99ff385fd0
reduce lock congestion and improve SMP scalability of the SCSI/ATA stack, preparing the ground for the coming next GEOM direct dispatch support. Replace big per-SIM locks with bunch of smaller ones: - per-LUN locks to protect device and peripheral drivers state; - per-target locks to protect list of LUNs on target; - per-bus locks to protect reference counting; - per-send queue locks to protect queue of CCBs to be sent; - per-done queue locks to protect queue of completed CCBs; - remaining per-SIM locks now protect only HBA driver internals. While holding LUN lock it is allowed (while not recommended for performance reasons) to take SIM lock. The opposite acquisition order is forbidden. All the other locks are leaf locks, that can be taken anywhere, but should not be cascaded. Many functions, such as: xpt_action(), xpt_done(), xpt_async(), xpt_create_path(), etc. are no longer require (but allow) SIM lock to be held. To keep compatibility and solve cases where SIM lock can't be dropped, all xpt_async() calls in addition to xpt_done() calls are queued to completion threads for async processing in clean environment without SIM lock held. Instead of single CAM SWI thread, used for commands completion processing before, use multiple (depending on number of CPUs) threads. Load balanced between them using "hash" of the device B:T:L address. HBA drivers that can drop SIM lock during completion processing and have sufficient number of completion threads to efficiently scale to multiple CPUs can use new function xpt_done_direct() to avoid extra context switch. Make ahci(4) driver to use this mechanism depending on hardware setup. Sponsored by: iXsystems, Inc. MFC after: 2 months
138 lines
5.1 KiB
C
138 lines
5.1 KiB
C
/*-
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* Data structures and definitions for dealing with the
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* Common Access Method Transport (xpt) layer.
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*
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* Copyright (c) 1997 Justin T. Gibbs.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions, and the following disclaimer,
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* without modification, immediately at the beginning of the file.
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* 2. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _CAM_CAM_XPT_H
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#define _CAM_CAM_XPT_H 1
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/* Forward Declarations */
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union ccb;
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struct cam_periph;
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struct cam_ed;
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struct cam_sim;
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/*
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* Definition of a CAM path. Paths are created from bus, target, and lun ids
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* via xpt_create_path and allow for reference to devices without recurring
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* lookups in the edt.
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*/
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struct cam_path;
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/* Path functions */
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#ifdef _KERNEL
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/*
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* Definition of an async handler callback block. These are used to add
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* SIMs and peripherals to the async callback lists.
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*/
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struct async_node {
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SLIST_ENTRY(async_node) links;
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u_int32_t event_enable; /* Async Event enables */
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u_int32_t event_lock; /* Take SIM lock for handlers. */
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void (*callback)(void *arg, u_int32_t code,
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struct cam_path *path, void *args);
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void *callback_arg;
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};
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SLIST_HEAD(async_list, async_node);
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SLIST_HEAD(periph_list, cam_periph);
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void xpt_action(union ccb *new_ccb);
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void xpt_action_default(union ccb *new_ccb);
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union ccb *xpt_alloc_ccb(void);
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union ccb *xpt_alloc_ccb_nowait(void);
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void xpt_free_ccb(union ccb *free_ccb);
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void xpt_setup_ccb(struct ccb_hdr *ccb_h,
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struct cam_path *path,
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u_int32_t priority);
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void xpt_merge_ccb(union ccb *master_ccb,
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union ccb *slave_ccb);
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cam_status xpt_create_path(struct cam_path **new_path_ptr,
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struct cam_periph *perph,
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path_id_t path_id,
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target_id_t target_id, lun_id_t lun_id);
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cam_status xpt_create_path_unlocked(struct cam_path **new_path_ptr,
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struct cam_periph *perph,
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path_id_t path_id,
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target_id_t target_id, lun_id_t lun_id);
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int xpt_getattr(char *buf, size_t len, const char *attr,
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struct cam_path *path);
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void xpt_free_path(struct cam_path *path);
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void xpt_path_counts(struct cam_path *path, uint32_t *bus_ref,
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uint32_t *periph_ref, uint32_t *target_ref,
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uint32_t *device_ref);
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int xpt_path_comp(struct cam_path *path1,
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struct cam_path *path2);
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int xpt_path_comp_dev(struct cam_path *path,
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struct cam_ed *dev);
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void xpt_print_path(struct cam_path *path);
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void xpt_print_device(struct cam_ed *device);
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void xpt_print(struct cam_path *path, const char *fmt, ...);
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int xpt_path_string(struct cam_path *path, char *str,
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size_t str_len);
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path_id_t xpt_path_path_id(struct cam_path *path);
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target_id_t xpt_path_target_id(struct cam_path *path);
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lun_id_t xpt_path_lun_id(struct cam_path *path);
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int xpt_path_legacy_ata_id(struct cam_path *path);
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struct cam_sim *xpt_path_sim(struct cam_path *path);
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struct cam_periph *xpt_path_periph(struct cam_path *path);
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void xpt_async(u_int32_t async_code, struct cam_path *path,
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void *async_arg);
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void xpt_rescan(union ccb *ccb);
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void xpt_hold_boot(void);
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void xpt_release_boot(void);
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void xpt_lock_buses(void);
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void xpt_unlock_buses(void);
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struct mtx * xpt_path_mtx(struct cam_path *path);
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#define xpt_path_lock(path) mtx_lock(xpt_path_mtx(path))
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#define xpt_path_unlock(path) mtx_unlock(xpt_path_mtx(path))
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#define xpt_path_assert(path, what) mtx_assert(xpt_path_mtx(path), (what))
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#define xpt_path_owned(path) mtx_owned(xpt_path_mtx(path))
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#define xpt_path_sleep(path, chan, priority, wmesg, timo) \
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msleep((chan), xpt_path_mtx(path), (priority), (wmesg), (timo))
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cam_status xpt_register_async(int event, ac_callback_t *cbfunc,
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void *cbarg, struct cam_path *path);
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cam_status xpt_compile_path(struct cam_path *new_path,
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struct cam_periph *perph,
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path_id_t path_id,
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target_id_t target_id,
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lun_id_t lun_id);
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cam_status xpt_clone_path(struct cam_path **new_path,
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struct cam_path *path);
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void xpt_copy_path(struct cam_path *new_path,
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struct cam_path *path);
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void xpt_release_path(struct cam_path *path);
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#endif /* _KERNEL */
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#endif /* _CAM_CAM_XPT_H */
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