Introduce the new sg_rq_state enumerations for tracking the
lifetime of a sg_request. SG_RQ_DATA_THRESHOLD is a
default value that if the data length of a request exceeds
then, after that request is completed, the data buffer will
be freed up as the sg_request object is placed on the free
list. SG_TOT_FD_THRESHOLD is a default, per file descriptor
value that the sum of outstanding command data lengths is not
allowed to exceed.
Signed-off-by: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
---
The '#if 0's are temporary and removed in a later patch.
They allow the following large and complex patch (5 of 8)
to be a bit shorter and still compile.
drivers/scsi/sg.c | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index 94e13a1d21a5..a76395f16fb1 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -75,6 +75,24 @@ static int sg_proc_init(void);
*/
#define SG_MAX_CDB_SIZE 252
+/* Following enum contains the states of sg_request::rq_state */
+enum sg_rq_state {
+ SG_RQ_INACTIVE = 0, /* request not in use (e.g. on fl) */
+ SG_RQ_INFLIGHT, /* SCSI request issued, no response yet */
+ SG_RQ_AWAIT_READ, /* response received, awaiting read */
+ SG_RQ_DONE_READ, /* read is ongoing or done */
+ SG_RQ_BUSY, /* example: reserve request changing size */
+};
+
+/* free up requests larger than this dlen size after use */
+#define SG_RQ_DATA_THRESHOLD (128 * 1024)
+
+/* If sum_of(dlen) of a fd exceeds this, write() will yield E2BIG */
+#define SG_TOT_FD_THRESHOLD (16 * 1024 * 1024)
+
+#define SG_TIME_UNIT_MS 0 /* milliseconds */
+#define SG_TIME_UNIT_NS 1 /* nanoseconds */
+#define SG_DEF_TIME_UNIT SG_TIME_UNIT_MS
#define SG_DEFAULT_TIMEOUT mult_frac(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ)
int sg_big_buff = SG_DEF_RESERVED_SIZE;
@@ -950,6 +968,7 @@ sg_fill_request_table(struct sg_fd *sfp, struct sg_req_info *rinfo)
}
}
+#if 0 /* temporary to shorten big patch */
static long
sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
{
@@ -1227,6 +1246,7 @@ sg_compat_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
return -ENOIOCTLCMD;
}
#endif
+#endif /* temporary to shorten big patch */
static __poll_t
sg_poll(struct file *filp, poll_table * wait)
@@ -1496,10 +1516,12 @@ static const struct file_operations sg_fops = {
.read = sg_read,
.write = sg_write,
.poll = sg_poll,
+#if 0 /* temporary to shorten big patch */
.unlocked_ioctl = sg_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = sg_compat_ioctl,
#endif
+#endif /* temporary to shorten big patch */
.open = sg_open,
.mmap = sg_mmap,
.release = sg_release,
@@ -2422,12 +2444,16 @@ static const struct seq_operations devstrs_seq_ops = {
.show = sg_proc_seq_show_devstrs,
};
+#if 0 /* temporary to shorten big patch */
static int sg_proc_seq_show_debug(struct seq_file *s, void *v);
+#endif /* temporary to shorten big patch */
static const struct seq_operations debug_seq_ops = {
.start = dev_seq_start,
.next = dev_seq_next,
.stop = dev_seq_stop,
+#if 0 /* temporary to shorten big patch */
.show = sg_proc_seq_show_debug,
+#endif /* temporary to shorten big patch */
};
static int
@@ -2601,6 +2627,8 @@ sg_proc_seq_show_devstrs(struct seq_file *s, void *v)
return 0;
}
+#if 0 /* temporary to shorten big patch */
+
/* must be called while holding sg_index_lock */
static void
sg_proc_debug_helper(struct seq_file *s, struct sg_device *sdp)
@@ -2704,6 +2732,7 @@ sg_proc_seq_show_debug(struct seq_file *s, void *v)
read_unlock_irqrestore(&sg_index_lock, iflags);
return 0;
}
+#endif /* temporary to shorten big patch */
#endif /* CONFIG_SCSI_PROC_FS */
--
2.17.1
