From patchwork Mon Mar 2 03:32:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Douglas Gilbert X-Patchwork-Id: 11414711 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 88B17930 for ; Mon, 2 Mar 2020 03:33:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 71D22246B6 for ; Mon, 2 Mar 2020 03:33:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727032AbgCBDdf (ORCPT ); Sun, 1 Mar 2020 22:33:35 -0500 Received: from smtp.infotech.no ([82.134.31.41]:60665 "EHLO smtp.infotech.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727018AbgCBDde (ORCPT ); Sun, 1 Mar 2020 22:33:34 -0500 Received: from localhost (localhost [127.0.0.1]) by smtp.infotech.no (Postfix) with ESMTP id F2ADF204248; Mon, 2 Mar 2020 04:33:32 +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 etYM7B+PwH99; Mon, 2 Mar 2020 04:33:30 +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 4F857204255; Mon, 2 Mar 2020 04:33:24 +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 28/38] sg: rework debug info Date: Sun, 1 Mar 2020 22:32:39 -0500 Message-Id: <20200302033249.4515-29-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 Since the version 2 driver, the state of the driver can be found with 'cat /proc/scsi/sg/debug'. As the driver becomes more threaded and IO faster (e.g. scsi_debug with a command timer of 5 microseconds), the existing state dump can become misleading as the state can change during the "snapshot". The new approach in this patch is to allocate a buffer of SG_PROC_DEBUG_SZ bytes and use scnprintf() to populate it. Only when the whole state is captured (or the buffer fills) is the output to the caller's terminal performed. The previous approach was line based: assemble a line of information and then output it. Locks are taken as required for short periods and should not interfere with a disk IO intensive program. Operations such as closing a sg file descriptor or removing a sg device may be held up for a short while (microseconds). Signed-off-by: Douglas Gilbert --- drivers/scsi/sg.c | 256 ++++++++++++++++++++++++++++++++-------------- 1 file changed, 177 insertions(+), 79 deletions(-) diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 882b5b8877bc..017897a1a2a4 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -2392,7 +2392,7 @@ sg_rq_end_io(struct request *rq, blk_status_t status) if (unlikely((srp->rq_result & SG_ML_RESULT_MSK) && slen > 0)) sg_check_sense(sdp, srp, slen); if (slen > 0) { - if (scsi_rp->sense) { + if (scsi_rp->sense && !srp->sense_bp) { srp->sense_bp = mempool_alloc(sg_sense_pool, GFP_ATOMIC); if (srp->sense_bp) { @@ -2405,6 +2405,9 @@ sg_rq_end_io(struct request *rq, blk_status_t status) pr_warn("%s: sense but can't alloc buffer\n", __func__); } + } else if (srp->sense_bp) { + slen = 0; + pr_warn("%s: non-NULL srp->sense_bp ? ?\n", __func__); } else { slen = 0; pr_warn("%s: sense_len>0 but sense==NULL\n", __func__); @@ -3931,116 +3934,211 @@ sg_proc_seq_show_devstrs(struct seq_file *s, void *v) return 0; } -/* must be called while holding sg_index_lock */ -static void -sg_proc_debug_helper(struct seq_file *s, struct sg_device *sdp) +/* Writes debug info for one sg_request in obp buffer */ +static int +sg_proc_debug_sreq(struct sg_request *srp, int to, char *obp, int len) { - int k; - unsigned long idx, idx2; + bool is_v3v4, v4, is_dur; + int n = 0; + u32 dur; + enum sg_rq_state rq_st; + const char *cp; + + if (len < 1) + return 0; + v4 = test_bit(SG_FRQ_IS_V4I, srp->frq_bm); + is_v3v4 = v4 ? true : (srp->s_hdr3.interface_id != '\0'); + if (srp->parentfp->rsv_srp == srp) + cp = (is_v3v4 && (srp->rq_flags & SG_FLAG_MMAP_IO)) ? + " mmap>> " : " rsv>> "; + else + cp = (srp->rq_info & SG_INFO_DIRECT_IO_MASK) ? + " dio>> " : " "; + rq_st = atomic_read(&srp->rq_st); + dur = sg_get_dur(srp, &rq_st, &is_dur); + n += scnprintf(obp + n, len - n, "%s%s: dlen=%d/%d id=%d", cp, + sg_rq_st_str(rq_st, false), srp->sgat_h.dlen, + srp->sgat_h.buflen, (int)srp->pack_id); + if (is_dur) /* cmd/req has completed, waiting for ... */ + n += scnprintf(obp + n, len - n, " dur=%ums", dur); + else if (dur < U32_MAX) /* in-flight or busy (so ongoing) */ + n += scnprintf(obp + n, len - n, " t_o/elap=%us/%ums", + to / 1000, dur); + n += scnprintf(obp + n, len - n, " sgat=%d op=0x%02x\n", + srp->sgat_h.num_sgat, srp->cmd_opcode); + return n; +} + +/* Writes debug info for one sg fd (including its sg requests) in obp buffer */ +static int +sg_proc_debug_fd(struct sg_fd *fp, char *obp, int len, unsigned long idx) +{ + int n = 0; + int to, k; + unsigned long iflags; struct sg_request *srp; - struct sg_fd *fp; - const char * cp; - unsigned int ms; + /* sgat=-1 means unavailable */ + to = (fp->timeout >= 0) ? jiffies_to_msecs(fp->timeout) : -999; + if (to < 0) + n += scnprintf(obp + n, len - n, "BAD timeout=%d", + fp->timeout); + else if (to % 1000) + n += scnprintf(obp + n, len - n, "timeout=%dms rs", to); + else + n += scnprintf(obp + n, len - n, "timeout=%ds rs", to / 1000); + n += scnprintf(obp + n, len - n, "v_buflen=%d idx=%lu\n cmd_q=%d ", + fp->rsv_srp->sgat_h.buflen, idx, + (int)test_bit(SG_FFD_CMD_Q, fp->ffd_bm)); + n += scnprintf(obp + n, len - n, + "f_packid=%d k_orphan=%d ffd_bm=0x%lx\n", + (int)test_bit(SG_FFD_FORCE_PACKID, fp->ffd_bm), + (int)test_bit(SG_FFD_KEEP_ORPHAN, fp->ffd_bm), + fp->ffd_bm[0]); + n += scnprintf(obp + n, len - n, " mmap_called=%d\n", + test_bit(SG_FFD_MMAP_CALLED, fp->ffd_bm)); + n += scnprintf(obp + n, len - n, + " submitted=%d waiting=%d open thr_id=%d\n", + atomic_read(&fp->submitted), + atomic_read(&fp->waiting), fp->tid); + k = 0; + xa_lock_irqsave(&fp->srp_arr, iflags); + xa_for_each(&fp->srp_arr, idx, srp) { + if (!srp) + continue; + if (xa_get_mark(&fp->srp_arr, idx, SG_XA_RQ_INACTIVE)) + continue; + n += sg_proc_debug_sreq(srp, fp->timeout, obp + n, len - n); + ++k; + if ((k % 8) == 0) { /* don't hold up isr_s too long */ + xa_unlock_irqrestore(&fp->srp_arr, iflags); + cpu_relax(); + xa_lock_irqsave(&fp->srp_arr, iflags); + } + } + if (k == 0) + n += scnprintf(obp + n, len - n, " No requests active\n"); k = 0; + xa_for_each_marked(&fp->srp_arr, idx, srp, SG_XA_RQ_INACTIVE) { + if (!srp) + continue; + if (k == 0) + n += scnprintf(obp + n, len - n, " Inactives:\n"); + n += sg_proc_debug_sreq(srp, fp->timeout, obp + n, len - n); + ++k; + if ((k % 8) == 0) { /* don't hold up isr_s too long */ + xa_unlock_irqrestore(&fp->srp_arr, iflags); + cpu_relax(); + xa_lock_irqsave(&fp->srp_arr, iflags); + } + } + xa_unlock_irqrestore(&fp->srp_arr, iflags); + return n; +} + +/* Writes debug info for one sg device (including its sg fds) in obp buffer */ +static int +sg_proc_debug_sdev(struct sg_device *sdp, char *obp, int len, int *fd_counterp) +{ + int n = 0; + int my_count = 0; + unsigned long idx; + struct scsi_device *ssdp = sdp->device; + struct sg_fd *fp; + char *disk_name; + int *countp; + + countp = fd_counterp ? fd_counterp : &my_count; + disk_name = (sdp->disk ? sdp->disk->disk_name : "?_?"); + n += scnprintf(obp + n, len - n, " >>> device=%s ", disk_name); + n += scnprintf(obp + n, len - n, "%d:%d:%d:%llu ", ssdp->host->host_no, + ssdp->channel, ssdp->id, ssdp->lun); + n += scnprintf(obp + n, len - n, + " max_sgat_sz,elems=2^%d,%d excl=%d open_cnt=%d\n", + ilog2(sdp->max_sgat_sz), sdp->max_sgat_elems, + SG_HAVE_EXCLUDE(sdp), atomic_read(&sdp->open_cnt)); xa_for_each(&sdp->sfp_arr, idx, fp) { if (!fp) continue; - k++; - 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->rsv_srp->sgat_h.buflen, - (int)fp->rsv_srp->sgat_h.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)test_bit(SG_FFD_CMD_Q, fp->ffd_bm), - (int)test_bit(SG_FFD_FORCE_PACKID, fp->ffd_bm), - (int)test_bit(SG_FFD_KEEP_ORPHAN, fp->ffd_bm)); - seq_printf(s, " submitted=%d waiting=%d\n", - atomic_read(&fp->submitted), - atomic_read(&fp->waiting)); - xa_for_each(&fp->srp_arr, idx2, srp) { - const struct sg_slice_hdr3 *sh3p = &srp->s_hdr3; - bool is_v3 = (sh3p->interface_id != '\0'); - enum sg_rq_state rq_st = atomic_read(&srp->rq_st); - - if (!srp) - continue; - if (srp->parentfp->rsv_srp == srp) { - if (is_v3 && (SG_FLAG_MMAP_IO & sh3p->flags)) - cp = " mmap>> "; - else - cp = " rb>> "; - } else { - if (SG_INFO_DIRECT_IO_MASK & srp->rq_info) - cp = " dio>> "; - else - cp = " "; - } - seq_puts(s, cp); - seq_puts(s, sg_rq_st_str(rq_st, false)); - seq_printf(s, ": id=%d len/blen=%d/%d", - srp->pack_id, srp->sgat_h.dlen, - srp->sgat_h.buflen); - if (rq_st == SG_RS_AWAIT_RCV || - rq_st == SG_RS_RCV_DONE) { - seq_printf(s, " dur=%d", srp->duration); - goto fin_line; - } - ms = jiffies_to_msecs(jiffies); - seq_printf(s, " t_o/elap=%d/%d", - (is_v3 ? sh3p->timeout : - jiffies_to_msecs(fp->timeout)), - (ms > srp->duration ? ms - srp->duration : - 0)); -fin_line: - seq_printf(s, "ms sgat=%d op=0x%02x\n", - srp->sgat_h.num_sgat, (int)srp->cmd_opcode); - } - if (xa_empty(&fp->srp_arr)) - seq_puts(s, " No requests active\n"); + ++*countp; + n += scnprintf(obp + n, len - n, " FD(%d): ", *countp); + n += sg_proc_debug_fd(fp, obp + n, len - n, idx); } + return n; } +/* Called via dbg_seq_ops once for each sg device */ static int sg_proc_seq_show_debug(struct seq_file *s, void *v) { + bool found = false; + bool trunc = false; + const int bp_len = SG_PROC_DEBUG_SZ; + int n = 0; + int k = 0; + unsigned long iflags; struct sg_proc_deviter *it = (struct sg_proc_deviter *)v; struct sg_device *sdp; - unsigned long iflags; + int *fdi_p; + char *bp; + char *disk_name; + char b1[128]; + b1[0] = '\0'; if (it && (0 == it->index)) seq_printf(s, "max_active_device=%d def_reserved_size=%d\n", - (int)it->max, sg_big_buff); - + (int)it->max, def_reserved_size); + fdi_p = it ? &it->fd_index : &k; + bp = kzalloc(bp_len, __GFP_NOWARN | GFP_KERNEL); + if (!bp) { + seq_printf(s, "%s: Unable to allocate %d on heap, finish\n", + __func__, bp_len); + return -1; + } read_lock_irqsave(&sg_index_lock, iflags); sdp = it ? sg_lookup_dev(it->index) : NULL; if (NULL == sdp) goto skip; if (!xa_empty(&sdp->sfp_arr)) { - seq_printf(s, " >>> device=%s ", sdp->disk->disk_name); + found = true; + disk_name = (sdp->disk ? sdp->disk->disk_name : "?_?"); if (SG_IS_DETACHING(sdp)) - seq_puts(s, "detaching pending close "); + snprintf(b1, sizeof(b1), " >>> device=%s %s\n", + disk_name, "detaching pending close\n"); else if (sdp->device) { - struct scsi_device *scsidp = sdp->device; - - seq_printf(s, "%d:%d:%d:%llu em=%d", - scsidp->host->host_no, - scsidp->channel, scsidp->id, - scsidp->lun, - scsidp->host->hostt->emulated); + n = sg_proc_debug_sdev(sdp, bp, bp_len, fdi_p); + if (n >= bp_len - 1) { + trunc = true; + if (bp[bp_len - 2] != '\n') + bp[bp_len - 2] = '\n'; + } + } else { + snprintf(b1, sizeof(b1), " >>> device=%s %s\n", + disk_name, "sdp->device==NULL, skip"); } - seq_printf(s, " max_sgat_sz=%d excl=%d open_cnt=%d\n", - sdp->max_sgat_sz, SG_HAVE_EXCLUDE(sdp), - atomic_read(&sdp->open_cnt)); - sg_proc_debug_helper(s, sdp); } skip: read_unlock_irqrestore(&sg_index_lock, iflags); + if (found) { + if (n > 0) { + seq_puts(s, bp); + if (seq_has_overflowed(s)) + goto s_ovfl; + if (trunc) + seq_printf(s, " >> Output truncated %s\n", + "due to buffer size"); + } else if (b1[0]) { + seq_puts(s, b1); + if (seq_has_overflowed(s)) + goto s_ovfl; + } + } +s_ovfl: + kfree(bp); return 0; } -#endif /* CONFIG_SCSI_PROC_FS (~300 lines back) */ +#endif /* CONFIG_SCSI_PROC_FS (~400 lines back) */ module_init(init_sg); module_exit(exit_sg);