From patchwork Mon Mar 2 03:32:34 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Douglas Gilbert X-Patchwork-Id: 11414701 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8ABC414B7 for ; Mon, 2 Mar 2020 03:33:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 60ACF24672 for ; Mon, 2 Mar 2020 03:33:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726997AbgCBDd2 (ORCPT ); Sun, 1 Mar 2020 22:33:28 -0500 Received: from smtp.infotech.no ([82.134.31.41]:60570 "EHLO smtp.infotech.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726755AbgCBDd1 (ORCPT ); Sun, 1 Mar 2020 22:33:27 -0500 Received: from localhost (localhost [127.0.0.1]) by smtp.infotech.no (Postfix) with ESMTP id B815E20424C; Mon, 2 Mar 2020 04:33:25 +0100 (CET) X-Virus-Scanned: by amavisd-new-2.6.6 (20110518) (Debian) at infotech.no Received: from smtp.infotech.no ([127.0.0.1]) by localhost (smtp.infotech.no [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 6DDPVvWbCjAF; Mon, 2 Mar 2020 04:33:23 +0100 (CET) Received: from xtwo70.bingwo.ca (host-23-251-188-50.dyn.295.ca [23.251.188.50]) by smtp.infotech.no (Postfix) with ESMTPA id AE34120414E; Mon, 2 Mar 2020 04:33:18 +0100 (CET) From: Douglas Gilbert To: linux-scsi@vger.kernel.org Cc: martin.petersen@oracle.com, jejb@linux.vnet.ibm.com, hare@suse.de Subject: [PATCH v8 23/38] sg: xarray for fds in device Date: Sun, 1 Mar 2020 22:32:34 -0500 Message-Id: <20200302033249.4515-24-dgilbert@interlog.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200302033249.4515-1-dgilbert@interlog.com> References: <20200302033249.4515-1-dgilbert@interlog.com> MIME-Version: 1.0 Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Add xarray in each sg_device object holding pointers to children. The children are sg_fd objects, each associated with an open file descriptor. The xarray replaces a doubly linked list and its access lock. Reviewed-by: Hannes Reinecke Signed-off-by: Douglas Gilbert --- drivers/scsi/sg.c | 157 +++++++++++++++++++--------------------------- 1 file changed, 65 insertions(+), 92 deletions(-) diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 0073272a069f..05c1688b763e 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -42,6 +42,7 @@ static char *sg_version_date = "20190606"; #include #include /* for sg_check_file_access() */ #include +#include #include "scsi.h" #include @@ -52,7 +53,6 @@ static char *sg_version_date = "20190606"; #include "scsi_logging.h" - #define SG_ALLOW_DIO_DEF 0 #define SG_MAX_DEVS 32768 @@ -174,13 +174,13 @@ struct sg_request { /* SG_MAX_QUEUE requests outstanding per file */ }; struct sg_fd { /* holds the state of a file descriptor */ - struct list_head sfd_entry; /* member sg_device::sfds list */ struct sg_device *parentdp; /* owning device */ wait_queue_head_t read_wait; /* queue read until command done */ spinlock_t rq_list_lock; /* protect access to list in req_arr */ struct mutex f_mutex; /* protect against changes in this fd */ int timeout; /* defaults to SG_DEFAULT_TIMEOUT */ int timeout_user; /* defaults to SG_DEFAULT_TIMEOUT_USER */ + u32 idx; /* my index within parent's sfp_arr */ atomic_t submitted; /* number inflight or awaiting read */ atomic_t waiting; /* number of requests awaiting read */ int sgat_elem_sz; /* initialized to scatter_elem_sz */ @@ -203,7 +203,6 @@ struct sg_device { /* holds the state of each scsi generic device */ wait_queue_head_t open_wait; /* queue open() when O_EXCL present */ struct mutex open_rel_lock; /* held when in open() or release() */ struct list_head sfds; - rwlock_t sfd_lock; /* protect access to sfd list */ int max_sgat_elems; /* adapter's max number of elements in sgat */ int max_sgat_sz; /* max number of bytes in sgat list */ u32 index; /* device index number */ @@ -211,6 +210,7 @@ struct sg_device { /* holds the state of each scsi generic device */ unsigned long fdev_bm[1]; /* see SG_FDEV_* defines above */ struct gendisk *disk; struct cdev * cdev; /* char_dev [sysfs: /sys/cdev/major/sg] */ + struct xarray sfp_arr; struct kref d_ref; }; @@ -248,12 +248,7 @@ static struct sg_request *sg_add_request(struct sg_fd *sfp); static void sg_deact_request(struct sg_fd *sfp, struct sg_request *srp); static struct sg_device *sg_get_dev(int dev); static void sg_device_destroy(struct kref *kref); -static void sg_calc_sgat_param(struct sg_device *sdp); static const char *sg_rq_st_str(enum sg_rq_state rq_st, bool long_str); -static void sg_rep_rq_state_fail(struct sg_fd *sfp, - enum sg_rq_state exp_old_st, - enum sg_rq_state want_st, - enum sg_rq_state act_old_st); #define SZ_SG_HEADER ((int)sizeof(struct sg_header)) /* v1 and v2 header */ #define SZ_SG_IO_HDR ((int)sizeof(struct sg_io_hdr)) /* v3 header */ @@ -262,7 +257,6 @@ static void sg_rep_rq_state_fail(struct sg_fd *sfp, #define SG_IS_DETACHING(sdp) test_bit(SG_FDEV_DETACHING, (sdp)->fdev_bm) #define SG_HAVE_EXCLUDE(sdp) test_bit(SG_FDEV_EXCLUDE, (sdp)->fdev_bm) #define SG_RS_ACTIVE(srp) (atomic_read(&(srp)->rq_st) != SG_RS_INACTIVE) -#define SG_RS_AWAIT_READ(srp) (atomic_read(&(srp)->rq_st) == SG_RS_AWAIT_RCV) /* * Kernel needs to be built with CONFIG_SCSI_LOGGING to see log messages. @@ -401,6 +395,7 @@ sg_open(struct inode *inode, struct file *filp) int min_dev = iminor(inode); int op_flags = filp->f_flags; int res; + __maybe_unused int o_count; struct sg_device *sdp; struct sg_fd *sfp; @@ -450,20 +445,18 @@ sg_open(struct inode *inode, struct file *filp) if (o_excl) set_bit(SG_FDEV_EXCLUDE, sdp->fdev_bm); - if (atomic_read(&sdp->open_cnt) < 1) /* no existing opens */ - sg_calc_sgat_param(sdp); + o_count = atomic_inc_return(&sdp->open_cnt); sfp = sg_add_sfp(sdp); /* increments sdp->d_ref */ if (IS_ERR(sfp)) { + atomic_dec(&sdp->open_cnt); res = PTR_ERR(sfp); goto out_undo; } filp->private_data = sfp; - atomic_inc(&sdp->open_cnt); mutex_unlock(&sdp->open_rel_lock); - SG_LOG(3, sfp, "%s: minor=%d, op_flags=0x%x; %s count prior=%d%s\n", - __func__, min_dev, op_flags, "device open", - atomic_read(&sdp->open_cnt), + SG_LOG(3, sfp, "%s: minor=%d, op_flags=0x%x; %s count after=%d%s\n", + __func__, min_dev, op_flags, "device open", o_count, ((op_flags & O_NONBLOCK) ? " O_NONBLOCK" : "")); res = 0; @@ -491,26 +484,30 @@ sg_open(struct inode *inode, struct file *filp) static int sg_release(struct inode *inode, struct file *filp) { + int o_count; struct sg_device *sdp; struct sg_fd *sfp; sfp = filp->private_data; - sdp = sfp->parentdp; - SG_LOG(3, sfp, "%s: device open count prior=%d\n", __func__, - atomic_read(&sdp->open_cnt)); - if (!sdp) + sdp = sfp ? sfp->parentdp : NULL; + if (unlikely(!sdp)) return -ENXIO; mutex_lock(&sdp->open_rel_lock); + o_count = atomic_read(&sdp->open_cnt); + SG_LOG(3, sfp, "%s: open count before=%d\n", __func__, o_count); scsi_autopm_put_device(sdp->device); kref_put(&sfp->f_ref, sg_remove_sfp); - atomic_dec(&sdp->open_cnt); + /* + * Possibly many open()s waiting on exlude clearing, start many; + * only open(O_EXCL)'s wait when open_cnt<2 and only start one. + */ /* possibly many open()s waiting on exlude clearing, start many; * only open(O_EXCL)s wait on 0==open_cnt so only start one */ if (test_and_clear_bit(SG_FDEV_EXCLUDE, sdp->fdev_bm)) wake_up_interruptible_all(&sdp->open_wait); - else if (atomic_read(&sdp->open_cnt) == 0) + else if (o_count < 2) wake_up_interruptible(&sdp->open_wait); mutex_unlock(&sdp->open_rel_lock); return 0; @@ -790,21 +787,6 @@ sg_common_write(struct sg_fd *sfp, struct sg_comm_wr_t *cwrp) return 0; } -static inline int -sg_rstate_chg(struct sg_request *srp, enum sg_rq_state old_st, - enum sg_rq_state new_st) -{ - enum sg_rq_state act_old_st = (enum sg_rq_state) - atomic_cmpxchg(&srp->rq_st, old_st, new_st); - - if (act_old_st == old_st) - return 0; /* implies new_st --> srp->rq_st */ - else if (IS_ENABLED(CONFIG_SCSI_LOGGING)) - sg_rep_rq_state_fail(srp->parentfp, old_st, new_st, - act_old_st); - return -EPROTOTYPE; -} - /* * This function is called by wait_event_interruptible in sg_read() and * sg_ctl_ioreceive(). wait_event_interruptible will return if this one @@ -865,32 +847,6 @@ sg_rec_state_v3(struct sg_fd *sfp, struct sg_request *srp) return 0; } -#if IS_ENABLED(CONFIG_SCSI_LOGGING) -static void -sg_rep_rq_state_fail(struct sg_fd *sfp, enum sg_rq_state exp_old_st, - enum sg_rq_state want_st, enum sg_rq_state act_old_st) -{ - const char *eors = "expected old rq_st: "; - const char *aors = "actual old rq_st: "; - - if (IS_ENABLED(CONFIG_SCSI_PROC_FS)) - SG_LOG(1, sfp, "%s: %s%s, %s%s, wanted rq_st: %s\n", __func__, - eors, sg_rq_st_str(exp_old_st, false), - aors, sg_rq_st_str(act_old_st, false), - sg_rq_st_str(want_st, false)); - else - pr_info("sg: %s: %s%d, %s%d, wanted rq_st: %d\n", __func__, - eors, (int)exp_old_st, aors, (int)act_old_st, - (int)want_st); -} -#else -static void -sg_rep_rq_state_fail(struct sg_fd *sfp, enum sg_rq_state exp_old_st, - enum sg_rq_state want_st, enum sg_rq_state act_old_st) -{ -} -#endif - static ssize_t sg_receive_v3(struct sg_fd *sfp, struct sg_request *srp, size_t count, void __user *p) @@ -1494,6 +1450,8 @@ sg_ioctl_common(struct file *filp, struct sg_device *sdp, struct sg_fd *sfp, if (result) return result; assign_bit(SG_FDEV_LOG_SENSE, sdp->fdev_bm, val); + if (val == 0) /* user can force recalculation */ + sg_calc_sgat_param(sdp); return 0; case BLKSECTGET: SG_LOG(3, sfp, "%s: BLKSECTGET\n", __func__); @@ -1921,11 +1879,9 @@ sg_add_device_helper(struct gendisk *disk, struct scsi_device *scsidp) sdp->disk = disk; sdp->device = scsidp; mutex_init(&sdp->open_rel_lock); - INIT_LIST_HEAD(&sdp->sfds); + xa_init_flags(&sdp->sfp_arr, XA_FLAGS_ALLOC | XA_FLAGS_LOCK_IRQ); init_waitqueue_head(&sdp->open_wait); clear_bit(SG_FDEV_DETACHING, sdp->fdev_bm); - rwlock_init(&sdp->sfd_lock); - sg_calc_sgat_param(sdp); sdp->index = k; kref_init(&sdp->d_ref); error = 0; @@ -1998,6 +1954,7 @@ sg_add_device(struct device *cl_dev, struct class_interface *cl_intf) } else pr_warn("%s: sg_sys Invalid\n", __func__); + sg_calc_sgat_param(sdp); sdev_printk(KERN_NOTICE, scsidp, "Attached scsi generic sg%d " "type %d\n", sdp->index, scsidp->type); @@ -2029,6 +1986,7 @@ sg_device_destroy(struct kref *kref) * any other cleanup. */ + xa_destroy(&sdp->sfp_arr); write_lock_irqsave(&sg_index_lock, flags); idr_remove(&sg_index_idr, sdp->index); write_unlock_irqrestore(&sg_index_lock, flags); @@ -2045,7 +2003,7 @@ sg_remove_device(struct device *cl_dev, struct class_interface *cl_intf) { struct scsi_device *scsidp = to_scsi_device(cl_dev->parent); struct sg_device *sdp = dev_get_drvdata(cl_dev); - unsigned long iflags; + unsigned long idx; struct sg_fd *sfp; if (!sdp) @@ -2057,13 +2015,13 @@ sg_remove_device(struct device *cl_dev, struct class_interface *cl_intf) SCSI_LOG_TIMEOUT(3, sdev_printk(KERN_INFO, sdp->device, "%s: 0x%pK\n", __func__, sdp)); - read_lock_irqsave(&sdp->sfd_lock, iflags); - list_for_each_entry(sfp, &sdp->sfds, sfd_entry) { + xa_for_each(&sdp->sfp_arr, idx, sfp) { + if (!sfp) + continue; wake_up_interruptible_all(&sfp->read_wait); kill_fasync(&sfp->async_qp, SIGPOLL, POLL_HUP); } wake_up_interruptible_all(&sdp->open_wait); - read_unlock_irqrestore(&sdp->sfd_lock, iflags); sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic"); device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, sdp->index)); @@ -2604,9 +2562,11 @@ sg_deact_request(struct sg_fd *sfp, struct sg_request *srp) static struct sg_fd * sg_add_sfp(struct sg_device *sdp) { - int rbuf_len; + int rbuf_len, res; + u32 idx; unsigned long iflags; struct sg_fd *sfp; + struct xa_limit xal; sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN); if (!sfp) @@ -2634,14 +2594,10 @@ sg_add_sfp(struct sg_device *sdp) atomic_set(&sfp->submitted, 0); atomic_set(&sfp->waiting, 0); - write_lock_irqsave(&sdp->sfd_lock, iflags); if (SG_IS_DETACHING(sdp)) { - write_unlock_irqrestore(&sdp->sfd_lock, iflags); kfree(sfp); return ERR_PTR(-ENODEV); } - list_add_tail(&sfp->sfd_entry, &sdp->sfds); - write_unlock_irqrestore(&sdp->sfd_lock, iflags); SG_LOG(3, sfp, "%s: sfp=0x%pK\n", __func__, sfp); if (unlikely(sg_big_buff != def_reserved_size)) sg_big_buff = def_reserved_size; @@ -2650,6 +2606,20 @@ sg_add_sfp(struct sg_device *sdp) if (rbuf_len > 0) sg_build_reserve(sfp, rbuf_len); + xa_lock_irqsave(&sdp->sfp_arr, iflags); + xal.min = 0; + xal.max = atomic_read(&sdp->open_cnt); + res = __xa_alloc(&sdp->sfp_arr, &idx, sfp, xal, GFP_KERNEL); + xa_unlock_irqrestore(&sdp->sfp_arr, iflags); + if (res < 0) { + pr_warn("%s: xa_alloc(sdp) bad, o_count=%d, errno=%d\n", + __func__, xal.max, -res); + if (rbuf_len > 0) + sg_remove_sgat(sfp, &sfp->reserve); + kfree(sfp); + return ERR_PTR(res); + } + sfp->idx = idx; kref_get(&sdp->d_ref); __module_get(THIS_MODULE); SG_LOG(3, sfp, "%s: success, sfp=0x%pK ++\n", __func__, sfp); @@ -2668,9 +2638,11 @@ sg_add_sfp(struct sg_device *sdp) static void sg_remove_sfp_usercontext(struct work_struct *work) { + __maybe_unused int o_count; unsigned long iflags; - struct sg_fd *sfp = container_of(work, struct sg_fd, ew_fd.work); struct sg_device *sdp; + struct sg_fd *sfp = container_of(work, struct sg_fd, ew_fd.work); + struct sg_fd *e_sfp; struct sg_request *srp; if (!sfp) { @@ -2695,7 +2667,15 @@ sg_remove_sfp_usercontext(struct work_struct *work) sg_remove_sgat(sfp, &sfp->reserve); } - SG_LOG(6, sfp, "%s: sfp=0x%pK\n", __func__, sfp); + xa_lock_irqsave(&sdp->sfp_arr, iflags); + e_sfp = __xa_erase(&sdp->sfp_arr, sfp->idx); + xa_unlock_irqrestore(&sdp->sfp_arr, iflags); + if (unlikely(sfp != e_sfp)) + SG_LOG(1, sfp, "%s: xa_erase() return unexpected\n", + __func__); + o_count = atomic_dec_return(&sdp->open_cnt); + SG_LOG(3, sfp, "%s: dev o_count after=%d: sfp=0x%pK --\n", __func__, + o_count, sfp); kfree(sfp); if (sdp) { @@ -2708,13 +2688,7 @@ sg_remove_sfp_usercontext(struct work_struct *work) static void sg_remove_sfp(struct kref *kref) { - unsigned long iflags; struct sg_fd *sfp = container_of(kref, struct sg_fd, f_ref); - struct sg_device *sdp = sfp->parentdp; - - write_lock_irqsave(&sdp->sfd_lock, iflags); - list_del(&sfp->sfd_entry); - write_unlock_irqrestore(&sdp->sfd_lock, iflags); INIT_WORK(&sfp->ew_fd.work, sg_remove_sfp_usercontext); schedule_work(&sfp->ew_fd.work); @@ -3029,6 +3003,7 @@ static void sg_proc_debug_helper(struct seq_file *s, struct sg_device *sdp) { int k, new_interface, blen, usg; + unsigned long idx; struct sg_request *srp; struct sg_fd *fp; const struct sg_io_hdr *hp; @@ -3036,15 +3011,15 @@ sg_proc_debug_helper(struct seq_file *s, struct sg_device *sdp) unsigned int ms; k = 0; - list_for_each_entry(fp, &sdp->sfds, sfd_entry) { + xa_for_each(&sdp->sfp_arr, idx, fp) { + if (!fp) + continue; k++; spin_lock(&fp->rq_list_lock); /* irqs already disabled */ - seq_printf(s, " FD(%d): timeout=%dms buflen=%d " - "(res)sgat=%d low_dma=%d\n", k, - jiffies_to_msecs(fp->timeout), - fp->reserve.buflen, - (int)fp->reserve.num_sgat, - (int) sdp->device->host->unchecked_isa_dma); + seq_printf(s, " FD(%d): timeout=%dms buflen=%d (res)sgat=%d low_dma=%d idx=%lu\n", + k, jiffies_to_msecs(fp->timeout), + fp->reserve.buflen, (int)fp->reserve.num_sgat, + (int)sdp->device->host->unchecked_isa_dma, idx); seq_printf(s, " cmd_q=%d f_packid=%d k_orphan=%d closed=0\n", (int) fp->cmd_q, (int) fp->force_packid, (int) fp->keep_orphan); @@ -3108,8 +3083,7 @@ sg_proc_seq_show_debug(struct seq_file *s, void *v) sdp = it ? sg_lookup_dev(it->index) : NULL; if (NULL == sdp) goto skip; - read_lock(&sdp->sfd_lock); - if (!list_empty(&sdp->sfds)) { + if (!xa_empty(&sdp->sfp_arr)) { seq_printf(s, " >>> device=%s ", sdp->disk->disk_name); if (SG_IS_DETACHING(sdp)) seq_puts(s, "detaching pending close "); @@ -3127,7 +3101,6 @@ sg_proc_seq_show_debug(struct seq_file *s, void *v) atomic_read(&sdp->open_cnt)); sg_proc_debug_helper(s, sdp); } - read_unlock(&sdp->sfd_lock); skip: read_unlock_irqrestore(&sg_index_lock, iflags); return 0;