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264 lines
9.6 KiB
Diff
264 lines
9.6 KiB
Diff
From 8093bf02878aa659cfcf8cbfc272b2ad45eef24f Mon Sep 17 00:00:00 2001
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From: Douglas Gilbert <dgilbert@interlog.com>
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Date: Tue, 03 Jun 2014 13:18:18 -0400
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Subject: [PATCH] BACKPORT: sg: relax 16 byte cdb restriction
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- remove the 16 byte CDB (SCSI command) length limit from the sg driver
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by handling longer CDBs the same way as the bsg driver. Remove comment
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from sg.h public interface about the cmd_len field being limited to 16
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bytes.
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- remove some dead code caused by this change
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- cleanup comment block at the top of sg.h, fix urls
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Change-Id: Ie8150e5375b3316d5d5206f079c4a50f1c50b755
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Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
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Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
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Reviewed-by: Hannes Reinecke <hare@suse.de>
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Signed-off-by: Christoph Hellwig <hch@lst.de>
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---
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diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
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index 216d31f..56178bc 100644
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--- a/drivers/scsi/sg.c
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+++ b/drivers/scsi/sg.c
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@@ -7,9 +7,7 @@
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* Original driver (sg.c):
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* Copyright (C) 1992 Lawrence Foard
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* Version 2 and 3 extensions to driver:
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- * Copyright (C) 1998 - 2005 Douglas Gilbert
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- *
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- * Modified 19-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
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+ * Copyright (C) 1998 - 2014 Douglas Gilbert
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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@@ -18,11 +16,11 @@
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*
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*/
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-static int sg_version_num = 30534; /* 2 digits for each component */
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-#define SG_VERSION_STR "3.5.34"
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+static int sg_version_num = 30536; /* 2 digits for each component */
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+#define SG_VERSION_STR "3.5.36"
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/*
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- * D. P. Gilbert (dgilbert@interlog.com, dougg@triode.net.au), notes:
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+ * D. P. Gilbert (dgilbert@interlog.com), notes:
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* - scsi logging is available via SCSI_LOG_TIMEOUT macros. First
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* the kernel/module needs to be built with CONFIG_SCSI_LOGGING
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* (otherwise the macros compile to empty statements).
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@@ -63,7 +61,7 @@
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#ifdef CONFIG_SCSI_PROC_FS
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#include <linux/proc_fs.h>
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-static char *sg_version_date = "20061027";
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+static char *sg_version_date = "20140603";
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static int sg_proc_init(void);
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static void sg_proc_cleanup(void);
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@@ -72,6 +70,12 @@
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#define SG_ALLOW_DIO_DEF 0
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#define SG_MAX_DEVS 32768
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+
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+/* SG_MAX_CDB_SIZE should be 260 (spc4r37 section 3.1.30) however the type
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+ * of sg_io_hdr::cmd_len can only represent 255. All SCSI commands greater
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+ * than 16 bytes are "variable length" whose length is a multiple of 4
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+ */
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+#define SG_MAX_CDB_SIZE 252
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/*
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* Suppose you want to calculate the formula muldiv(x,m,d)=int(x * m / d)
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@@ -159,7 +163,7 @@
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char force_packid; /* 1 -> pack_id input to read(), 0 -> ignored */
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volatile char closed; /* 1 -> fd closed but request(s) outstanding */
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char cmd_q; /* 1 -> allow command queuing, 0 -> don't */
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- char next_cmd_len; /* 0 -> automatic (def), >0 -> use on next write() */
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+ unsigned char next_cmd_len; /* 0: automatic, >0: use on next write() */
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char keep_orphan; /* 0 -> drop orphan (def), 1 -> keep for read() */
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char mmap_called; /* 0 -> mmap() never called on this fd */
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struct kref f_ref;
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@@ -542,7 +546,7 @@
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Sg_request *srp;
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struct sg_header old_hdr;
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sg_io_hdr_t *hp;
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- unsigned char cmnd[MAX_COMMAND_SIZE];
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+ unsigned char cmnd[SG_MAX_CDB_SIZE];
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if (unlikely(segment_eq(get_fs(), KERNEL_DS)))
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return -EINVAL;
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@@ -577,12 +581,6 @@
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buf += SZ_SG_HEADER;
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__get_user(opcode, buf);
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if (sfp->next_cmd_len > 0) {
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- if (sfp->next_cmd_len > MAX_COMMAND_SIZE) {
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- SCSI_LOG_TIMEOUT(1, printk("sg_write: command length too long\n"));
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- sfp->next_cmd_len = 0;
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- sg_remove_request(sfp, srp);
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- return -EIO;
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- }
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cmd_size = sfp->next_cmd_len;
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sfp->next_cmd_len = 0; /* reset so only this write() effected */
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} else {
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@@ -654,7 +652,7 @@
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int k;
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Sg_request *srp;
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sg_io_hdr_t *hp;
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- unsigned char cmnd[MAX_COMMAND_SIZE];
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+ unsigned char cmnd[SG_MAX_CDB_SIZE];
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int timeout;
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unsigned long ul_timeout;
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@@ -1647,15 +1645,27 @@
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struct request_queue *q = sfp->parentdp->device->request_queue;
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struct rq_map_data *md, map_data;
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int rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? WRITE : READ;
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+ unsigned char *long_cmdp = NULL;
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SCSI_LOG_TIMEOUT(4, printk(KERN_INFO "sg_start_req: dxfer_len=%d\n",
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dxfer_len));
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+ if (hp->cmd_len > BLK_MAX_CDB) {
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+ long_cmdp = kzalloc(hp->cmd_len, GFP_KERNEL);
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+ if (!long_cmdp)
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+ return -ENOMEM;
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+ }
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+
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rq = blk_get_request(q, rw, GFP_ATOMIC);
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- if (!rq)
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+ if (!rq) {
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+ kfree(long_cmdp);
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return -ENOMEM;
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+ }
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blk_rq_set_block_pc(rq);
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+
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+ if (hp->cmd_len > BLK_MAX_CDB)
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+ rq->cmd = long_cmdp;
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memcpy(rq->cmd, cmd, hp->cmd_len);
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rq->cmd_len = hp->cmd_len;
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@@ -1740,6 +1750,8 @@
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if (srp->bio)
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ret = blk_rq_unmap_user(srp->bio);
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+ if (srp->rq->cmd != srp->rq->__cmd)
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+ kfree(srp->rq->cmd);
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blk_put_request(srp->rq);
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}
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diff --git a/include/scsi/sg.h b/include/scsi/sg.h
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index a9f3c6f..d8c0c43 100644
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--- a/include/scsi/sg.h
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+++ b/include/scsi/sg.h
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@@ -4,77 +4,34 @@
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#include <linux/compiler.h>
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/*
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- History:
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- Started: Aug 9 by Lawrence Foard (entropy@world.std.com), to allow user
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- process control of SCSI devices.
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- Development Sponsored by Killy Corp. NY NY
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-Original driver (sg.h):
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-* Copyright (C) 1992 Lawrence Foard
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-Version 2 and 3 extensions to driver:
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-* Copyright (C) 1998 - 2006 Douglas Gilbert
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-
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- Version: 3.5.34 (20060920)
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- This version is for 2.6 series kernels.
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-
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- For a full changelog see http://www.torque.net/sg
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-
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-Map of SG verions to the Linux kernels in which they appear:
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- ---------- ----------------------------------
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- original all kernels < 2.2.6
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- 2.1.40 2.2.20
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- 3.0.x optional version 3 sg driver for 2.2 series
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- 3.1.17++ 2.4.0++
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- 3.5.30++ 2.6.0++
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-
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-Major new features in SG 3.x driver (cf SG 2.x drivers)
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- - SG_IO ioctl() combines function if write() and read()
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- - new interface (sg_io_hdr_t) but still supports old interface
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- - scatter/gather in user space, direct IO, and mmap supported
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-
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- The normal action of this driver is to use the adapter (HBA) driver to DMA
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- data into kernel buffers and then use the CPU to copy the data into the
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- user space (vice versa for writes). That is called "indirect" IO due to
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- the double handling of data. There are two methods offered to remove the
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- redundant copy: 1) direct IO and 2) using the mmap() system call to map
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- the reserve buffer (this driver has one reserve buffer per fd) into the
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- user space. Both have their advantages.
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- In terms of absolute speed mmap() is faster. If speed is not a concern,
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- indirect IO should be fine. Read the documentation for more information.
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-
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- ** N.B. To use direct IO 'echo 1 > /proc/scsi/sg/allow_dio' or
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- 'echo 1 > /sys/module/sg/parameters/allow_dio' is needed.
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- That attribute is 0 by default. **
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-
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- Historical note: this SCSI pass-through driver has been known as "sg" for
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- a decade. In broader kernel discussions "sg" is used to refer to scatter
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- gather techniques. The context should clarify which "sg" is referred to.
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-
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- Documentation
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- =============
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- A web site for the SG device driver can be found at:
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- http://www.torque.net/sg [alternatively check the MAINTAINERS file]
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- The documentation for the sg version 3 driver can be found at:
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- http://www.torque.net/sg/p/sg_v3_ho.html
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- This is a rendering from DocBook source [change the extension to "sgml"
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- or "xml"]. There are renderings in "ps", "pdf", "rtf" and "txt" (soon).
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- The SG_IO ioctl is now found in other parts kernel (e.g. the block layer).
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- For more information see http://www.torque.net/sg/sg_io.html
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-
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- The older, version 2 documents discuss the original sg interface in detail:
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- http://www.torque.net/sg/p/scsi-generic.txt
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- http://www.torque.net/sg/p/scsi-generic_long.txt
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- Also available: <kernel_source>/Documentation/scsi/scsi-generic.txt
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-
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- Utility and test programs are available at the sg web site. They are
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- packaged as sg3_utils (for the lk 2.4 and 2.6 series) and sg_utils
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- (for the lk 2.2 series).
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-*/
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+ * History:
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+ * Started: Aug 9 by Lawrence Foard (entropy@world.std.com), to allow user
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+ * process control of SCSI devices.
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+ * Development Sponsored by Killy Corp. NY NY
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+ *
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+ * Original driver (sg.h):
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+ * Copyright (C) 1992 Lawrence Foard
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+ * Version 2 and 3 extensions to driver:
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+ * Copyright (C) 1998 - 2014 Douglas Gilbert
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+ *
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+ * Version: 3.5.36 (20140603)
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+ * This version is for 2.6 and 3 series kernels.
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+ *
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+ * Documentation
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+ * =============
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+ * A web site for the SG device driver can be found at:
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+ * http://sg.danny.cz/sg [alternatively check the MAINTAINERS file]
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+ * The documentation for the sg version 3 driver can be found at:
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+ * http://sg.danny.cz/sg/p/sg_v3_ho.html
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+ * Also see: <kernel_source>/Documentation/scsi/scsi-generic.txt
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+ *
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+ * For utility and test programs see: http://sg.danny.cz/sg/sg3_utils.html
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+ */
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#ifdef __KERNEL__
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extern int sg_big_buff; /* for sysctl */
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#endif
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-/* New interface introduced in the 3.x SG drivers follows */
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typedef struct sg_iovec /* same structure as used by readv() Linux system */
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{ /* call. It defines one scatter-gather element. */
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@@ -87,7 +44,7 @@
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{
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int interface_id; /* [i] 'S' for SCSI generic (required) */
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int dxfer_direction; /* [i] data transfer direction */
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- unsigned char cmd_len; /* [i] SCSI command length ( <= 16 bytes) */
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+ unsigned char cmd_len; /* [i] SCSI command length */
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unsigned char mx_sb_len; /* [i] max length to write to sbp */
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unsigned short iovec_count; /* [i] 0 implies no scatter gather */
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unsigned int dxfer_len; /* [i] byte count of data transfer */
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