2005-04-17 06:20:36 +08:00
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#ifndef _SCSI_SCSI_TCQ_H
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#define _SCSI_SCSI_TCQ_H
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#include <linux/blkdev.h>
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#include <scsi/scsi_cmnd.h>
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#include <scsi/scsi_device.h>
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2006-08-30 21:45:51 +08:00
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#include <scsi/scsi_host.h>
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2005-04-17 06:20:36 +08:00
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#define SCSI_NO_TAG (-1) /* identify no tag in use */
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[PATCH] BLOCK: Make it possible to disable the block layer [try #6]
Make it possible to disable the block layer. Not all embedded devices require
it, some can make do with just JFFS2, NFS, ramfs, etc - none of which require
the block layer to be present.
This patch does the following:
(*) Introduces CONFIG_BLOCK to disable the block layer, buffering and blockdev
support.
(*) Adds dependencies on CONFIG_BLOCK to any configuration item that controls
an item that uses the block layer. This includes:
(*) Block I/O tracing.
(*) Disk partition code.
(*) All filesystems that are block based, eg: Ext3, ReiserFS, ISOFS.
(*) The SCSI layer. As far as I can tell, even SCSI chardevs use the
block layer to do scheduling. Some drivers that use SCSI facilities -
such as USB storage - end up disabled indirectly from this.
(*) Various block-based device drivers, such as IDE and the old CDROM
drivers.
(*) MTD blockdev handling and FTL.
(*) JFFS - which uses set_bdev_super(), something it could avoid doing by
taking a leaf out of JFFS2's book.
(*) Makes most of the contents of linux/blkdev.h, linux/buffer_head.h and
linux/elevator.h contingent on CONFIG_BLOCK being set. sector_div() is,
however, still used in places, and so is still available.
(*) Also made contingent are the contents of linux/mpage.h, linux/genhd.h and
parts of linux/fs.h.
(*) Makes a number of files in fs/ contingent on CONFIG_BLOCK.
(*) Makes mm/bounce.c (bounce buffering) contingent on CONFIG_BLOCK.
(*) set_page_dirty() doesn't call __set_page_dirty_buffers() if CONFIG_BLOCK
is not enabled.
(*) fs/no-block.c is created to hold out-of-line stubs and things that are
required when CONFIG_BLOCK is not set:
(*) Default blockdev file operations (to give error ENODEV on opening).
(*) Makes some /proc changes:
(*) /proc/devices does not list any blockdevs.
(*) /proc/diskstats and /proc/partitions are contingent on CONFIG_BLOCK.
(*) Makes some compat ioctl handling contingent on CONFIG_BLOCK.
(*) If CONFIG_BLOCK is not defined, makes sys_quotactl() return -ENODEV if
given command other than Q_SYNC or if a special device is specified.
(*) In init/do_mounts.c, no reference is made to the blockdev routines if
CONFIG_BLOCK is not defined. This does not prohibit NFS roots or JFFS2.
(*) The bdflush, ioprio_set and ioprio_get syscalls can now be absent (return
error ENOSYS by way of cond_syscall if so).
(*) The seclvl_bd_claim() and seclvl_bd_release() security calls do nothing if
CONFIG_BLOCK is not set, since they can't then happen.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-10-01 02:45:40 +08:00
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#ifdef CONFIG_BLOCK
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2014-01-17 19:06:53 +08:00
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static inline struct scsi_cmnd *scsi_mq_find_tag(struct Scsi_Host *shost,
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2014-10-30 21:46:00 +08:00
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int unique_tag)
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2014-01-17 19:06:53 +08:00
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{
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2014-10-30 21:46:00 +08:00
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u16 hwq = blk_mq_unique_tag_to_hwq(unique_tag);
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struct request *req = NULL;
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2014-01-17 19:06:53 +08:00
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2014-10-30 21:46:00 +08:00
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if (hwq < shost->tag_set.nr_hw_queues)
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req = blk_mq_tag_to_rq(shost->tag_set.tags[hwq],
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blk_mq_unique_tag_to_tag(unique_tag));
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2014-01-17 19:06:53 +08:00
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return req ? (struct scsi_cmnd *)req->special : NULL;
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}
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2005-04-17 06:20:36 +08:00
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/**
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* scsi_find_tag - find a tagged command by device
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* @SDpnt: pointer to the ScSI device
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2014-10-30 21:46:00 +08:00
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* @tag: tag generated by blk_mq_unique_tag()
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2005-04-17 06:20:36 +08:00
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*
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* Notes:
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* Only works with tags allocated by the generic blk layer.
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**/
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static inline struct scsi_cmnd *scsi_find_tag(struct scsi_device *sdev, int tag)
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{
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struct request *req;
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if (tag != SCSI_NO_TAG) {
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2014-01-17 19:06:53 +08:00
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if (shost_use_blk_mq(sdev->host))
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2014-10-30 21:46:00 +08:00
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return scsi_mq_find_tag(sdev->host, tag);
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2014-01-17 19:06:53 +08:00
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2014-10-30 21:46:00 +08:00
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req = blk_queue_find_tag(sdev->request_queue, tag);
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2005-04-17 06:20:36 +08:00
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return req ? (struct scsi_cmnd *)req->special : NULL;
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}
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/* single command, look in space */
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return sdev->current_cmnd;
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}
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2014-01-17 19:06:53 +08:00
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2006-08-30 21:45:51 +08:00
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/**
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* scsi_init_shared_tag_map - create a shared tag map
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* @shost: the host to share the tag map among all devices
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* @depth: the total depth of the map
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*/
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2006-09-01 21:28:48 +08:00
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static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth)
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2006-08-30 21:45:51 +08:00
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{
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2014-01-17 19:06:53 +08:00
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/*
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* We always have a shared tag map around when using blk-mq.
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*/
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if (shost_use_blk_mq(shost))
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return 0;
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2008-10-28 02:20:59 +08:00
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/*
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* If the shared tag map isn't already initialized, do it now.
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* This saves callers from having to check ->bqt when setting up
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* devices on the shared host (for libata)
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*/
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if (!shost->bqt) {
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shost->bqt = blk_init_tags(depth);
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if (!shost->bqt)
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return -ENOMEM;
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}
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return 0;
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2006-08-30 21:45:51 +08:00
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}
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2006-10-04 14:27:25 +08:00
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/**
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* scsi_host_find_tag - find the tagged command by host
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* @shost: pointer to scsi_host
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2014-10-30 21:46:00 +08:00
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* @tag: tag generated by blk_mq_unique_tag()
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2006-10-04 14:27:25 +08:00
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*
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* Notes:
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* Only works with tags allocated by the generic blk layer.
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**/
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static inline struct scsi_cmnd *scsi_host_find_tag(struct Scsi_Host *shost,
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int tag)
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{
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struct request *req;
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if (tag != SCSI_NO_TAG) {
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2014-01-17 19:06:53 +08:00
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if (shost_use_blk_mq(shost))
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2014-10-30 21:46:00 +08:00
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return scsi_mq_find_tag(shost, tag);
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2006-10-04 14:27:25 +08:00
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req = blk_map_queue_find_tag(shost->bqt, tag);
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return req ? (struct scsi_cmnd *)req->special : NULL;
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}
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return NULL;
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}
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[PATCH] BLOCK: Make it possible to disable the block layer [try #6]
Make it possible to disable the block layer. Not all embedded devices require
it, some can make do with just JFFS2, NFS, ramfs, etc - none of which require
the block layer to be present.
This patch does the following:
(*) Introduces CONFIG_BLOCK to disable the block layer, buffering and blockdev
support.
(*) Adds dependencies on CONFIG_BLOCK to any configuration item that controls
an item that uses the block layer. This includes:
(*) Block I/O tracing.
(*) Disk partition code.
(*) All filesystems that are block based, eg: Ext3, ReiserFS, ISOFS.
(*) The SCSI layer. As far as I can tell, even SCSI chardevs use the
block layer to do scheduling. Some drivers that use SCSI facilities -
such as USB storage - end up disabled indirectly from this.
(*) Various block-based device drivers, such as IDE and the old CDROM
drivers.
(*) MTD blockdev handling and FTL.
(*) JFFS - which uses set_bdev_super(), something it could avoid doing by
taking a leaf out of JFFS2's book.
(*) Makes most of the contents of linux/blkdev.h, linux/buffer_head.h and
linux/elevator.h contingent on CONFIG_BLOCK being set. sector_div() is,
however, still used in places, and so is still available.
(*) Also made contingent are the contents of linux/mpage.h, linux/genhd.h and
parts of linux/fs.h.
(*) Makes a number of files in fs/ contingent on CONFIG_BLOCK.
(*) Makes mm/bounce.c (bounce buffering) contingent on CONFIG_BLOCK.
(*) set_page_dirty() doesn't call __set_page_dirty_buffers() if CONFIG_BLOCK
is not enabled.
(*) fs/no-block.c is created to hold out-of-line stubs and things that are
required when CONFIG_BLOCK is not set:
(*) Default blockdev file operations (to give error ENODEV on opening).
(*) Makes some /proc changes:
(*) /proc/devices does not list any blockdevs.
(*) /proc/diskstats and /proc/partitions are contingent on CONFIG_BLOCK.
(*) Makes some compat ioctl handling contingent on CONFIG_BLOCK.
(*) If CONFIG_BLOCK is not defined, makes sys_quotactl() return -ENODEV if
given command other than Q_SYNC or if a special device is specified.
(*) In init/do_mounts.c, no reference is made to the blockdev routines if
CONFIG_BLOCK is not defined. This does not prohibit NFS roots or JFFS2.
(*) The bdflush, ioprio_set and ioprio_get syscalls can now be absent (return
error ENOSYS by way of cond_syscall if so).
(*) The seclvl_bd_claim() and seclvl_bd_release() security calls do nothing if
CONFIG_BLOCK is not set, since they can't then happen.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-10-01 02:45:40 +08:00
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#endif /* CONFIG_BLOCK */
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2005-04-17 06:20:36 +08:00
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#endif /* _SCSI_SCSI_TCQ_H */
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