 */
+ if (get_user(reply_len, &old_hdr->reply_len))
+ return -EFAULT;
+
+ if (reply_len >= 0)
+ return get_user(*pack_id, &old_hdr->pack_id);
+
+ if (in_compat_syscall() &&
+ count >= sizeof(struct compat_sg_io_hdr)) {
+ struct compat_sg_io_hdr __user *hp = buf;
+
+ return get_user(*pack_id, &hp->pack_id);
+ }
+
+ if (count >= sizeof(struct sg_io_hdr)) {
+ struct sg_io_hdr __user *hp = buf;
+
+ return get_user(*pack_id, &hp->pack_id);
+ }
+ }
+
+ /* no valid header was passed, so ignore the pack_id */
+ *pack_id = -1;
+ return 0;
+}
+
static ssize_t
sg_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
{
@@ -968,12 +1011,12 @@ sg_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
if (ret)
return ret;
- srp = sg_get_rq_mark(sfp, req_pack_id, &busy);
+ srp = sg_find_srp_by_id(sfp, req_pack_id, &busy);
if (!srp) { /* now wait on packet to arrive */
if (non_block)
return -EAGAIN;
ret = wait_event_interruptible(sfp->read_wait,
- ((srp = sg_get_rq_mark(sfp, req_pack_id, &busy)) ||
+ ((srp = sg_find_srp_by_id(sfp, req_pack_id, &busy)) ||
(!busy && SG_IS_DETACHING(sdp))));
if (!srp)
/* signal or detaching */
@@ -982,7 +1025,7 @@ sg_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
if (srp->header.interface_id == '\0')
ret = sg_read_v1v2(buf, (int)count, sfp, srp);
else
- ret = sg_receive_v3(sfp, buf, count, srp);
+ ret = sg_receive_v3(sfp, srp, count, buf);
if (ret < 0)
SG_LOG(1, sfp, "%s: negated errno: %d\n", __func__, ret);
return ret < 0 ? ret : (int)count;
@@ -1031,6 +1074,51 @@ sg_calc_sgat_param(struct sg_device *sdp)
sdp->max_sgat_sz = sz;
}
+static u32
+sg_calc_rq_dur(const struct sg_request *srp)
+{
+ ktime_t ts0 = ns_to_ktime(srp->start_ns);
+ ktime_t now_ts;
+ s64 diff;
+
+ if (ts0 == 0)
+ return 0;
+ if (unlikely(ts0 == S64_MAX)) /* _prior_ to issuing req */
+ return 999999999; /* eye catching */
+ now_ts = ktime_get_boottime();
+ if (unlikely(ts0 > now_ts))
+ return 999999998;
+ /* unlikely req duration will exceed 2**32 milliseconds */
+ diff = ktime_ms_delta(now_ts, ts0);
+ return (diff > (s64)U32_MAX) ? 3999999999U : (u32)diff;
+}
+
+/* Return of U32_MAX means srp is inactive */
+static u32
+sg_get_dur(struct sg_request *srp, const enum sg_rq_state *sr_stp,
+ bool *is_durp)
+{
+ bool is_dur = false;
+ u32 res = U32_MAX;
+
+ switch (sr_stp ? *sr_stp : atomic_read(&srp->rq_st)) {
+ case SG_RS_INFLIGHT:
+ case SG_RS_BUSY:
+ res = sg_calc_rq_dur(srp);
+ break;
+ case SG_RS_AWAIT_RCV:
+ case SG_RS_INACTIVE:
+ res = srp->duration;
+ is_dur = true; /* completion has occurred, timing finished */
+ break;
+ default:
+ break;
+ }
+ if (is_durp)
+ *is_durp = is_dur;
+ return res;
+}
+
static void
sg_fill_request_table(struct sg_fd *sfp, struct sg_req_info *rinfo)
{
@@ -1047,6 +1135,7 @@ sg_fill_request_table(struct sg_fd *sfp, struct sg_req_info *rinfo)
srp->header.masked_status &
srp->header.host_status &
srp->header.driver_status;
+ rinfo[val].duration = sg_get_dur(srp, NULL, NULL); /* dummy */
if (srp->done)
rinfo[val].duration =
srp->header.duration;
@@ -1064,13 +1153,25 @@ sg_fill_request_table(struct sg_fd *sfp, struct sg_req_info *rinfo)
}
}
+static int
+srp_done(struct sg_fd *sfp, struct sg_request *srp)
+{
+ unsigned long flags;
+ int ret;
+
+ spin_lock_irqsave(&sfp->rq_list_lock, flags);
+ ret = srp->done;
+ spin_unlock_irqrestore(&sfp->rq_list_lock, flags);
+ return ret;
+}
+
/*
* Handles ioctl(SG_IO) for blocking (sync) usage of v3 or v4 interface.
* Returns 0 on success else a negated errno.
*/
static int
sg_ctl_sg_io(struct file *filp, struct sg_device *sdp, struct sg_fd *sfp,
- void __user *p)
+ void __user *buf)
{
bool read_only = O_RDWR != (filp->f_flags & O_ACCMODE);
int res;
@@ -1079,7 +1180,7 @@ sg_ctl_sg_io(struct file *filp, struct sg_device *sdp, struct sg_fd *sfp,
res = sg_allow_if_err_recovery(sdp, false);
if (res)
return res;
- res = sg_submit(sfp, filp, p, SZ_SG_IO_HDR, true, read_only,
+ res = sg_submit(sfp, filp, buf, SZ_SG_IO_HDR, true, read_only,
true, &srp);
if (res < 0)
return res;
@@ -1089,7 +1190,7 @@ sg_ctl_sg_io(struct file *filp, struct sg_device *sdp, struct sg_fd *sfp,
if (srp->done) {
srp->done = 2;
spin_unlock_irq(&sfp->rq_list_lock);
- res = sg_receive_v3(sfp, p, SZ_SG_IO_HDR, srp);
+ res = sg_receive_v3(sfp, srp, SZ_SG_IO_HDR, buf);
return (res < 0) ? res : 0;
}
srp->orphan = 1;
@@ -1317,7 +1418,9 @@ sg_ioctl_common(struct file *filp, struct sg_device *sdp, struct sg_fd *sfp,
return result;
if (val > SG_MAX_CDB_SIZE)
return -ENOMEM;
- sfp->next_cmd_len = (val > 0) ? val : 0;
+ mutex_lock(&sfp->f_mutex);
+ sfp->next_cmd_len = max_t(int, val, 0);
+ mutex_unlock(&sfp->f_mutex);
return 0;
case SG_GET_ACCESS_COUNT:
SG_LOG(3, sfp, "%s: SG_GET_ACCESS_COUNT\n", __func__);
@@ -2233,6 +2336,45 @@ sg_read_append(struct sg_request *srp, void __user *outp, int num_xfer)
return res;
}
+/*
+ * If there are multiple requests outstanding, the speed of this function is
+ * important. SG_PACK_ID_WILDCARD is -1 and that case is typically the fast
+ * path. This function is only used in the non-blocking cases. Returns pointer
+ * to (first) matching sg_request or NULL. If found, sg_request state is moved
+ * from SG_RS_AWAIT_RCV to SG_RS_BUSY.
+ * The 'busy' pointer is only set to true when no requests are found in the
+ * SG_RS_AWAIT_RCV state and SG_IS_DETACHING() is true and there is at least
+ * one request in SG_RS_INFLIGHT state; in all other cases *busy is set false.
+ */
+static struct sg_request *
+sg_find_srp_by_id(struct sg_fd *sfp, int pack_id, bool *busy)
+{
+ struct sg_request *resp;
+ unsigned long iflags;
+
+ *busy = false;
+ spin_lock_irqsave(&sfp->rq_list_lock, iflags);
+ list_for_each_entry(resp, &sfp->rq_list, entry) {
+ /* look for requests that are not SG_IO owned */
+ if ((!resp->sg_io_owned) &&
+ ((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
+ switch (resp->done) {
+ case 0: /* request active */
+ *busy = true;
+ break;
+ case 1: /* request done; response ready to return */
+ resp->done = 2; /* guard against other readers */
+ spin_unlock_irqrestore(&sfp->rq_list_lock, iflags);
+ return resp;
+ case 2: /* response already being returned */
+ break;
+ }
+ }
+ }
+ spin_unlock_irqrestore(&sfp->rq_list_lock, iflags);
+ return NULL;
+}
+
static void
sg_link_reserve(struct sg_fd *sfp, struct sg_request *srp, int size)
{
@@ -2279,35 +2421,6 @@ sg_unlink_reserve(struct sg_fd *sfp, struct sg_request *srp)
sfp->res_in_use = 0;
}
-static struct sg_request *
-sg_get_rq_mark(struct sg_fd *sfp, int pack_id, bool *busy)
-{
- struct sg_request *resp;
- unsigned long iflags;
-
- *busy = false;
- spin_lock_irqsave(&sfp->rq_list_lock, iflags);
- list_for_each_entry(resp, &sfp->rq_list, entry) {
- /* look for requests that are not SG_IO owned */
- if ((!resp->sg_io_owned) &&
- ((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
- switch (resp->done) {
- case 0: /* request active */
- *busy = true;
- break;
- case 1: /* request done; response ready to return */
- resp->done = 2; /* guard against other readers */
- spin_unlock_irqrestore(&sfp->rq_list_lock, iflags);
- return resp;
- case 2: /* response already being returned */
- break;
- }
- }
- }
- spin_unlock_irqrestore(&sfp->rq_list_lock, iflags);
- return NULL;
-}
-
static void
sg_build_reserve(struct sg_fd *sfp, int req_size)
{
--
2.37.3
