On 03/20/2010 09:15 PM, Douglas Gilbert wrote: > In response to > http://bugzilla.kernel.org/show_bug.cgi?id=15565 > and the fact this capability has been present > in bsg for some time, add SG_FLAG_Q_AT_TAIL flag. It has > the same binary value as the bsg flag and the define name > is the same apart from the leading "B". The semantics are > the same, namely to override the default queue at head > action of the SCSI midlevel when a low level driver > blocks (i.e. when a LLD returns non-zero to a > queuecommand() ). Tested with scsi_debug. > > Changelog > - add SG_FLAG_Q_AT_TAIL flag to override default > queue at head semantics of the SCSI midlevel queue. > > Signed-off-by: Douglas Gilbert <dgilbert@xxxxxxxxxxxx> Review-by: Boaz Harrosh <bharrosh@xxxxxxxxxxx> > --- linux/include/scsi/sg.h 2008-10-10 17:04:54.000000000 -0400 > +++ linux/include/scsi/sg.h2633qat1 2010-03-20 14:28:31.000000000 -0400 > @@ -11,9 +11,9 @@ > Original driver (sg.h): > * Copyright (C) 1992 Lawrence Foard > Version 2 and 3 extensions to driver: > -* Copyright (C) 1998 - 2006 Douglas Gilbert > +* Copyright (C) 1998 - 2010 Douglas Gilbert > > - Version: 3.5.34 (20060920) > + Version: 3.5.35 (20100319) > This version is for 2.6 series kernels. > > For a full changelog see http://www.torque.net/sg > @@ -124,6 +124,7 @@ > #define SG_FLAG_UNUSED_LUN_INHIBIT 2 /* default is overwrite lun in SCSI */ > /* command block (when <= SCSI_2) */ > #define SG_FLAG_MMAP_IO 4 /* request memory mapped IO */ > +#define SG_FLAG_Q_AT_TAIL 0x10 /* default, without this flag, is Q_AT_HEAD */ I have chosen this value exactly so it can fit with SG as well. > #define SG_FLAG_NO_DXFER 0x10000 /* no transfer of kernel buffers to/from */ > /* user space (debug indirect IO) */ > > --- linux/drivers/scsi/sg.c 2009-12-03 11:11:18.000000000 -0500 > +++ linux/drivers/scsi/sg.c2633qat1 2010-03-19 19:42:10.000000000 -0400 > @@ -18,8 +18,8 @@ > * > */ > > -static int sg_version_num = 30534; /* 2 digits for each component */ > -#define SG_VERSION_STR "3.5.34" > +static int sg_version_num = 30535; /* 2 digits for each component */ > +#define SG_VERSION_STR "3.5.35" > > /* > * D. P. Gilbert (dgilbert@xxxxxxxxxxxx, dougg@xxxxxxxxxxxxx), notes: > @@ -61,7 +61,7 @@ > > #ifdef CONFIG_SCSI_PROC_FS > #include <linux/proc_fs.h> > -static char *sg_version_date = "20061027"; > +static char *sg_version_date = "20100319"; > > static int sg_proc_init(void); > static void sg_proc_cleanup(void); > @@ -710,8 +710,11 @@ I wish you would have used diff "-p" option that shows us the function this hunk is at. (git diff does that by default) > int k, data_dir; > Sg_device *sdp = sfp->parentdp; > sg_io_hdr_t *hp = &srp->header; > + int at_head = 1; > > srp->data.cmd_opcode = cmnd[0]; /* hold opcode of command */ > + if ('\0' != hp->interface_id) /* old interface misuses flags */ > + at_head = (SG_FLAG_Q_AT_TAIL & hp->flags) ? 0 : 1; > hp->status = 0; > hp->masked_status = 0; > hp->msg_status = 0; > @@ -753,7 +756,7 @@ > srp->rq->timeout = timeout; > kref_get(&sfp->f_ref); /* sg_rq_end_io() does kref_put(). */ > blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk, > - srp->rq, 1, sg_rq_end_io); > + srp->rq, at_head, sg_rq_end_io); Grate, this simple thing does wonders to performance. > return 0; > } > Thanks for doing this Boaz -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
